Foods That Fight Cancer
By
Patricia Hausman
Book Cover (Front) (Back)
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A Note To The Reader
1 - Good News At Last
2 - The Case For Prevention
3 - Vitamin A
4 - Vitamin C
5 - Fibre
6 - Cancer Inhibitors In Food
7 - Minerals
8 - Dietary Fat
9 - Alcohol
10 - Food Additives
11 - Naturally Occurring Toxins
12 - Cooking Methods
13 - Will Preventing Heart Disease Cause Higher Cancer Rates?
14 - A Quick Reference Guide
15 - Cookware For Cancer Prevention
Suggested Reading List (Removed)
Index (Removed)
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Genera: Health (Anti-Cancer)
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Copyright: 1987
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-Salmun
This book is based on mounting scientific research linking certain foods to reduced risk of cancer. On the basis of research now available, the author, along with other health professionals, believes that following the recommendations in this book should reduce the risk of developing certain forms of cancer. Of course, there can be no assurance given that following these recommendations will prevent cancer in any person.
Since some people cannot tolerate particular diets, the author urges the reader to consult a physician before making a major change in diet. Moreover, a physician should be consulted if the change in diet has adverse effects. Any person who for medical reasons has been prescribed a particular diet should especially consult with a physician before changing diets. Of course, anyone who has been diagnosed as suffering from cancer or any other condition should follow the treatment prescribed by a physician.
The recommendations in this book are intended as preventive measures only, not as curative treatment for persons suffering from cancer or other illnesses and conditions.
The science of nutrition has come of age. We now know that good nutrition safeguards our health in ways that we never dreamed were possible.
A few years ago, I would not have told you that good nutrition could help to protect you from cancer. Fellow nutritionists would have been sceptical of my faith in the foods that fight cancer. But today I can tell you that simple changes in your diet may very well reduce your chances of developing some forms of cancer.
A Major Change In Outlook
Most nutrition experts will agree that their ideas on diet and health have changed dramatically in the past ten years. I know that mine have. At that time I, along with many others revered animal foods with their high levels of protein, vitamins and minerals.
Although there was nothing particularly wrong with fruit and vegetables animal foods were considered richer in nutrients.
My main concern for action in nutrition in the mid-seventies was in food additives, sugar and refined grains. At that time, if I heard the words 'nutrition' and 'cancer' in the same sentence, I would have thought of food additives. But as research findings became known it became much clearer that fat and salt consumption could have an enormous impact on health. These probably constituted a much bigger problem than either sugar or food additives. There was overwhelming evidence that saturated fats and cholesterol helped to cause heart disease and that excessive salt intake contributes to high blood pressure. And high blood pressure greatly increased the chances of developing heart disease.
My concern about the effects of fat and salt consumption led me in 1978 to criticize the Recommended Dietary Allowances (RDA) formulated in the United States. I believed that the RDA approach to nutrition rewarded foods rich in protein, vitamins and minerals without any consideration of the amount of fat or salt that they contained. With these recommendations, foods that appear to be best for our health, because they are rich in protein and other nutrients, are actually high in fat and salt and can cause serious health problems.
A Bright Future
We know today that there are new areas of action on nutrition and diet that are just as important as eating less fat and salt.
Perhaps the most important development is that there are many substances in food that can actually give one protection against cancer. Instead of focusing only on the negative side of diet and disease we can now emphasize the positive aspects of good nutrition in the fight against cancer. There are many good research studies that show that some foods have anti-cancer potential.
For many years it seemed as though we were fighting a frustrating and losing battle against cancer. The hope that there would be a breakthrough (in the same way as penicillin emerged to combat infections) never seemed to be realized. But now experts believe that most common cancers are potentially preventable, and that the causes of the most common forms of cancer are generally determined by 'habit, diet, and custom rather than by genetic differences'. In the United States a report prepared for the Office of Technology Assessment (OTA) by two eminent British cancer experts, Sir Richard Doll and Richard Peto, ventured that changes in diet might reduce cancer rates in the country by 35 per cent. The World Health Organization believes that up to a third of all cancers can be prevented.
Diet May Help Prevent Ten Forms Of Cancer
There are many different kinds of cancer. I believe that good nutrition can help to prevent many, though not all, of them. In this book, we'll be talking about the things that you can do to protect yourself from those cancers that are sensitive to diet. The three major kinds are cancers of the colon - common in both men and women - lung cancer which has high rates of mortality in men, and breast cancer in women. Diet may also help prevent cancers of the mouth and throat, oesophagus, stomach, prostate, ovary, and rectum.
Help For Smokers And Gourmets
Most of us are creatures of habit and find it difficult, if not impossible, to do what is best for our health. We may appreciate the health hazards of our habits, but we sometimes feel unable to stop indulging in them. Thousands of people have tried to give up smoking, but have not succeeded. They are probably very tired of hearing only the 'stop smoking' message.
Of course it is best never to smoke or, failing that, to stop smoking if one has developed the habit. But research now shows that smokers who have diets rich in vitamin A are less likely to develop lung cancer than smokers who do not. It appears that a diet high in vitamin A helps those who cannot part with their cigarettes. This does not mean that eating lots of fruit and vegetables makes smoking acceptable. But there is good evidence that these can help to protect smokers to some degree.
Research has shown that a high fibre diet can balance out a diet rich in fat. Many people find high-fat foods too good to pass up.
They may not know that a high-fibre diet can counteract the ill effects of fat to some degree. It will not do away with all risks of developing colon cancer but it may help to reduce them, and counteract some of the damage.
Another cancer risk is from the chemicals used to cure meat. Cooked bacon, for example, often contains nitrosamines: these tiny amounts of nitrosamines can cause cancer in a number of animals.
However, research now shows that vitamin C can help to prevent nitrosamines from forming in the body. In some instances vitamin C has completely blocked the reaction that produces nitrosamines; in other cases it reduces the amount that forms.
New findings on the relationship between nutrition and cancer show that there are ways in which good nutrition can counteract our weaknesses. We must remember that nutrition cannot eliminate all risks. But it can reduce their impact.
There is a bonus - the same diet that can reduce the risk of cancer will also give you added protection from other common health problems. Heart disease, diabetes, diverticulosis - even obesity - are among the conditions that can benefit from the same diet that you will learn about in this book.
A Diet Tailor-made For You
How can a book give advice on preventing cancer when each of us has different genes and lifestyles and is exposed to different risks? When some smoke cigarettes, while others will avoid even a room with smokers in it?
I have tried to cope with what might be called our individuality.
Each chapter begins with a prominent section listing conditions that call for special attention to the food element discussed in that chapter. This should help you to identify the changes in diet that can best protect you. For example:
Even so, this book is not intended as a substitute for your doctor.
If you have a condition that puts you at an extra risk of cancer, discuss your diet with your doctor. There is a good chance that you can take steps to reduce that extra risk.
It Is Not Too Late
Many people seem to feel that there is no point in trying to change one's habits when one has been eating in a particular manner all one's life. They seem to believe that the damage is irreversible.
This is a pity because there is good scientific evidence to show that even changes made late in life can influence the course of some forms of cancer as well as of heart disease.
My research revealed, amazingly, that men who had changed to cholesterol-lowering diets during their forties, fifties and even sixties experienced some benefits to their heart health. When I looked at nutrition and colon cancer I found that even late-life changes affect the course of the disease. Studies in the United States have shown that when immigrants from other countries where colon cancer is relatively infrequent come to the United States, they develop the same high rates of colon cancer as American men.
This has been found repeatedly in surveys of immigrants from Japan, Poland and Norway. In all three cases newcomers from these countries soon showed a colon cancer rate that closely resembled the rate found in the United States rather than that which prevailed in their own home countries.
Scientists have a good idea of what happens. When they moved to the United States the Japanese men ate more fat. Had they continued to eat the traditional, low-fat Japanese diet they probably would have kept their risk of colon cancer very low.
Though we may never be able to account for every extra case of colon cancer among these adult immigrants, we can draw some conclusions from this research. These indicate that the chance of developing colon cancer can be influenced late in life.
Cancer scientists today believe that cancer has several stages. Initially a cell in the body suffers some damage. Whether it grows into cancer depends on a series of other stages.
One of the later stages is called promotion. During this phase factors such as nutrition can act to keep the cancer growing. They can also fight the cancer, or slow - or stop - its growth.
The experience of Japanese, Polish, and Norwegian migrants indicates that changes that occur during the promotional period - one of the last stages in the development of colon cancer - can influence whether the disease develops or not.
We can hope that future research will show whether nutrition can affect cancer, once it is diagnosed. For maximum benefit, of course, cancer-preventing food habits should be developed early in life. We have every reason to believe that the earlier such measures are adopted, the better the outcome will be.
Childhood Can Be Most Important
Being sensible about one's diet is not just for adults; it is very important for children as well. There are, however, certain adjustments that should be made. A diet low in fat, which is most appropriate for adults, is not recommended for children under one year old. Infants grow rapidly during their first year of life, and therefore a diet low in fat may not provide enough calories for their needs. But children should learn healthy eating habits from early on. Habits are not easy to break. If we learned to eat sensibly early in life, doing so as adults would be much easier.
Another reason to emphasize cancer-preventing food habits in childhood is that some cancers seem to be influenced most strongly by childhood and/or adolescence. For women, their lifestyle during the first twenty or thirty years becomes particularly important. For example, women who bear children early in life have less risk than those who have their first child later in life of developing breast cancer.
There is reason to believe that some other forms of cancer are particularly influenced by habits in early life. Cancers of the stomach and prostate gland also seem most sensitive to these.
So all things considered both young and old can benefit from eating habits that reduce the risk of cancer.
Good Health And Good Food
This subject does not have to mean boring food - nutritionists do love to eat well. I have spent thousands of hours in the kitchen experimenting with recipes and to develop my own ways of making low-fat, low-salt, highly nutritious food taste good. I'll be sharing some hints with you and also telling you about kitchenware that actually helps good nutrition taste very good.
A Great deal of money and effort has been invested in cancer treatment. Modern medical techniques have made significant advances in this field. This has led to success in cancer treatment.
Statistics from 15 industrialised countries have shown that in the 25 years from 1950 deaths from stomach cancer have fallen dramatically; generally dropping by 37 per cent in Japan to 64 per cent in Switzerland. They were down by 49 per cent in England and Wales.
Prevention Is Now A Priority
Despite the successes, prevention is better than cure. We do not have a guaranteed cure for every case of cancer. We do have good treatment for some, but not all, forms of the disease. But who wouldn't prefer preventing the disease to facing the uncertain outcome of our current treatment, even if the chances for recovery are good?
Exactly how many cases of cancer might be prevented no one can say but scientists have estimated, for example, that anywhere between thirty to sixty per cent of Americans who eventually develop cancer might be spared the disease by good nutrition.
The emphasis in cancer research is now changing. Forty years ago every scientist and doctor was inspired by the success of penicillin, a powerful weapon against life-threatening diseases. No wonder that they set out to find a drug that would also defeat cancer. But scientific research has now started a revolution amongst scientists themselves. There is an accumulation of evidence that indicates that most forms of cancer can be prevented. The very people who spent a lifetime looking for a cancer cure are now urging us to do more to prevent the disease ever occurring.
The Evidence For Prevention
What changed their minds? It was not sporadic, but consistent, evidence from many studies:
The meaning of these findings is clear. If some countries can manage to have low rates of breast cancer, it is obvious that the disease does not have to be common.
If the rich can avoid some forms of cancer, so can the poor. The wealthy can benefit, too, by adopting the habits that protect poor people from breast and colon cancers. And if migrating from one country can cut the chances of developing various forms of cancer, it is clear that cancer is not written onto our genes. Cancer, therefore, can be avoided.
The Food Habits That Help
About half a dozen dietary habits and practices are strongly linked to reduced rates of cancer.
Diet May Prevent The Most Common Cancers
As you can see, nutrition plays a promising role in preventing the most common forms of cancer. In men, these are cancers of the lung, prostate gland, colon and rectum, and bladder, and in women, breast cancer, followed by that of the colon and rectum, uterus, and lung.
There is evidence that good nutrition may help to prevent some other forms of cancer. I will discuss this in later chapters, but it is best to concentrate only on those dietary habits that show a strong connection with reduced rates of cancer.
There are cancers, of course, that have not been linked to diet. Those of the brain, eye, and thyroid gland show no relationship to eating habits, nor do leukaemia and Hodgkin's disease.
American And British Advice
In the last ten years or so there has been much activity, both official and scientific, on both sides of the Atlantic on the subject of nutrition. In the USA, a Senate Select Committee on Nutrition and Human Needs issued a report in 1977. Called Dietary Goals for the United States, that report suggested that food habits could prevent cancer. It recommended eating more fruit, vegetables and whole grains and less fat. Two years later, in 1979, the National Cancer Institute issued its own advice on eating habits to the public. The recommendations were to eat ample amounts of fruit and vegetables, to cut back on fat, drink only moderate amounts of alcohol and eat more foods that contained fibre.
In 1982 a Committee on Diet, Nutrition and Cancer presented its conclusions. Their most general conclusion was that what we eat does seem to affect our chances of getting cancer, especially particular kinds of cancer. The Chairman of the Committee said that this meant that '... by controlling what we eat we may prevent diet-sensitive cancers - possibly an easier task than eradicating them after they have taken hold. An ounce of prevention ... may be on the horizon.' That 'ounce of prevention' was:
In the UK what is popularly known as the NACNE report (the National Advisory Committee on Nutrition Education) in 1983 recommended that within the next ten years it should like to see people:
What This Book Tells You
This book looks at the various elements of food that can help us to prevent cancer. In each chapter we will examine the forms of cancer that the food element can help to prevent and then detail the amounts you will need for protection to become effective. We'll look at the best ways of fitting this into your diet and, for the sceptic, look at the advantages and disadvantages of the element itself.
One of the most exciting developments in nutrition has been findings, reported from around the world, about vitamin A. More than a dozen studies have linked diets rich in vitamin A to a surprising amount of protection against some forms of cancer.
In Norway, scientists found that men in whose diet vegetables rich in vitamin A figured prominently had only one-third the lung cancer rate of those eating little of these foods.
In Chicago, only two cases of lung cancer were discovered among five hundred men, including some smokers, who ate many fruit and vegetables rich in vitamin A. That was only one seventh the number of cases found in five hundred other men who ate few of these foods.
In Japan, the story was the same. Researchers found thirty per cent fewer cases of lung cancer among people who ate vegetables rich in vitamin A every day. Those who eat vegetables every day also had lower rates of stomach cancer.
Many cancer scientists are already convinced that we should be eating more foods rich in vitamin A. Studies show that it offers protection from cancer in 8 different organs. The evidence is strongest for cancer of the lung, stomach, or oesophagus. Research also ties vitamin A to protection from cancers of the mouth, colon, rectum, prostate, and bladder. There is less evidence here than for lung, stomach and oesophageal cancer. But there is enough to merit our attention.
Which Kind Of Vitamin A?
'Vitamin A' is a general term that refers to three kinds of substances that supply the body's needs for this nutrient. For many of the body's functions that need vitamin A, any form will do. But, as things stand right now, it seems that only some kinds of vitamin A may protect you against cancer. The three kinds of vitamin A in food are:
Carotene is the form of vitamin A that is linked most strongly to protection against cancer. Of course, one's natural reaction would be to take a vitamin A pill. But vitamin tablets usually do not use carotene or retinol. They generally contain a synthetic form of vitamin A called vitamin A palmitate. Little research has been done on the ability of this kind of vitamin A to provide protection against cancer. Scientists do not know if it has any value in preventing cancer. Secondly, the kind of vitamin A usually contained in capsules or tablets can be toxic if taken in very high doses. And in a later section we'll be looking at this possibility in greater detail.
How To Get Your Vitamin A
The best method, obviously, is to eat fresh fruit and vegetables daily. We must pay greater emphasis to the fruit and vegetables that are rich in carotene, the most important kind of vitamin A in plant foods.
Carotene In Fruit And Vegetables Per Average Serving
Low
Apples
Bananas
Cabbage
Cauliflower
Celery
Cherries
Cucumbers
Grapes
Grapefruit
Iceberg lettuce
Lemons
Limes
Oranges
Pears
Pineapple
Potatoes (white)Medium
Brussels sprouts
Green beans
Green pepper
Peas
Yellow sweetcorn
WatermelonHigh
Apricots
Asparagus
Broccoli
Cantaloupe
Carrots
Cos lettuce
Dark green leafy vegetables
Kale
Mangoes
Peaches
Pumpkin
Spinach
Sweet potatoes
Tomatoes
The table will help you in selecting the best sources of carotene. Vitamin A is measured in micrograms and the technical term is 'retinol equivalents' a composite of the different elements of the vitamin. The vitamin A activity of beta carotene is part of the retinol equivalent. You will see micrograms quoted on all food labels. The recommended intake of vitamin A in the UK for men and women is 750 micrograms of retinol equivalent a day. In the USA it is higher, at 1000 micrograms.
Colour Is The Clue
Colour is sometimes the key to assessing the amount of carotene in fruit and vegetables. Deep green and yellow vegetables are usually very good sources of vitamin A. But paler versions of the same foods are not. For instance:
Here is my favourite piece of Vitamin A trivia: frozen chopped broccoli has one third more vitamin A than the frozen spears. I am willing to bet that the leaves in the chopped version make the difference. Their deep green colour is a sure sign of vitamin A!
Other foods contain significant amounts of this vitamin. Meat, poultry and fish contain vitamin A, as do dairy products and eggs, but it is not known whether the vitamin A in most animal foods has any value in cancer prevention. That is why we should concentrate on fruit and vegetables.
It's Easy To Do
For decades, nutritionists have recommended that we eat four or more servings of fruit and vegetables each day. It is a good idea to ensure that at least two to three of these servings are rich in vitamin A. I try to eat a fruit or vegetable rich in vitamin A at every meal. Here are a few simple ways to get your vitamin A intake:
Of course, there are more exotic approaches too. How about a high-carotene pizza using broccoli, green beans and/or green pepper for 'extras?' Or learning to cook in a wok? Stir-fried vegetables can be a novelty, and they are healthy if you use only small amounts of oil.
Proclaim one or more nights of your week as 'vegetarian night around your home and see how delicious and healthy eating less meat can be.
Here is another tip: substitute sweet potatoes for white potatoes not just as a vegetable but in some of the many dishes made with potatoes.
Making The Most Of Our Vitamin A
If you are nutrition-minded, you probably try not to lose nutrients in cooking. But you are fortunate with vitamin A. It is tough stuff, indifferent to water, heat, and even long periods of storage. Vitamin A does not dissolve in water, so it does not leach into water used in cooking.
Water, in fact, can help us make the most of this vitamin. Cooking raw vegetables makes some nutrients more accessible to the body. Vitamin A is one of them.
Like vitamins D, E and K, vitamin A is soluble in fat. This means that your body needs fat to absorb it. Will cutting back on fat leave you without enough to absorb vitamin A? The chances are almost nil.
It is amazing how little fat your body needs to absorb vitamin A. In fact people who eat only one-fourth as much fat as the average European show no signs of vitamin A deficiency! So cutting fat down to a moderate level is not going to give you a deficiency of vitamin A. What it will do is make you healthier.
Value For Money
You may be health-conscious but understandably aware of costs as well and your reaction may well be, 'But some of those foods are expensive!' However, if you look at the price tag along with the amount of vitamin A that certain foods give you, you will realize that you can choose foods that give you very good vitamin A value for your money.
You have only to look at the table to see that a few ounces of dried apricots will give you all the vitamin A you need in a day. Spinach is another good source, cost-wise.
Vitamin A Content: mcg in 100 grams (3 1/2 ounces)
100g (3 1/2 oz) .......... Micrograms
Carrots, old ............ 2000
Spinach .................. 1000
Sweet potato ........... 670
Apricots .................. 600
Watercress .............. 500
Mango ..................... 200
Tomatoes ................. 100
Peas, fresh or frozen ... 50
More Benefits Of Fruit And Vegetables
I would tell you to eat more fruit and vegetables even if I didn't believe that their carotene has anti-cancer potential, for these foods do much more for you. With the exception of avocados and coconut, fruit and vegetables are admirably low in fat. The low rates of breast and colon cancer among people who eat low-fat diets tell us that eating more low-fat foods should help to protect us from these forms of cancer.
Apart from the unique coconut (high in saturated fat), fruit and vegetables lack the notorious threesome that fuels heart disease: saturated fat, cholesterol, and sodium. Another plus in fruit and vegetables is dietary fibre. There are different kinds of fibre, just as there are different kinds of vitamin A. Fruit and vegetables contain a type of fibre called pectin. When eaten in large amounts pectin helps to control blood cholesterol. Six or more servings a day are probably needed for such an effect.
Pectin, as well as other kinds of fibre in fruit and vegetables, also helps to control the blood sugar level. This is a help to diabetics. New diabetic diets often call for six or more servings of fruit and vegetables. Even those of us who do not have diabetes may benefit from fibre's effect on blood sugar. After a meal low in fibre, the blood sugar can rise sharply, then fall abruptly. Fatigue, hunger, and irritability can set in when this happens. The fibre in fruit and vegetables can help to prevent fluctuations in blood sugar levels and thus prevent these symptoms. We will talk more about fibre in a later chapter.
Are There Hazards?
No doubt about it, too much vitamin A can spell trouble. But it depends on which form of vitamin A you consume. The carotene in fruit and vegetables cannot make you sick. However, eaten in large amounts, it can cause a discolouring of the skin because the carotene can be deposited in it. This yellowing of the skin is the only symptom. It usually will go away within a few weeks of lowering carotene intake. There is no known harm from this condition.
If you take vitamin A pills, however, a very high intake may cause a toxic reaction. The classic symptoms are headaches, bone pain, loss of appetite, skin rashes, fatigue, and irritability. It is not possible to say exactly how large a supplement is required to cause an overdose. One person might develop toxic symptoms from the same dose that another can tolerate. Symptoms usually do not develop for months or years.
Reports of toxic effects usually involve high doses, about fifteen times the recommended intake. But to be cautious, several scientific committees in the USA have warned against adult doses higher than 7500 retinol equivalents a day, except when severe deficiency of vitamin A exists. Children and infants, of course, cannot tolerate nearly as much as adults.
When an over-dosage does occur, the symptoms usually subside after the offending pills are stopped. High doses of vitamin A supplement are prescribed to treat some skin disorders, such as psoriasis. In such cases, your doctor's advice should be followed.
Animal Sources Of Vitamin A
Technically one could suffer from an excess of vitamin A derived from meat and dairy products. But the only way to suffer an overdose is to eat lots of liver. There are stories of vitamin A reactions in the arctic explorers who ate polar bear liver, a rich source of this vitamin. Of the commonly available forms, beef liver has the highest content of vitamin A, about five times that found in chicken liver and four times that of pork liver. But you would still need to eat a great deal of these every day to suffer from a reaction. To give you a small indication -one small slice of liver, 6 1/2 X 2 1/2 inches in size, would give you 15,000 retinol equivalents of vitamin A and this eaten daily consistently might pose a risk to some adults.
This might also be possible if you ate 16 chicken livers every day. So the possibility of suffering an overdose from an excess of vitamin A derived from meat is really quite slim. In any case it is not clear whether these products contain the kind of vitamin A that have any value in preventing cancer.
There are studies linking milk consumption with reduced chances of getting stomach cancer. And milk contains vitamin A so it may suggest a role for animal vitamin A in cancer prevention. But many animal foods with vitamin A have serious drawbacks:
It is time to rewrite our nutrition textbooks. The textbooks of yesterday tell us that vitamin C prevents scurvy. They speak of its role in healing wounds. They say that vitamin C helps in the formation of collagen, which holds cells together.
But an update is in order. It's not that vitamin C does not do these things, but rather that it does much, much, more. It may well help to prevent cancer. Scientists have found that cancers of the stomach and oesophagus are less common among people who eat diets rich in vitamin C. Over 20 years ago a Dutch expert noted that people who developed stomach cancer were less likely to have been eating citrus fruit (which contains vitamin C) than those who did not have cancer. Later reports from around the world confirmed that foods which contain this vitamin could offer protection against cancer. It is curious to note that there may be a connection between the wide use of fresh fruit and vegetables and the lower rates of stomach cancer in the United States.
Stomach cancer was common in the United States at the turn of the century, when some fruit and vegetables were available only seasonally. Now they are available year-round, and many are rich in vitamin C. Stomach cancer is also no longer common, although the disease does remain a major health problem in some parts of the world.
How Vitamin C Protects Us
This vitamin acts as a kind of shield in preventing the formation of cancer-causing substances in the body. Nitrites in foods can turn into cancer-causing nitrosamines during cooking or digestion. Bacon has a particularly bad record after cooking.
Laboratory scientists know that nitrosamines can be created by allowing certain chemicals to come in contact with each other. When vitamin C is added to the chemical mixture that normally results in nitrosamines, fewer of them are formed. In some cases, vitamin C has completely blocked the formation of nitrosamines.
Can the same thing happen in our bodies? Studies around the globe suggest that the answer is yes. Researchers also know that Western Europeans and Americans have fairly low rates of stomach cancer. These countries enjoy access to a variety of fruit and vegetables. In the United States, the chances of developing oesophageal cancer dropped as the amount of fruit and vegetables eaten went up.
Fruit and vegetable intake has been found to be low in some regions where stomach and oesophageal cancer are rampant. Iranians living by the Caspian Sea, for instance, have alarming rates of oesophageal cancer, and fruit and vegetables are almost absent from their diet.
Another Role For Vitamin C
Scientists have known for decades that vitamin C can block the chemical reaction called oxidation. Oxidation is the process that causes food to become rancid. Substances that prevent oxidation are called antioxidants. Until recently, no one realized that antioxidants might help protect against cancer. But they very well may. Scientists now believe that some chemicals cause cancer only if oxidized. By preventing oxidation, vitamin C may cut down on our exposure to cancer-causing chemicals.
Foods rich in vitamin C are generally popular with everyone from babies to adults. It is not difficult to ensure the recommended intake of 30 milligrams vitamin C a day - if you look at the table you will see why. Animal foods are not listed because they supply minimal amounts of the vitamin. Fruit and vegetables are the best source.
Vitamin C In Average Serving Of Fruit And Vegetables
Low *
Apples
Celery
Cucumber
Grapes
Pears
Plums
PumpkinMedium **
Apricots
Bananas
Beetroot
Carrots
Cherries
Corn
Dark green leafy vegetables
Kale
Mangoes Peaches Potatoes (white)
Spinach
WatermelonHigh ***
Asparagus
Blackcurrants
Broccoli
Brussels sprouts
Cabbage
Cantaloupe
Cauliflower
Grapefruit
Green pepper
Kohlrabi
Lemons
Limes
Oranges
Peas
Pineapple
Strawberries
Tangerines
Tomatoes* Low: Less than five milligrams (mg)
** Medium: Five to 20 mg
*** High: More than 20 mg
Adapted from the work of Committee on Diet, Nutrition, and Cancer, National Academy of Sciences USA, 1982.
If you are wondering what qualifies as a serving, here are some guidelines. For juices, think of 200ml (six ounces) as a serving. For vegetables a rough guide would be between 100 grams (4 oz.) and 150 grams (5 oz.), depending on the kind of vegetable.
For most fruit, such as oranges, bananas, or apples, one whole fruit is one serving. For larger fruit such as grapefruit, half of one fruit is one serving. In the case of very large fruit, such as melon, you can consider one cup of the fruit, diced, as one serving.
Nutrition experts have always recommended four or more servings a day of fruit and vegetables. I think that at least two, and preferably three of these, should be foods supplying moderate to high amounts of vitamin C. I try to eat a food rich in vitamin C at every meal. It is not hard. I can hardly start the day without my orange juice. So that is my first suggestion. Grapefruit juice is also a fine choice. Here are some other tips that work for me.
Vitamins A And C Often Go Hand In Hand
If it seems that eating to prevent cancer is getting complicated, rest assured that it does not have to be. There are quite a few foods that are good sources of both vitamins A and C. You might call them the fruit and vegetable all-stars:
Many of these foods complement each other in cooking. I sometimes mix apricot nectar with orange juice to give a not-too-sweet breakfast beverage. That way I start my day right, with both vitamins A and C. I cannot resist pointing out that most of these foods rich in vitamins A and C are pleasantly low in calories too.
Handle With Care
Vitamin C is very sensitive. Heat, light, and oxygen can destroy it. In fact, some loss of vitamin C in food just cannot be prevented. With a little effort, though, losses of the vitamin can be kept to a minimum. Here are the rules:
It is not always possible, of course, to follow these rules, but when it is, do so. The vitamin will also hold up better if not heavily exposed to light.
About Frozen Foods
All of this talk about losing vitamin C must make you wonder if any of it is left in processed foods. The answer is: it depends. In some cases, the ability of the food industry to preserve the vitamin C in food is no less than amazing. In other instances, though, it seems that processors are not trying hard enough.
My favourite example is frozen orange juice concentrate. It contains hardly a milligram less vitamin C than the oranges that it hails from. The juice processors have perfected their trade so well that it is almost an art. Many other frozen foods do lose some vitamin C during the trip from field to supermarket. But their fresh counterparts are likely to do so, too, during storage and cooking. So, though fresh, raw vegetables usually have the most vitamin C, once cooked, their C content may be on par with that of frozen foods.
If you observe the rules on preserving the vitamin C in foods, your fresh, cooked vegetables may retain more vitamin C than frozen ones.
Is There Vitamin C In That Can?
For canned fruit and vegetables, the story is not so good. Canned foods often have less vitamin C than frozen or fresh foods. The vitamin C leaches into the water used in packing.
So even though a canned food might have a lower cost per pound than the fresh or frozen version of the same item, it is not necessarily the best buy. If the canned version has only half as much vitamin C as the frozen, for instance, it actually can cost more to get 20 milligrams of vitamin C from it.
I do not want to imply that canned foods have no nutritional value. Nor do I mean to say that canned foods should never be used. But nutritionally, frozen foods are a better buy. When in season, fresh foods are often a better buy, too. And fresh or frozen foods usually have less salt - a big plus. If you eat fresh, uncooked foods, then of course, there is no loss of the vitamin. To give you an idea of how cooking affects vitamin C, I've put together the following chart.
The Vanishing Vitamin
Vitamin C Lost During Cooking And Storage
Green Beans
1 cup, raw 21 mg
1 cup, fresh, cooked * 13-15 mg
1 cup, frozen, cooked * 7 mg
1 cup, canned 5 mgPeas
1 cup, raw 39 mg
1 cup, fresh, cooked * 32 mg
1 cup, frozen, cooked * 21 mg
1 cup, canned 14 mg* Boiled just until tender, in a small to moderate amount of water.
Remember: the vitamin C that remains in frozen or fresh foods can be destroyed by too much exposure to heat, light, and large amounts of cooking liquid. But a little effort can prevent unnecessary loss.
A Word To Smokers
Smokers - take notice of three important facts.
We do not know quite why, but research has shown that smokers have anywhere from 30 to 50 per cent less vitamin C in their blood than nonsmokers. And it is not because smokers take in less vitamin C.
They get as much of the vitamin as nonsmokers.
For years we have known that the amount of vitamin C in the blood decreases with age. But a recent study found that smokers aged 20 to 39 had less vitamin C in their blood than nonsmokers aged 40 to 64. One reason could be that smokers excrete more vitamin C, but scientific evidence points to the contrary - they excrete less than nonsmokers.
Apparently smokers use up more of the vitamin C they take in. Their body may be using extra vitamin C in an effort to counteract the harmful substances in tobacco smoke. Whatever the reason, it makes good sense for smokers to ensure a good intake of vitamin C.
If you have more than two or three drinks a day and smoke as well, you should pay even closer attention to your vitamin C intake.
Those who smoke and drink heavily have a much higher risk of mouth and oesophageal cancer. Since vitamin C is linked to lower rates of these two cancers, this is another reason for those who smoke and drink to include more vitamin C in their diets.
The Controversy Over Vitamin C Supplements
The studies that tie vitamin C to cancer prevention usually link foods containing vitamin C rather than the vitamin itself to reduced risk of cancer. There is always the possibility that it is something else in these foods, rather than the vitamin C, that is protecting our health. If this is the case, people who take a vitamin C tablet, rather than eat vitamin C-containing foods will miss that unknown protective substance. I think that it is probably the vitamin C itself that is protective, though I also believe that other substances in these same foods may have anti-cancer properties.
Ideally we should get our vitamin C from natural foods, but some people just don't care for vegetables. And some parents have tried, but failed, to convince children to eat more fresh fruit and vegetables.
I simply cannot see the point of withholding a moderate vitamin C supplement when this is the case. I think it is unscientific to advocate a diet that contains 200 mg of vitamin C a day, yet oppose a supplement of this amount for those people who do not eat foods rich in vitamin C.
There has been a continuing debate about the value of vitamin supplements and there is a fair amount of opposition to them. There is also the feeling that high doses of supplements can have adverse reactions. My research has shown that it is quite true that in high doses some nutrients can cause more side- effects than some drugs.
For example, nicotinic acid (a version of the vitamin niacin) when taken in high doses can act as a drug. But when we come to vitamin C the research has led me in a different direction.
All the evidence points to the conclusion that this vitamin is one of the least toxic substances in the pharmacy. Generally the dosage of vitamin C that has been reportedly responsible for causing problems in some people is far in excess of the normal level you would get in a diet rich in fruit and vegetables. But even at high doses, the toxic effects of vitamin C appear to be the exception rather than the rule.
There are four problems that have been linked to very high doses of vitamin C:
1. The Kidney Connection
It is true that high doses of vitamin C may speed formation of kidney stones, and this may occur among people who are especially prone to this condition. However, not everyone who tends to develop kidney stones knows that they are vulnerable. How much vitamin C did it take to bring on kidney stones or the early signs of stones? According to a commentary published in the New England Journal of Medicine this problem has been seen in people taking four or more grams of vitamin C every day.
The same process that makes kidney stones more likely to form may also worsen gout. People who are susceptible to gout should also take note of these findings.
2. Destruction of vitamin B-12
It is also possible, but probably not likely, that vitamin C may destroy some of the vitamin B-12 in food. A few years ago, two scientists put together some laboratory equipment to mimic digestion. They reported that under these 'test-tube' conditions, a 500 mg supplement of vitamin C destroyed a high percentage of the vitamin B-12 in food.
When another scientist studied this issue in human subjects, the results were different. This researcher examined vitamin B-12 levels in the blood of people who had been taking at least 500 mg of vitamin C daily. He found that only three of the ninety people tested had low levels of vitamin B-12. These three, all between fifty and sixty years of age, had been taking a minimum of 1000 mg of vitamin C with each meal for more than three years.
There is one more fact to note regarding the effect of vitamin C on vitamin B-12. Scientists believe that less B-12 will be destroyed if the vitamin C is taken two or more hours after eating.
3. Complications from lack of the enzyme G6PD
The abbreviation G6PD stands for glucose-6-phosphate dehydroge-nase.
As its name implies, this enzyme is used in metabolism of glucose, a type of sugar. In the United States a man who had been given 80 grams of vitamin C for two days as a treatment for burns died a few weeks later. It emerged that he suffered from a G6PD deficiency.
Although he had been given an enormous amount of vitamin C, scientists are concerned that others with G6PD deficiency may be sensitive to smaller doses. If you have this condition, you should be aware of this concern.
About ten per cent of black American men have mild G6PD deficiency. A smaller percentage of black women are affected, as are a few Caucasians. Screening for this condition is possible.
4. Vitamin C and Prescription Drugs.
If you take any of the following prescription drugs, consult your doctor before taking a vitamin C supplement, because it may occasionally interfere with their action.
Pregnant women should also take only as much vitamin C as prescribed by their physicians.
Beyond the Cancer Question
I would drink my orange juice and eat my green pepper even if it weren't for research linking vitamin C to prevention of cancers.
Some of my reasons are similar to those for advocating eating more fruit and vegetables that supply carotene. This is because plant foods rich in vitamin A and vitamin C are also low in saturated fat and sodium. Furthermore those that contain vitamin C are cholesterol-free. And they provide small to moderate amounts of dietary fibre. Eaten in large amounts, the fibre in these fruit and vegetables helps to lower blood cholesterol levels.
There is more. Vitamin C is rarely recognized for its role in iron absorption. Yet we have known for many years that vitamin C helps the body to absorb iron.
Because the body absorbs only about ten per cent of the iron taken in, factors that increase iron absorption are just as important as iron rich foods. In fact, some scientists believe that increasing absorption of iron, rather than boosting iron intake, is the key to improving iron nutrition. They may be right on target.
At moderate levels - such as 50 mg to 100 mg - vitamin C has been found to improve iron absorption by as much as 50 per cent. Higher doses may result in even higher absorption. Vitamin C helps the body absorb iron in foods that are eaten at the same meal. The vitamin C in breakfast foods, for example, has little or no effect on the iron in foods eaten at lunch or dinner.
For some people, however, this is not good news. A small number of people have a condition that causes them to retain too much iron, which accumulates in various organs, causing health problems.
People who have this condition should consult their doctor for advice about diet.
The NACNE experts agree that 'increased vitamin C intake will also promote iron absorption.' But they have another comment to make: 'the debate continues about the usefulness of large doses of vitamin C in the prevention of a variety of disorders including the common cold. The doses suggested are pharmacological rather than nutritional and do not find favour with expert bodies who assess the evidence.'
I would love to tell you that vitamin C will protect you from heart disease. But I cannot, because I am not at all convinced by these claims.
I have looked carefully at the evidence that vitamin C lowers blood cholesterol levels. But I found other studies in which vitamin C supplements appeared to have raised the cholesterol level. Some studies show no difference. I really do not hold out much hope for an effect here.
But what more can you want from vitamin C? It does not have to play a role in the prevention of every disease in order to be taken seriously.
Vitamin C is as important today as it was two centuries ago, when the mysterious disease called scurvy threatened the lives of sailors who spent months without fresh fruit and vegetables. It is hard to disagree with the advice to make more room for this familiar vitamin in our diets.
For decades, nutritionists viewed fibre as all but worthless. It did not even qualify as a nutrient, because its absence didn't cause the deficiency diseases that result when diets are inadequate in protein, vitamins, or minerals. They believed fibre served no useful purpose other than to prevent constipation.
But during the past decade, fibre has come into its own. It is now the focus of intense research. It is now known that fibre plays a role in regulation of blood cholesterol and blood sugar and may even help with weight control.
It is likely that fibre can help to prevent cancer. We are now advised to eat whole grain foods every day. These foods are a good source of fibre. Grains that have been refined - such as white flour - contain little fibre.
Fibre: What It Is
Fibre is a general term for an assortment of substances in food that are not digested in the small intestine. With one exception, all forms of fibre are carbohydrates. Fibre in food has several forms:
There are basically two kinds of fibre: soluble and insoluble. As their label implies, the soluble fibres are those that dissolve in water. Pectins, gums, and mucilages fall into the soluble category. Insoluble fibres are those that do not dissolve in water. Cellulose, hemicelluloses, and lignin are insoluble fibres.
Both soluble and insoluble forms of fibre play important roles in preventive medicine. Current research suggests, however, that only the insoluble fibres help to prevent cancer.
The insoluble fibres create bulk in the digestive tract. The more bulk there is, the less room for harmful chemicals that might cause cancer. The soluble fibres do not give bulk, but they do have other virtues, which we'll discuss later in the chapter.
The best source of the bulk-producing insoluble fibres is whole grain foods - especially bran. Studies worldwide link whole grain foods to lower risk of colon cancer. Studies on animals back up these results. In animals, wheat bran has, more often than not, shown an ability to help protect against colon cancer.
How Much Fibre Should We Eat?
The average British diet today has about 20 grams of fibre. This is almost half the amount that was generally eaten during the war, when it was 32 grams to 40 grams of fibre per day. The NACNE report recommended that "intakes should be increased to an average of about 30 grams of dietary fibre per day for adults. Cereal fibre, in particular, should be increased ..." The experts also suggest that the fibre might be best derived from foods, and not from dietary fibre preparations or foods to which bran and other fibres have been added. This view is supported by the report of the experts on the Nutritional Aspects of Bread and Flour. They believe that fibre from wheat, as opposed to that from other sources, has distinctive properties - especially in its action on the colon.
Wheat bran is the best source of fibre. Four ounces of 100 per cent whole bran cereal has about three times as much fibre as a slice of whole wheat bread.
You can add fibre to your diet in several ways. Starting the day with a bran cereal is not a bad idea. You can substitute a small amount of flour used in baking with bran. Because bran is so rich in fibre, even a small amount counts. As a general rule, try replacing about one-third of the flour in a recipe with an equal amount of bran.
When baking with bran, it is best to soften the bran in liquid before baking. Try to combine the cereal with a liquid ingredient in the recipe.
Be Creative With Cereals
Shredded wheat is another excellent source of wheat fibre and there are many ways of enjoying it.
Oats are another versatile whole grain food. The instant oats, which are steamed at the factory, have added sodium, but the "quick," or old-fashioned oats do not. Hot cereal is the most obvious use, but there are many ways to enjoy them.
Whole Grain Ideas
Probably the simplest way to add whole grain fibre to your diet is to choose a whole grain cereal for breakfast. But you should also consider the sugar content of cereals as many breakfast cereals are high in sugar. The table will give you a good idea of both fibre and sugar content:
Rating The Breakfast Cereals
Source: McCance and Widdowson's The Composition of Foods, A.A. Paul, D.A.T. Southgate, Medical Research Commission Special Report No. 297, 1978, 1980.
Of course, there are whole grain foods other than cereals. You could choose some that go well with lunch and dinner, or make good snacks:
All of these foods are moderate sources of insoluble fibre.
If you generally eat a cereal for breakfast, it will be relatively easy to choose one that is rich in fibre - and this will not cost too much.
If you like natural bran, it may actually be a better buy at a health food store, where you could buy in bulk.
A Matter Of Milling
You may be surprised to see brown rice and whole meal bread described as only moderate sources of fibre. These foods contain less fibre than is commonly believed.
Brown rice, for example, has only a moderately higher fibre content than white rice. The difference amounts to about 1 1/2 grams per half cup of cooked rice.
Wholemeal bread has more fibre than brown rice, yet less than many people assume. It is a moderate source of fibre, but not one of the highest. In general, coarse wheat products have more fibre than breads. Bran and shredded wheat also have a greater beneficial effect partly because of the bulk they create in the digestive system.
Grinding wheat into flour reduces its ability to create bulk in the digestive tract. A finely ground source of fibre - such as whole meal bread - does not give as much bulk as bran.
Because of this, foods made from whole grain flour do not have as much laxative power as bran and other coarse forms of wheat. It is possible that foods made from finely ground whole grains also have less value in preventing cancer. The table shows you the amounts of fibre in different kinds of flour and breads made from them:
Dietary Fibre (In Grams) Per 100 Grams
Flour *
White .......... 3.0
Brown ......... 7.5
Wholemeal ... 9.6Bread
White .............. 2.7
Bread Brown ... 5.1
Wholemeal ....... 8.5Source: Paul and Southgate, 1978.
* White, brown and whole meal flours correspond to flours of approximately 72%, 85% and 100% extraction.
Baking With Fibre
Baking with whole meal flour instead of white is another way to boost your fibre intake. In yeast breads making this substitution poses no problem.
But making cakes and biscuits with whole meal flour increases the amount of fat needed for good texture. Cakes and biscuits made with whole meal flour require about one and one-half to twice as much fat as those made with white flour. And some people find their heavy texture unappealing.
One way to solve this problem is to use half white flour, and half whole meal flour when baking. This should hold down the amount of fat needed.
If you are interested in the extra minerals in whole grain flour, rather than its small amount of fibre, there is another option. Use one part wheat germ and three parts white flour for each cup of flour in a flour for your recipes. You'll get roughly the same nutrients as in whole wheat flour, excluding, of course, its fibre content.
More Foods With Fibre
Fibre comes in other foods, which also have the bulk-producing ability of whole grain food.
Among beans, fruit, and vegetables, the best sources of insoluble fibre are:
I have learned to use peas in both hot and cold recipes; I add them to meat dishes and stews as well as to salads. I have also found that for a change of pace, beans make a nice salad.
The following foods have less insoluble fibre than the other foods quoted earlier. But they still have respectable amounts:
Only plant foods contain fibre - there is none in animal foods, fats, and oils.
How Much Is Enough?
It makes good sense to eat more whole grain foods and more fibre. As mentioned earlier, experts would like to see a daily intake of 30 grams of fibre a day.
This does not mean that all the cereals in your diet must be whole grain, or that every fruit and vegetable you choose must rate high for fibre.
My advice is to make about half the grains in your diet whole grains. I am not with those who despise any food made from refined grains.
True, refined grain foods contain less of certain minerals than whole grain foods. And they have less fibre, though in some cases (such as brown versus white rice or whole meal pasta versus white pasta), the differences are small.
But this is not to say that foods made with white flour are worthless. They provide respectable levels of protein, iron, and certain vitamins. And they are low in fat and cholesterol and often low in sodium.
In short, there is something good to be said for both whole grain and refined grain foods. Choosing a reasonable balance between the two would be sensible.
If you want to estimate your fibre intake, consult the charts that follow. The first gives the total fibre content of foods; the remaining two divide fibre into the two basic types: insoluble and soluble.
Total Fibre Content Of Food
(Soluble And Insoluble)
1 gram
Almonds, 10
Apricots, 2 medium
Asparagus, 1/2 cup
Aubergine, 1/2 cup
Peanuts, 10
Rice, brown, 1/2 cup2-4 grams
Carrots, 1/2 cup
Pear, 1 small
Strawberries, 1/2 cup
Potato, 1 small5 grams or more
Bran cereals, 1/2 cup
Peas, 1/2 cup
Rolled oats, 1/2 cup
Shredded wheat cereal,
2 large biscuits
Insoluble Fibre Content Of Foods
Low *
Apricots, 2 mediumAsparagus, 1/2 cup
Aubergine, 1/2 cup
Banana, 1 smallBean sprouts, 1/2 cup
Bread, french, 1 slice
Bread, white, 1 sliceBeetroot, 1/2 cup
Carrots, 1/2 cup
Cauliflower, 1/2 cup
Cherries, 10
Cucumber, 1/2 cup
Egg noodles, 1/2 cup
Grapefruit, 1/2
Grapes, 10
Kale, 1/2 cup
Lettuce, raw, 1/2 cupOnions, 1/2 cup
Peach, 1 small
Pineapple, 1/2 cup
Radishes, raw, 1/2 cup
Rice, white, 1/2 cup
Roll, dinner, 1
Spaghetti, 1/2 cup
Swede, 1/2 cup
Tangerine, 1 medium
Turnip, 1 mediumMedium **
Apple, 1 smallBeans, lima, 1/2 cup
Beans, pinto, 1/2 cup
Beans, green, 1/2 cupBread, white, 1 slice
Broccoli, 1/2 cup
Brussels sprouts, 1/2 cup
Courgettes, 1/2 cup
Oats, whole, 1/2 cup
Pear, 1 small
Plums, 2 small
Potato, 1 small
Rice, brown, 1/2 cup
Rye crispbread, 3
Strawberries, 3/4 cup
Summer squash, 1/2 cup
Tomatoes, 1/2 cup
Whole wheat cereal flakes, 3/4 cupHigh ***
Beans, kidney, 1/2 cup
Beans, white, 1/2 cup
Blackberries, 1/2 cup
100% Bran cereal, 1/2 cup
Parsnips, 1/2 cupPeas, 1/2 cup
Shredded wheat,
2 large biscuitsUnless otherwise indicated, all values for vegetables and pasta reflect fibre content of the cooked product.
1/2 cup is equivalent to 4 oz (100g)
Soluble Fibre Content Of Foods
Low *
Asparagus, 1/2 cup
Beans: kidney, butter, 1/2 cupBean sprouts, raw, 1/2 cup
Bread, french, 1 slice
Bran, 1/2 cup
Cauliflower, 1/2 cupCherries, 10 medium
Cucumber, raw, 1/2
Grapes, 10
Lettuce, raw, 1/2 cup
Oats, whole, 1/2 cup
Parsnips, 1/2 cup
Peach, 1 medium
Pineapple, 1/2 cup
Radishes, raw, 1/2 cupMedium **
Apricots, 2 medium
Aubergine, 1/2 cupBanana, 1 small
Beans, green, 1/2 cup
Beetroot, 1/2 cup
Blackberries, 1/2 cup
Brussels sprouts, 1/2 cup
Grapefruit, 1/2 cup
Kale, 1/2 cup
Onions, 1/2 cup
Pear, 1 small
Strawberries, 3/4 cup
Swede, 1/2 cup
Tomatoes, 1/2 cup
Turnips, 1/2 cupHigh ***
Apple, 1 small
Broccoli, 1/2 cupCarrots, 1/2 cup
Courgettes, 1/2 cupPeas, 1/2 cup
Plums, 2 small cup
Potato, 1 smallTangerine, 1
* Low. 0.5 grams or less
** Medium: 0.6 to 1.0 gram
*** High: 1.1 grams or more
Other wheat products such as whole meal or white bread and pasta are insignificant sources of soluble fibre. Brown and white rice also contain very little soluble fibre.
Unless otherwise indicated, classification of vegetables is based on values for the cooked product.
Points To Remember
There is one reason not to go all out when it comes to fibre. We have known for decades that fibre can bind to minerals in food, preventing the body from absorbing them. The effects vary according to the minerals. This is what we know:
Whole grains contain more zinc and copper than refined grains, so this may offset any loss of these minerals resulting from the fibre.
It is best, however, to take a moderate rather than extreme approach to the fibre content of your diet.
Minerals are also affected by the phytic acid in whole grains. Also called phytate, it can tie up minerals.
Fortunately, we know that yeast can destroy phytate, so whole grain breads made with yeast, do not pose a problem. It is only the people eating enormous amounts of unleavened bread who should be aware of the action of phytic acid.
Fighting Fat With Fibre
Fibre is a healthy ally for people wishing to lose weight. It not only helps to reduce the absorption of calories from carbohydrates, but also those from protein and fat. Studies show that people absorb one to three per cent fewer calories when eating a high-fibre diet.
Most of us gain weight slowly, at the rate of an extra pound or two per year. For a woman needing 1800 calories a day, a one per cent fall in calories absorbed would mean a loss of two pounds per year. A three per cent reduction in calories absorbed translates into six fewer pounds per year.
There's only one catch. These findings come from short-term studies. No one knows whether the body will adapt to a high-fibre diet so that eventually just as many calories are absorbed.
Researchers studying fibre's effects have reported that their subjects have complained about the "large" quantity of food they were asked to eat. Little did they realize that the high-fibre diets contained no more calories than the low-fibre diet. This is because fibre creates a feeling of fullness. In the stomach, fibre swells with water, and this may help curb the feeling of hunger.
Some scientists also believe that high-fibre foods help with weight control because they take longer to chew.
A high-fibre diet based on whole grains, fruit, and vegetables is likely to be nutritionally sound. That is more than can be said for so many of the "miracle" weight-loss diets that come along every year.
More Benefits Of Fibre
Fibre is now known to benefit the following conditions:
Diverticulosis is a common condition among older people, when the intestines develop little pouches. Food can get caught in these pockets, and this results in inflammation and pain.
Doctors used to treat this problem with a low-fibre diet. But much to their surprise, they have learned that a high-fibre diet usually gives much better results. In general, patients are asked to add wheat bran to their diets.
Soluble fibre helps to control blood cholesterol and blood sugar.
It does not lower blood cholesterol nearly as much as saturated fats and cholesterol raise it. But a diet rich in fruit and vegetables (beans and oats are also good sources) has a mild cholesterol-lowering effect. Lower blood cholesterol, of course, means lower rates of heart disease.
These soluble forms of fibre have also revolutionized the treatment of diabetes. New research has shown that a high-fibre diet helps diabetics control their blood sugar better. Their insulin requirements often drop on a high-fibre diet. Changes in insulin doses should be made only on a doctor's instructions. Fibre's ability to keep the blood sugar under control may very well help people who do not have diabetes. A low-fibre meal can cause the blood sugar level to rise quickly, then drop abruptly. See the table for foods high in soluble fibre.
Headaches, hunger, and irritability can set in as a result.
But fibre can guard against these symptoms by preventing sharp swings in the blood sugar level.
Dental researchers believe that whole grain foods may play a role in preventing tooth decay. Studies show that something in whole grains may protect the teeth from decay-producing acids produced by bacteria in the mouth.
Do you think of cancer as a mighty sword that can reach down and hurt any and all of us? At any time? If you do, then you should think again. Exciting new research shows that nature gives us weapons that can fight back - and they are in everyday foods. I am not talking now about the nutrients you have read about in earlier chapters, but about other substances which are not considered nutrients because their absence does not cause a deficiency disease. These substances are little-known food elements. Only a handful of research scientists are familiar with them.
Scientists call them inhibitors. In laboratory animals, these substances show an impressive ability to inhibit the cancer process.
How Cancer Inhibitors Work
A cancer agent, such as one found in cigarette smoke, might cause cancer in half of the animals that are exposed to it. But when an inhibitor is given along with the cancer-causing chemical, fewer animals will develop cancer. The inhibitor prevents the cancer-causing chemical from doing its damage.
Exactly how inhibitors work is not known. But the best theory right now has to do with an enzyme system in the body's cells. It is called the mixed function oxidase system. Scientists believe that this enzyme system may actually have the power to strip dangerous chemicals of their harmful effects.
Cancer scientists have been curious about inhibitors for a very good reason. Human studies do support the notion that certain foods help to block the cancer process. Several studies have found that people who often eat foods thought to contain inhibitors have less chance of getting cancer.
For the most part, inhibitors are linked to protection against cancer of the digestive organs. Research ties these inhibitors most strongly to reduced rates of stomach and colon cancer. Cancer inhibitors may help to explain why many people who are exposed to cancer agents never develop cancer. A good intake of cancer inhibitors may be part of the answer.
How To Protect Yourself
In the United States the Committee on Diet, Nutrition, and Cancer took a close look at research on cancer inhibitors. It then made one recommendation: that there should be an emphasis on foods belonging to the cabbage family. There is good evidence that these foods contain cancer inhibitors other than vitamins A and C.
The most common foods of the cabbage family are broccoli, cauliflower, brussels sprouts, and, of course, cabbage. Research has linked these four vegetables to reduced risk of both stomach and colon cancer. A few studies link these foods to lower risk of rectal cancer.
There are other foods in this family of vegetables. But it is not possible to say whether these other foods are also linked to lower risk of these cancers. It is reasonable to believe that these other foods are more likely than not to contain the same cancer-blocking substances. But only further research will give a firm answer.
The Cabbage Family
Broccoli
Brussels sprouts
Cabbage
Cauliflower
Chinese cabbageCollards
Horseradish
Kale
Kohlrabi
KrautMustard
Radish
Swede
Turnip
Watercress
A Family Of Many Names
The technical name for the cabbage group of foods is the Brassica family. They are also known as "cruciferous" vegetables.
The inhibitors found in broccoli, brussels sprouts, cauliflower, and cabbage are called indoles. Research on indoles is so recent that tables listing the indole content of foods are nowhere to be found.
So it is not possible to rank foods by their indole level. Also it is not known whether cooking and storage influence the indoles in these foods.
The best advice is to select the foods of this family that you like best and eat them often - perhaps once or twice a week. Remember that many of them offer other bonuses: vitamins A or C, a low fat and sodium count, and a modest amount of dietary fibre.
Putting Cabbage On The Menu
This a versatile family of vegetables. They can start out in soup or salad, be a side dish, or star in the main course in their own right.
Other family members, though, are suitable only for a specific dish. And some are only a garnish.
If you like raw broccoli, you can use it with dips and on salads. You can add it to soups - leave it in pieces or puree it. Try adding curry powder to the soup.
Cauliflower can be used in all of these ways, too. And broccoli and cauliflower go well together in both side dishes and main courses.
Cabbage, of course, can have several roles: soup, salad or vegetable accompaniment. Cabbage can be added to main dishes such as chili, or stir-fried with apples and onions for a great side dish.
Brussels sprouts are not quite as versatile - or as popular. This vegetable is best suited as a side dish, though I have seen it stuffed with cheese as an appetizer.
Two members of the cabbage family - radish and watercress - are used mostly as salad ingredients. But I have encountered both in soups, too. Another family member- the turnip - can replace potatoes in many recipes. The greens in this family- collards, kale, and mustard greens - work best as a vegetable side dish.
Cabbage Cookery
If you are not familiar with some of these vegetables, you may be interested in the following guidelines for preparing them:
Cooking times for these vegetables depends on several factors, such as their size and age. Here are some rough estimates for boiling or steaming fresh vegetables.
Remember: the sooner these vegetables are prepared after purchase, the more nutritious they will be.
Other Foods That May Help
The cabbage family is not the only group of foods that has shown potential to block the cancer process. Some other foods may have even greater ability, but the evidence for these foods is not as strong.
Some foods have inhibited cancer in studies on animals, but studies with humans have yet to be done. Other foods have been examined in only one or two experiments - too few for judgment.
Of the other foods that might contain cancer inhibitors, the evidence is best for citrus fruit. The beneficial effect has ranged from weak to potent in studies with animals. For other sources of cancer inhibitors, the research is still in its infancy.
You may like to know of other areas now being examined:
Remember: for some of these foods only one or two studies have been done. This is far too little work to justify changing your diet.
Some Unanswered Questions
Scientists are still a little cautious about the cancer inhibitors in food. They aren't totally convinced that these substances are only beneficial. The Committee on Diet, Nutrition and Cancer agreed that, on balance, the good points of the cabbage family vegetables outweigh the bad points.
The latter are generally thought of as "uncertain effects." As noted earlier, inhibitors seem to activate an enzyme system that is thought to detoxify harmful chemicals. There is some concern that this may also enhance the power of some chemicals.
Still, the scientists recommend that we eat citrus fruit, whole grain cereals and cabbage family vegetables. Obviously they think that the benefits outweigh the disadvantages. So make the cabbage vegetables a part of your diet. Eating them often, once or twice a week but not exclusively, is a moderate approach.
Putting It All Together
Up to this point, you have read a great deal about fruit, vegetables, and grains. But this is the last chapter is to deal with them directly.
It is fitting, I think, to take a broad look at these foods to see how they score when all protective factors are taken into account.
There are four elements to be considered: vitamin A, vitamin C, insoluble fibre, and cancer inhibitors. To take a simple approach to these four factors, I have devised a rating system.
I gave a food one point if it contains a moderate amount of vitamin A and two points for a high level. I used the same system for vitamin C and for insoluble fibre.
I then awarded two points to the four members of the cabbage family that appear to contain a cancer inhibitor other than vitamins A and C or fibre. I gave one point to the other foods that might have a cancer inhibitor.
The Top-Scoring Foods
When all the points were tallied, broccoli and brussels sprouts topped the list.
They were followed by some vegetables that many people eat little of: collards, kale, kohlrabi, mustard greens, and swede.
But in third place were some familiar faces: oranges, grapefruit, cabbage, cauliflower, lima beans, and spinach. Watercress also rated with this group.
Chances are that you like some of these foods. Pick the ones you like best, and continue to enjoy them.
How tempting it would be to think that there is a single solution to all our health problems. But, of course, things aren't that simple. There is, however, some evidence that minerals play a role in preventing cancer, especially the mineral selenium. More research is needed before we can draw any firm conclusions.
The Minerals In Food
Food contains a wide range of minerals. We need some of them in large amounts, while others are necessary in small quantities. The minerals we require in large amounts are termed major minerals. Those that we need less of are known as trace minerals or trace elements. The most important minerals are:
Major Minerals
calcium
magnesium
sodium
chloride
phosphorus
potassiumTrace Minerals
copper
chromium
fluorine
iron
manganese
molybdenum
selenium
zinc
Scientists know a great deal about some trace minerals, and very little about others. In relation to cancer, research has focused only on trace minerals.
Selenium and iron are the best studied of the minerals. But though there is evidence that selenium may protect both humans and animals against some forms of cancer, it is promising but yet not final. A similar view is taken of the evidence that an adequate iron intake protects both humans and animals against cancer of the upper digestive tract.
In the United States, experts could come to no conclusion about the role of some minerals in cancer prevention. These are:
Of course the last three - arsenic, cadmium and lead - are in fact, linked to high cancer rates in workers who are heavily exposed to them. But these exposure levels are, in fact, much higher than those that are found in food.
The Selenium Story
The evidence that selenium helps to prevent cancer is promising but not definitive. Research has shown, for instance, that:
One problem with these findings is clear. Scientists can rarely know whether a cancer patient has always had a low blood level of selenium. It is possible that the disease, once developed, caused a normal selenium level to drop suddenly.
Some research has yielded opposite results, showing no relationship between the selenium in the blood and the risk of cancer. But on the whole, the research on this mineral must be considered promising.
There once were concerns that selenium might promote cancer. These fears have not been supported by the most recent research. It has, however, shown that selenium can be toxic in other ways. Scientists would be reluctant to advocate a measure that will help prevent one disease but cause others instead. Some of these aspects are discussed below.
1. Supplements
Encouraged by reports linking selenium to cancer protection, people are taking supplements of this mineral. Selenium can cause health problems if taken in high doses. Fatigue and irritability, as well as brittleness or loss of hair, have been seen in patients suffering from toxic amounts of selenium. A research scientist exposed to too much selenium developed bronchitis and skin problems.
2. How Much is Too Much
According to the Food and Nutrition Board of the National Research Council in the USA, a long-term intake of 2400 to 3000 micrograms of selenium per day would be expected to cause a toxic reaction.
It is unlikely that the diet could provide such a high level of selenium. In fact, there is only one recorded instance of selenium toxicity caused by food in the U.S. It dates back about 50 years and occurred among people living in an area of the country where the soil was unusually rich in this mineral. Only exposure at work or taking supplements would possibly lead to suffering an overdose.
The American experts had this to say in 1977: "There is no justification at this time for the use of selenium supplements by the general population. Should selenium supplements eventually be considered desirable for those persons living in low-selenium areas, or for those consuming vegetarian diets, a daily supplement of 50 to 100 micrograms could probably be taken safely." (Emphasis added.)
The Committee on Diet, Nutrition, and Cancer in the USA said in 1982, "Increasing the selenium intake to more than 200 micrograms a day ... by the use of supplements has not shown to confer health benefits exceeding those derived from consumption of a balanced diet."
3. Sources
It is not easy to list the selenium content of common foods. The main sources in the British diet are meat, fish and cereal products.
The selenium content in plants can vary according to the amount of the mineral found in the soil. The amount in meat, for instance, can vary. It depends partly on the amount of the mineral in the animals' diets. In any case, the average selenium intake is 150 micrograms a day.
Good sources of selenium are:
Meat and seafood are the richest source of this mineral.
Fruit and most vegetables contain little selenium. The selenium content of dairy products and eggs varies.
Iron Can Help
The recommended daily intake of iron is 10 milligrams a day for men and 12 milligrams a day for women. In the context of cancer prevention an adequate intake of iron can prevent a condition called Plummer Vinson syndrome, which has been linked to increased risk of developing stomach cancer and cancer of oesophagus.
Probing these findings, scientists have found that iron deficiency allows bacteria to grow in the stomach. It is possible that these bacteria turn nitrites into the cancer-causing substances called nitrosamines.
But, as is the case with selenium, there is still not much evidence to go on. It certainly makes sense, though, to eat iron-rich foods unless your doctor has advised against it. Some people, though not many, have a disorder that causes them to retain too much iron.
The Best Sources Of Iron
If you are concerned about your iron intake, consider choosing some of these:
The table will help you to choose the best sources.
Sources of Iron - Iron content, milligrams per 100 grams edible portion
Liver, lamb's ............ 7.5
Kidney, pig's ........... 6.4
Bread, whole meal ... 2.7
Beef, average .......... 2.9
Watercress ............. 1.6
Cabbage ................ 0.6
Milk, whole ............ 0.1Cornflakes, fortified ... 6.7
Apricots, dried .......... 4.1
Eggs ......................... 2.0
Bread, white ............. 1.6
Chicken .................... 0.7
Fish, white ................ 0.5
Potatoes ................... 0.4Source: Manual of Nutrition, Ministry of Agriculture, Fisheries and Food, 1985.
Liver, especially, pork liver, contains large amounts of iron. But it is also rich in cholesterol. Too many of us eat too much of cholesterol-containing foods. Egg yolk has a moderate iron content; it, too, is high in cholesterol. About a fifth of the iron we receive is derived from meat.
The iron in flesh foods, called haem iron, is best absorbed by the body. Yet studies have found no more iron-deficiency anaemia among vegetarians than among meat-eaters.
One possible explanation is vitamin C. It enhances absorption of the iron in foods. Vegetarians often consume more vitamin C than meat-eaters. The vitamin C may compensate for the absence of meat in their diets.
A Look At Lead
We are not sure whether lead plays any role in the cancer process. Only a few studies have been done, mostly in animals, and these suggest that large amounts of lead might increase the risk of kidney cancer. But this form of cancer is not very common. Lead does pose a threat to health, but those that are most susceptible are infants, children and pregnant women.
In the United States between 55 and 85 per cent of lead intake comes from food. The lead in canned food can actually seep into the contents and acidic foods packed in cans made with lead are the most likely to absorb this mineral. Fruit and fruit juices, including tomato products, fall into this category. If these foods are stored in the can after opening, the lead content can increase five fold in less than a week. It is therefore wiser to transfer the food, once you have opened a can, to a glass or plastic container. Of course, the threat is from cans which have been soldered with lead, not from unleaded cans. Though research has yet to find that lead or other minerals play a major role in cancer prevention, the story of nutrition and cancer is not yet over. We have looked at vitamins, minerals, fibre, and cancer inhibitors. But there's more to come. The next chapter examines the dietary changes that may offer the biggest dividends of all.
It is a shame that so many people believe that eating less fat means eating food with less flavour. You probably know that eating less fat is the most important step in reducing your calorie intake.
Secondly, eating less saturated fat is the key to preventing heart disease through diet. It is also the best thing you can do to beat the odds of developing cancer.
What makes the case for eating less fat so convincing? Many nations have very low rates of breast, colon, and prostate cancer. If the people of some nations can grow old with little chance of getting these cancers, it is obvious that they can be prevented.
Research spanning forty countries makes clear that these three forms of cancer are rare where diets are low in fat. So are cancers of the ovary and uterus. Scientists have also found that as people give up low-fat diets, they increase their risk of these forms of cancer. Migrants from Japan, for instance, who traditionally ate diets very low in fat, began to lose their low risk after living in the United States.
How Low-Fat Diets Protect Us
Apparently, fat in the diet can affect a woman's hormone levels. These hormone levels, in turn, seem to influence the development of breast cancer. Current theory holds that when little fat is eaten, the hormone pattern is affected in a way that gives breast cancer much less chance of growing. Similarly, fat in the diet probably affects men's hormone levels. Again, when the diet is low in fat, the hormone pattern is unfavourable to the growth of prostate cancer.
And when we watch our fat intake, conditions in the digestive tract discourage the growth of colon cancer. The reason? To digest fat, the body produces substances called bile acids. The less fat you eat, the fewer bile acids you have. Scientists think that the bile acids - or at least some of them - encourage the growth of colon cancer.
How Fat Is Measured
There are several ways to measure the fat in your diet. Nutritionists feel that the most useful is the per cent of calories method.
Fat is one of the few substances in food that provides calories. Apart from fat, the only other food elements that provide calories for energy are:
The calculation of percentage of calories derived from fat indicates the proportion of the day's calories that fat is providing. If fat provides 20 per cent of the calories in your diet, the remaining 80 per cent comes from protein and carbohydrates and, possibly, from alcohol.
In the average British diet, fat provides a whopping 38 per cent of calories. Needless to say, that is too much. Though this average fat intake is too high, few health professionals advocate going to the opposite extreme. The NACNE experts recommend lowering fat intake so that it provides no more than 30 per cent of the day's calories.
Only Four Basic Guidelines
You can meet the 30 per cent fat guideline by following only a few ground rules based on emphasizing:
An Alternative: The Gram-Counting Method
If you have long been a calorie-counter, you may prefer a different approach to watching your fat intake. This involves counting the grams of fat in your food. You do not have to count every gram every day. I suggest doing it for a week or two to get an idea of the foods that will help you cut your fat intake.
To use the gram-counting method of watching your fat intake, you need a rough idea of your ideal calorie intake. Once you know that, you can easily figure out how many grams of fat to allow yourself each day.
To save you the arithmetic, here is a guide. If for example, you need only 1000 calories per day, eating 33 grams of fat per day will keep your fat intake at the recommended level of 30 per cent of calories.
Here is the maximum recommended fat intake for other common calorie requirements:
The table will give you an indication of the amount of fat in foods. This has been calculated on the "bought", not the cooked product.
Fat In Foods - Average fat content, grams per 100 grams edible portion
Milk, whole ................. 3.9
Milk, semi-skimmed .... 1.7
Milk, skimmed ............ 0.1
Milk, dried skimmed ... 0.6
Margarine ................. 81.0
Low-fat spread ......... 40.7
Vegetable oils ........... 99.9
Lard and dripping ..... 99.1
Potatoes ..................... 0.2
Chips, fried ............... 10.2
Chips, oven baked ..... 4.2
Peanuts, roasted ....... 49.0
Bread, white ............... 1.7
Bread, whole meal ...... 2.5
Porridge oats .............. 9.2
Ice cream ................... 8.2
Mackerel .................. 22.9Cream, double ............... 48.2
Cream, single ................. 19.3
Yoghurt, natural low-fat ... 0.8
Butter ............................ 82.2
Cheese, cheddar ............ 33.5
Cheese, Edam ............... 22.9
Cheese, cottage ............... 4.0
Eggs .............................. 10.9
Beef, average ................. 27.4
Lamb, average ............... 25.6
Pork, average ................ 25.5
Bacon, streaky .............. 37.3
Sausages, pork .............. 32.1
Chicken ......................... 12.8
Turkey ............................. 6.0
Fish, white filleted ............. 0.9
Tuna, canned in oil .......... 22.0Source: Manual of Nutrition, Ministry of Agriculture, Fisheries and Food, 1985.
Getting The Best Out Of Dairy Products
One way of reducing your fat intake is to use skim milk and low-fat milk products instead of the ordinary milk and cheese. These provide reasonable levels of fat and calories, but also calcium, protein and certain B vitamins. The best items on your shopping list are skim milk, low-fat yoghurt, and low-fat cottage cheese, though regular cottage cheese is also lower in fat than hard cheese. And, of course, you should change from high-fat to low-fat dairy products gradually. Changes made overnight are not likely to become lifelong habits. Check with the table for a guide to fat content. Here are some suggestions on changing to low-fat milks:
You can save money by making your own "evaporated skim milk." Start with nonfat dry milk and add only half as much water as needed to make skim milk.
Cottage cheese is also a useful ally:
Yoghurt, by the way, substitutes well for buttermilk while baking.
Most hard cheeses are high in fat. But cheese merchants are giving us some lower-fat choices these days. Sodium-watchers cannot use the low-fat sliced cheeses; like most processed cheeses, these contain large amounts of sodium.
Heavy drinkers of coffee and tea need to think about the milk they use. If skim or low-fat milk is used, there is no problem. But cream, or non-dairy whiteners can quickly raise your fat intake.
Use these sparingly; better still, pick a low-fat replacement.
Trimming The Meat
Foods in the meat group are a major source of fat in most diets. But contrary to popular belief, you can eat less fat without drastically cutting your meat intake. Three guidelines are very important:
There is some fat neatly hidden within the muscle of red meat. It is called marbled fat. But most of the fat is around the outside of the meat and in large, visible chunks within the meat. In other words, much of the fat in meat can be seen and cut away. This can reduce the fat and calorie content dramatically.
The fat content of a specific cut of meat can vary from one piece to another. As far as beef is concerned, sirloin, rump, and stewing steak have generally less fat, with sirloin containing, on average, the least. Other cuts of beef, like rib roasts and porterhouse have a reputation for being fatty.
Veal is usually very lean, except for the veal breast. For the meat-lover willing to pay the price, veal is the perfect beef replacement. When buying lamb, choose the leg or loin cuts. These are the leanest. The leanest cut of pork is loin chops.
Processed Meats
The greatest amount of processed and cured meat is derived from pork:
The fat content of these foods is high. And they can also have other drawbacks: a high salt content and the additive sodium nitrite.
You do have a choice. Read the labels or packets and you will be able to see the fat content. This we will also discuss later in the chapter. Some firms, for example are producing sausages with half the fat content of other sausages in their range.
Try to use other fillings for sandwiches: lean roast beef, sliced chicken or tuna salad. Not as good, but preferable to high-fat fillings, are processed poultry products such as turkey breast.
Often these items are low in fat but have a generous sprinkling of salt. Check the label to be sure of the fat content. A fat content of 3 to 5 grams per serving is low; above 10 grams per serving is high.
If you find bacon irresistible, try to limit your bacon to two slices; when you eat only small amounts, the fat content is not too unreasonable.
But do consider some alternatives to bacon and sausages. Try cooked potatoes that have been fried in only a small amount of oil. Better yet, fry them with no oil - use a non-stick cooking spray instead.
You can also oven-fry potatoes. Slice cooled, cooked potatoes; season them with 1 or more spices (garlic, onion and a mild chilli powder are good). Place on a baking sheet that has been treated with non-stick cooking spray, and bake at 180°C (350°F) until both sides are nicely browned. Turn once during cooking.
About Fish And Fowl
In general, fish and poultry are lower in fat than red meat. They are almost always lower in saturated fat as well. That is why heart experts have been advising us to eat more chicken and fish. You should keep these few points in mind:
Fish Gets First Prize
Fish is the real winner when it comes to fat. Most types have very little fat. Some of the lowest-fat fish are:
Even many shellfish contain little fat - despite their reputation for outstanding flavour. This is more evidence that fat and flavour don't always go hand in hand.
Among the low-fat shellfish are such favourites as clams, oyster, crab, lobster, and scallops. Prawns are also low in fat, but they have a higher count of cholesterol than other shellfish. The role of cholesterol in heart disease is well established. It is still too soon to say whether it plays a role in cancer.
A few fish do bear the label of fatty. But this means fatty when compared to other fish, rather than when compared to other foods.
The fattier fish include the following:
These fish have about as much fat as the average cut of red meat.
There is one more category of fish: the canned ones that are often the most reasonably priced. When packed in water, the fat content of tuna is low.
Canned mackerel, herring, and sardines have more fat than tuna or pink salmon. And the oil that is often added makes the fat content higher still. For example, 100 grams of sardines canned in oil has roughly 26 grams of fat - the same in tomato sauce has only 8 grams of fat. Pilchards in tomato sauce contain 5 grams of fat. But take heart, if you drain the oil from the sardines the fat comes down to half- about 13 grams. So be canny about canned fish. Cut down on the fattier varieties. Or try to find brands that don't contain added oil.
Cooking Tips
Fat matters not only to nutritionists but also to cooks. The fat content of meat, poultry, and fish affects the way it cooks. You need to find the cooking methods that work best with the leanest meats, poultry, and fish.
Here are some suggestions on how to get the best results in flavour:
1. Lean Meat
Some people also like using a slow cooker or crock-pot, but I prefer a clay pot for cooking meats. The results are surprisingly good.
2. Chicken
Frying chicken adds to its fat content, but you could pan-fry the meat in a small amount of oil. This adds less fat than deep-fat frying.
3. Fish
Steaming, baking, and poaching are the best of the traditional methods for cooking fish. A microwave oven is equally good, and the results are excellent. Grilling is another method, but it is probably best not to grill fish all of the time for reasons that will be discussed later.
A low-fat fish can quickly become a high-fat dish if topped with a cream-based sauce or lots of butter. Replace some of the fat often added to fish during cooking with wines. When preparing a white sauce, use thin sauces; these require less fat. Replace whole milk or cream with skim or low-fat milk.
Like chicken, fish can be oven-fried. Coat it with a seasoned mixture of cornflake crumbs or flour. You can vary the spices and herbs to make the coating, creating dozens of different dishes. Dip the fish in yoghurt or milk first so that the coating mixture will adhere. If frying fish is a must, sauté it in a pan using only a small amount of margarine, butter, or oil.
You can lower the fat content of tuna and salmon salads by following these suggestions:
High-Cholesterol Foods
Some kinds of meat, poultry, and fish are fairly low in fat, but high in cholesterol. Fat and cholesterol are not the same thing. When it comes to heart disease, however, both saturated fat and cholesterol play a role.
Whether cholesterol in food also plays a role in causing cancer is not known. There is some evidence that a low-cholesterol diet will help to prevent cancer. But the amount of evidence is too small for making judgment.
The best course of action is to keep cholesterol intake, as well as fat intake, at a moderate level. It will help your heart and possibly help to prevent other diseases, too.
Three types of food are notably high in cholesterol:
Offal contains, by far, the highest cholesterol. Prawns are only moderately high by comparison. Offal is not very popular, but you should know these facts:
A prawn cocktail carries only a moderate cholesterol count. It is when prawns are eaten in larger amounts - by the cupful - that the cholesterol adds up.
How Many Eggs?
In most diets, eggs supply far more cholesterol than organ meats or shrimp. A good rule of thumb is to limit egg intake to three or four a week. This is especially important for people who have high blood cholesterol levels or other risk factors for heart disease: high blood pressure, smoking, diabetes, or obesity.
One easy approach is to use the egg allowance for the usual egg dishes such as scrambled and fried eggs. Then find replacements for the eggs used in baking, and other multi-ingredient recipes.
One of the following will often successfully replace an egg used in cooking:
Alternatives To Meat: The Question Of Protein
One of the greatest myths about nutrition is the notion that only meat can supply the protein that we need for good health. There is not, and there has never been, any scientific evidence that this is so.
Consider these facts:
Few people realize that beans, lentils, and nuts have protein that rivals that of meat, poultry, and fish. The fat content, with a few exceptions, is low. That is why we should use them to replace some of the fatty meats in our diets. Nuts and peanut butter are high in fat, while soyabeans and tofu have a moderate level of fat.
Because nuts and nut butters contain mostly unsaturated fat, they should be used to replace some the foods high in saturated fat.
The Oversold Notion Of "Protein Quality"
The quality of these plant proteins as compared to animal proteins is the second part of the protein myth.
Though animal proteins do have higher-quality protein than most vegetable foods, most adults simply do not need the extra protein that meat provides.
Vegetarians prove this point beautifully. Most vegetarians eat dairy products and eggs, which provide more than enough protein.
But even adult vegetarians who eat no animal products at all have been found to eat about twice the minimum requirement of each protein that humans need.
Some people do have to take special care if their diet contains no animal protein. In this category are:
Vegetable protein can meet the needs of people in these situations, but care and planning are required. Grains and legumes should be combined to provide high-quality protein, and soya foods should be eaten regularly.
And as far as fruit and vegetables are concerned, with only three exceptions - olives, avocado and coconut - all are very low in fat.
These three are generally eaten in small amounts so one should keep it that way. But if you eat a whole jar of olives then the fat starts to add up. Sodium watchers though should leave olives on the plate.
The Misunderstood Starches
The most underrated element in our diet is the starches. Foods such as bread, pasta, rice, and cereal deserve high marks. But instead they have been put down as fattening and non-nutritious. There never has been a worse misconception. We should be eating more of these starches. Yet many people avoid them.
Most foods rich in starch have a lot going for them. Foods in this group usually have the following good points:
And they have the most important advantage of all: very little fat. Most forms of bread are low in fat. At the table, try not to overdo the margarine, butter, or cream cheese. It is the fat added to starchy foods, not the foods themselves, that makes them fattening.
If You Have A Sweet Tooth
If you are tired of being told to eat fruit for dessert, do not despair. Of course, fruit is an ideal pudding: low in fat and often rich in certain vitamins. But most people want more variety than fruit can provide. On a low-fat diet, there are other options. You can choose, if you are particularly addicted to sweet things, the puddings and pies that have lower contents of fat.
If you look at the table below you will see some startling results. Very often the canned puddings that you think of as being rich and sweet are in fact lower in both fat and sugar than homemade puddings. And of course you have a choice in pies. You can choose one that has both a pastry top and bottom, or go for either a flan or a pie with only a pastry top. The table also gives you a calorie count as well, so you have a good idea of what the best choices are for reasonably low-fat, low-calorie puddings.
Evaluating Puddings
Source: McCance and Widdowson's The Composition of Foods
If you are good at making your own puddings, cakes and biscuits, you could choose the more sensible ones. However, if you don't have that particular talent then use the guidelines to keep your fat intake at a moderate level.
Different Types Of Fat
A hundred years ago, there were generally only two types of fat available: butter and lard. Today, there is a much wider range for the consumer. They include:
While all are high in fat, they contain different kinds of fat. Some of the fat in food is saturated, while other fats are mono-unsaturated or polyunsaturated.
We know that saturated fat raises the blood cholesterol level which, in turn, is one of the three major factors that determines your risk of heart disease. Polyunsaturated fats help to lower blood cholesterol. But they are not as efficient at lowering blood cholesterol as saturated fats are at raising it. So, as far as preventing heart disease is concerned, it is better to eat less saturated fat.
However, when it comes to cancer, all fats are on equal footing. Scientists believe that eating less of any type of fat would help prevent cancer of the breast, colon, and prostate glands. They have not yet concluded that any one type of fat has more effect on cancer than another. This makes the message about fat and cancer much simpler than advice on preventing heart disease. You need to apply three very simple guidelines to your diet:
Saturated Or Unsaturated?
For those interested in preventing both heart disease and cancer, I have outlined the different kinds of food and the predominant fat that they contain, whether saturated or unsaturated. Remember also that food labels may help.
1. Saturated Fat
All foods contain some type of each type of fat, but nutritionists generally classify it by the kind of fat that predominates. Therefore, the following can be thought to have saturated fats:
Industrial shortenings are those used in processed foods. They are generally present in a wide range of ready-made products.
2. Polyunsaturated Fats
You have a wide range of choice:
3. Mono-unsaturated Fats
Olive oil, peanut oil, many margarines, and some industrial shortenings are mono-unsaturated. The mono-unsaturated fats have little or no effect on the blood cholesterol level.
The fat in chicken and fish is less saturated than the fat in red meats. This is why heart experts recommend eating more fish and poultry.
Fat And Calories
The best way to diet is to eat less fat. The reason is simple: fat has more calories than anything else in food.
Little wonder that obesity is common in nations that have high-fat diets. (If you are wondering what a gram of fat looks like, it measures a little less than a quarter of a teaspoon.)
We can only do ourselves good by eating less fat. We have known for decades that the body needs only about 10 per cent of its calories to be derived from fat. The British diet averages four times that.
Generally, children under a year old should not be fed a low-fat diet unless ordered by a doctor. During the first year of life, many infants need the extra calories that fat provides. In the UK, the National Advisory Committee on Nutrition Education (NACNE) recommended a reduction of the average total fat intake from 38 per cent of calories consumed to 34 per cent. The experts also felt that the intake of saturated fat should come down from 18 per cent to 15 per cent of total calories consumed.
If you follow the recommendations in this chapter, you will almost certainly reduce you calorie intake. It is just another reason, among many, to eat less fat.
Alcohol can cause all kinds of trouble: traffic accidents; family problems; liver disease; nutrient deficiencies and cancer. But the research linking alcohol to cancer doesn't have scientists advocating Prohibition. They advocate a moderate approach. It is excessive drinking that has been linked to cancers of the stomach, colon, and rectum. Research also shows that heavy drinking combined with smoking greatly magnifies the chance of developing cancer of the mouth, throat, and oesophagus.
Any objective discussion about alcohol should cover its role in heart disease as well as in cancer. Research shows that modest drinking reduces a man's chances of having a heart attack. Heart disease, of course, is far more common than the cancers linked to alcohol.
What is a moderate approach? If you are wondering how you can be a "moderate" drinker, here are some guidelines for you, developed by the Health Education Council. A wise approach is based on the "standard" drink formula, which the Council has devised, and also the kind of alcohol and how often you drink. The Council recommends, if you have to drink, that it would be best to consume two or three "standard" drinks, two or three times a week for women.
For men it is best to keep to two or three pints (or their equivalent) two to three times a week.
One Standard Drink Is Equal To:
Source: Health Education Council
Of course, there are many ways of cutting down on the amount of alcohol you drink. If you are pouring a drink at home, the measures are generally much more generous than those at a pub. So look carefully at how much you pour into your glass and you might find the equivalent of two, three or even four standard drinks.
Using the tables below you will realize that a half pint of beer is equivalent to a single whisky, or a glass of wine. Extra strong lagers contain almost as three times as much alcohol as ordinary beer. So if you are mixing yourself a drink, you can always put in less alcohol and top it up with a larger amount of non-alcoholic mixer and you could always choose the beers, wines, and mixed drinks that have a lower alcohol content.
How Many "Standard Drinks" In Your Drink?
These figures are approximate. Source: Health Education Council.
The Heart's Desire?
Research has shown links between moderate alcohol consumption and a lower risk of heart disease. Most heart attacks result from fatty deposits that clog and harden the arteries that supply the heart with blood. The most common type of cholesterol in the blood, LDL-cholesterol, promotes the clogging process.
Foods rich in saturated fat and cholesterol raise the amount of LDL-cholesterol in the blood. This high cholesterol level, in turn, encourages the clogging of the arteries.
As far as we know, alcohol does not affect the level of LDL-cholesterol. What it does seem to affect is the amount of another component of blood. This component is called HDL-cholesterol, and it is linked to lower risk of heart disease. You might say that its effects are the opposite of those of LDL-cholesterol. Rather than promote the clogging process, it apparently helps to slow it down.
Research shows that men who regularly drink small amounts of alcohol have higher levels of HDL-cholesterol than do non-drinkers. Whether this is also true for women is unknown. Few heart studies have been done with women. Other factors linked to a healthy level of HDL-cholesterol are exercise, normal weight, and nonsmoking.
Drinking a great deal on the weekend but almost none during the week does not qualify as moderate drinking. And heavy drinkers do not do well at all when it comes to heart disease. They have a greater than average risk.
Although the number of studies show similar results regarding moderate drinking and heart disease, we have yet to learn how drinking affects total life expectancy. We cannot interpret the research on heart disease to mean that moderate drinkers live longer than non drinkers. We do not know that this is so. But more Americans, for example, die of heart attacks than cancers (or other diseases) linked to alcohol. For this reason, I am not ready to say that moderate drinkers should not drink at all.
Remember The Calories
When you do enjoy an alcoholic beverage, remember that it is not a diet drink. The calories in these drinks add up - quickly. Here are a few figures that speak for themselves:
A rough guide to calories in popular mixed drinks shows this:
I can often be heard saying that eating less food is the best way to lose weight. But these figures make clear that drinking less alcohol comes in a close second.
Preservatives have been a familiar element in the kitchen for a long time. Salt and sugar were commonly used when preserving was done at home. Today this has moved to the food factory where the number of additives has increased enormously. While many are innocuous, the manufacturing process may demand high levels of others such as salt which, in excess, can have harmful effects.
In the USA, the Committee on Diet, Nutrition and Cancer pointed out in 1982 that there were almost 3000 substances intentionally added to processed foods and that another 1200 chemicals, were classified "indirect additives." Very few of these additives have been tested for long enough to assess their cancer-causing potential. In the UK, the Health Education Council has estimated that the daily consumption of additives in the average British diet is equal to ten aspirin sized pills.
Nitrites
Processed and cured foods figure prominently in the average British diet. Nitrites are used in products such as bacon, and ham. They have been implicated in cancer in animals, and as a factor in causing cancer of the stomach and the oesophagus in humans. The human stomach may convert nitrates and nitrites to the family of cancer-causing substances known as N-nitroso compounds, or nitrosamines.
Nitrosamines can cause cancer in different animals; some are so powerful that even tiny amounts can cause cancer in test animals.
Potassium nitrite (E249), sodium nitrite (E250), sodium nitrate (E251) and potassium nitrate (E252) are used in cured meats because they offer protection against bacteria which could cause severe food poisoning such as the botulism outbreak in the UK some years ago.
Apart from their value in preventing contamination by bacteria these additives act as a colour fixative and flavouring agent.
The Committee on Diet, Nutrition and Cancer in the USA advised people to eat very little of salt-cured and salt-pickled foods. Some of them are:
Of course, it is going to be much easier for people now to check whether the foods have been salt-cured - all you need to do is look at the label and look for the number E250.
Healthy Substitutes
There are many ways in which you can reduce your consumption of salt-cured foods. Here are some tips.
1. Sandwiches
Obviously some of the most common salt-cured foods often appear between slices of bread or in rolls: hot dogs, salami, liver sausage, and other luncheon meat. There are tasty alternatives: lean roast beef, sliced chicken or turkey, tuna, salmon or peanut butter. If you like pickled vegetables or relishes, try to substitute the fresh version instead.
2. Spices
If you feel that your sandwich or roll doesn't have the flavour that you associate with the cured meats, use a sauce or herb to spice it up. Oregano, sage, and fennel can be flavoursome ingredients in a sandwich.
3. "Take with Vitamin C"
If you still can't resist salt-cured foods or are addicted to bacon, for example, be sure to eat a food rich in vitamin C at the same time. As I've already told you, this vitamin can help block action that turns nitrites into cancer-causing nitrosamines. So, try these alternatives:
You may notice that many cured meats list vitamin C as an ingredient. Manufacturers use it to stabilize the colour and flavour of cured meats. It may serve health at the same time by helping to block formation of nitrosamines.
However, the amount of vitamin C added to processed meats is fairly small and we do not know whether this is enough to provide strong protection against nitrosamines.
For this reason, it is probably wise to eat fruit or vegetables rich in vitamin C when having cured meats.
Rating Cured Foods
We have a wide selection of cured meats. Ham, bacon, gammon, tongue, brisket and pork shoulder would be the recognisable ones. But there are other kinds of cured meats. Technically termed compound meats, some of these are: liver sausage, luncheon meats, pates and corned beef.
It may be that you are so fond of cured food that you cannot do without it. In that case look at the labels and try to choose the product that has the lowest fat content.
For example 100 grams (a little over 3 ounces) of lean gammon rashers, grilled, contain two grams of saturated fat whereas streaky bacon rashers, grilled, have 14 grams of saturated fat. In fact, when you add up the total fat content, the lean gammon rasher comes out with about five grams of fat and the streaky bacon rasher with 33 grams. Grilled pork sausages only give you 23 grams of fat.
So be choosy about cured food if you cannot give it up.
The Rainbow Of Artificial Colours
Just as you can be selective about cured meat, be inquisitive about additives. Many are used to colour foods and some of them are natural, such as chlorophyll, the green pigment found in plants. By and large artificial colours are probably not a major cause of cancer. Yet it does make sense to avoid them whenever possible since their safety has not been firmly established. Some people have sensitivity reactions to certain colourings also.
While some colours can be natural, such as the orange from the spice turmeric, similar colours are derived synthetically. The orange-yellow dye tartrazine (E102), used in soft drinks, biscuits, cakes, puddings and desserts, meat products and sauces, is a synthetic dye. People who are sensitive to aspirin and those who suffer from asthma may experience a reaction from the synthetic coal-tar dyes (which include the group called azo dyes).
A large number of convenience foods and products use synthetic coal-tar dyes, which have been linked to cancer in animals. The family of these dyes and azo dyes now used in foods includes:
The kinds of products they would appear in would be:
A general principle would be to minimize use of products with synthetic colouring. However, these colourings cannot be considered a major cancer risk factor.
The Sweeteners Story
Low-calorie sweeteners have been around for decades and no doubt they are here to stay. Those in use today are:
Some of these may be safer than others. The safety of saccharin has been heavily debated in recent years. There is little question that it can cause cancer in laboratory animals when fed in large doses.
Whether these findings are important to humans is a matter of opinion among scientists. Regular use of saccharin may pose a significant risk. But the risk is probably not great; some studies have not found higher rates of cancer among heavy users of saccharin.
Aspartame, saccharin's new competitor, is probably a safer choice.
It is of protein origin and is likely to be found in soft drinks, confectionery, ice cream and low-calorie desserts.
During digestion, aspartame breaks down into two substances that our bodies encounter every day in ordinary protein foods.
Though there have been reports that aspartame can cause cancer in animals, the Food and Drug Administration in the USA has concluded that aspartame is safe and does not cause cancer.
Foods sweetened with aspartame will no doubt become more and more common in future years. Aspartame can replace sugar in coffee or tea and be used to sweeten fruit and other foods. It cannot replace sugar used in baking.
Another sweetener, mannitol, provides more calories than aspartame or saccharine, but it has only half as many calories as sugar. It is used in a few sugarless products, including chewing gum. On the basis of research now available, there seems little doubt about its safety.
A related substance, sorbitol, is also used in dietetic foods. It can occasionally cause intestinal pain and diarrhoea in people who eat large amounts of it. Otherwise, however, sorbitol is considered quite safe. It occurs naturally in fruit and berries.
Some Additives Are Nature's Own
Opponents of food additives sometimes give the chemists a little too much credit. They accuse food technologists of inventing thousands of foreign substances to add to our food. Quite often though, as I have said earlier, the chemists have only copied Mother Nature's own designs. Many of the additives in use are substances that occur naturally in food.
A natural substance becomes an additive whenever it is used in a food in which it is not naturally found. Vitamin C is present in oranges and orange juice, but when it is used in a meat product, it becomes an additive.
Natural Anti-Cancer Additives
Another common additive not only occurs naturally but may have anti-cancer potential - carotene. Margarine manufacturers, for example, use carotene for several reasons. One is to give it a yellow colour, but it is also added so that the margarine can provide as much vitamin A value as butter. Ironically, the form of vitamin A in butter, called retinol, may lack the anti-cancer potential of carotene - so the 'natural' butter may lack the anti-cancer ingredient found in 'unnatural' margarine.
Other additives that may have anti-cancer value are vitamins C and E. Vitamin C is often added to food to prevent rancidity and to stabilize the colour. We have already looked in detail at its anti-cancer activity.
Vitamin E is used as an additive less frequently. When used, it, too, helps to prevent rancidity.
In theory, vitamin E might help prevent cancer because it is an antioxidant. Some chemicals seem to cause cancer only when oxidized.
By preventing oxidation vitamin E might have value. But, we still need research to test the value of this vitamin.
Some elements which occur naturally in certain foods have properties that are needed in other products. These are also classed as additives. They are:
There are other natural substances such as the different kinds of gums added to foods. They are generally used to thicken and stabilise a wide variety of food. The most common of these are:
One gum, tragacanth, has caused a few cases of allergy.
The "Uncertain" List In The USA
Scientists who reviewed food additive safety for the Food and Drug Administration in the USA said that a handful of additives appear safe as now used but added that unanswered questions remain. Only more testing, of course, will give the answers.
When other aspects of diet and nutrition, such as reducing fat intake, are so important it makes little sense to pay undue attention to the few additives that fell into this category. But you may want to be aware of their opinion:
Strangely enough, scientists believe that BHA and BHT might help prevent cancer. Like vitamins C and E, these are antioxidants, considered to have anti-cancer value by some cancer scientists. No doubt, the pros and cons of BHA and BHT will be much debated during the next few years.
Popular, Natural, But Unhealthy
There are, of course two household favourites, that are the most commonly used additives, and are not particularly healthy if consumed in excess. These are sugar and salt. Sugar contributes to tooth decay. The NACNE report says that the average consumption of sugar is 38 kg a year and that this should be reduced by roughly half, cutting down as much as possible on sugar, confectionery, soft drinks, and sweet snacks.
Salt is implicated for its role in high blood pressure, a risk factor for heart disease. About a third of all deaths under the age of 65 in England and Wales are due to high blood pressure and related causes. The average UK intake of 12 grams of salt a day is far in excess of the needs of even the most active of individuals.
The NACNE experts say that cutting down to a half or a quarter would not pose any danger to health but that such "a drastic reduction would necessitate major changes in food manufacturing and marketing." It would be realistic, they say, to reduce daily salt intake by one gram as a starting point.
In short, a decade of debate has made it clear that many food additives do appear to be safe. Some look like trouble-makers, and others need better testing. But these are the exception rather than the rule.
Though most additives probably do not cause cancer, it is foolish to assume that none of them do. Each must be studied individually.
Insisting that all food additives are safe makes no more sense than saying, "Everything causes cancer"!
11 - Naturally Occurring Toxins
We think of nature as a life-giving force. But it also has another, more sombre face, such as the infectious diseases. Among the cancer hazards imposed by nature are those that are present in food, but they seem to play only a small role in the cancer process. Among the hazards that may occur naturally are:
Studying the components of common foods is an enormous task, but there has been detailed research on some aspects, including some things we almost take for granted.
The Household Favourites
The link between coffee and cancer has been the subject of more than a dozen studies. The results can be described in one word: conflicting. In a nutshell, here is what American experts had to say:
Needless to say, it is not easy to draw conclusions from these results. It is obviously best to emphasize those findings backed by solid research. In other words, it is most important to ensure a good intake of fruit and vegetables rich in vitamins A and C and to limit your fat intake.
I am not convinced, however, that heavy coffee drinking is without risk. My own advice to coffee-lovers is this: keep your coffee-drinking in the range of three to five cups a day (or less).
Incidentally, those who have confirmed heart trouble would do best to avoid coffee. It has been linked to abnormal heart rhythms and to a disorder called VPB (ventricular premature beats).
1. Different Types of Coffee
Cancer researchers cannot say whether instant coffee is preferable to brewed coffee, or vice versa. Scientists also need more time to determine whether decaffeinated coffee poses less (or more) risk than regular coffee.
There has been some concern about the safety of the chemical used to remove the caffeine from coffee. Traces of the chemical can remain in the final product.
Trichloroethylene was the chemical used, but now some companies use a chemical-free process to remove caffeine, while others use a methylene chloride instead. The safety of this chemical has not been shown to the satisfaction of all. When compared to other aspects of nutrition and cancer, however, this is a very minor issue.
Caffeine, of course, causes 'coffee nerves' in some of us. The caffeine content of coffee varies, depending on brewing conditions and the type of coffee used. Generally speaking, instant coffee has about half the caffeine content of fresh brewed coffee.
Caffeine is also found in chocolate, cocoa and some soft drinks.
2. Memo to Tea-Drinkers
Tea long has been in coffee's shadow. But cancer scientists have been every bit as interested in evaluating its safety.
So far studies have concentrated on individual components of tea, the best - studied components being caffeine and tannins. Both of these are also found in coffee.
Tannins actually occur in a wide range of plants. Food manufacturers often use small amounts of a tannin called tannic acid which can be added to a variety of products, including butter, sweets and dessert mixes. Breweries and distilleries add tannic acid to beer and other alcoholic beverages.
3. A Sensible Approach
While caffeine should not be recognized as absolutely safe, mostly because of its effects on the nervous system, it is doubtful whether caffeine poses a cancer hazard. It can cause mutations in bacteria, but there is little evidence for judging the ability of caffeine to cause cancer in animals or man. Tannins have not shown the ability to cause mutations in bacteria, and scientists consider this a hopeful sign that tannins do not cause cancer. But some experts do recommend adding milk to tea as this is believed to bind up the tannin and prevent it from having a harmful effect.
Natural Nitrites And Nitrates
We have already looked at the question of nitrites in cured meats and the recommendation to eat few salt-cured and salt-pickled foods. Nitrites are an important building block for cancer-causing nitrosamines. When nitrites are used in curing meat, a related substance, nitrate can also be used. Nitrates pose a problem only if converted to nitrites. This transformation can take place in the mouth or the digestive tract. On the other hand, vegetables and fruit contain nitrates and in fact the single largest source is vegetables. Nitrates also occur in juice and water, but it is clearly felt that the good points of fruit and vegetables - their vitamin A and C content - far outweigh the potential hazard of the nitrate.
The Aflatoxin Story
The second type of naturally-occurring toxins are unwanted substances that sometimes grow on food. Scientists have long known that bacteria and moulds that develop on food can cause infections and allergies. But it is only recently that scientists realized that some kinds of mould can produce cancer-causing compounds. One such mould produces the well- publicized cancer agent, aflatoxin.
Some aflatoxins show powerful cancer-causing activity in animals. Whether humans are as susceptible unknown. But impressive studies in Africa and Southeast Asia have shown a strong link between aflatoxins in food and rates of liver cancer.
Aflatoxins are produced by the mould that generally affects food that has been stored, as for example, peanuts (groundnuts) in places such as West Africa. Aflatoxin came to public notice in England when there was an outbreak of aflatoxin poisoning among turkeys who had eaten mouldy peanuts.
Aflatoxins can find their way into milk, eggs and meat if the animal feed was contaminated with the substance, but strict regulations attempt to prevent this.
As a general rule, try not eat foods that have gone mouldy - you can always cut away the mouldy part. If you are eating nuts that are in the shell, examine them after opening and throw out those the are mouldy or shrivelled. And do your pets a favour, do not give them any mouldy food, either.
It is simply impossible to avoid all cancer risks, so it makes sense to emphasize the foods that help to prevent the major forms of cancer. Doing so leaves room in our diet for moderate use of foods that sometimes contain aflatoxins.
A Look At Fermented Foods
Bread and yoghurt may seem to have nothing in common with beer and wine, but they do. In one way or another, all of those foods involve the process called fermentation.
Scientists have long known that a compound called ethyl carbamate can cause cancer in laboratory animals. Yeasts that ferment food produce substances that can react to form tiny amounts of ethyl carbamate.
The Committee on Diet, Nutrition, and Cancer in the USA seemed to doubt that the amount of this chemical in fermented foods poses a great threat to our health. Fermented foods provide extremely low levels of this substance - far less than is used to cause cancer in rats, mice, and hamsters.
It looks as though that old tradition of "a loaf of bread, a jug of wine, and thou" will survive.
Like many scientists, I believe that certain foods can help to protect us from developing cancer. On the other hand, it seems to me that some foods may actually invite the cancer process. New research shows that it is not only what we eat but how we cook it that may affect the chances of developing cancer.
It seems that certain methods of cooking food increase the chances of suspect chemicals forming in it. But this is not a doomsday story. The facts do not show that all methods of cooking produce high levels of potentially dangerous substances. It is simply a matter of knowing the best ways to cook food Cooking meat at high temperatures - whether over charcoal or in an oven increases the mutagens in it. Mutagens are substances that can damage genes. Scientists believe that most substances that can do this can also cause cancer.
Cooking meat at high temperatures also causes changes in the protein. Some of the changed proteins appear to be mutagens. For the most part, the mutagenic proteins seem related to the charring of the meat's surface. Therefore, browning meat in a frying pan probably also causes this problem.
A related problem is when meat is surrounded by a great deal of smoke. There is at least one cancer agent in smoke that can lodge on the meat. It is called benzo(a)pyrene.
This chemical forms most easily when meat is cooked over, and close to, a very hot source of heat. It also is more likely to form on fatty meats than on lean meats. Charcoal-grilling of fatty meats is the classic example of a cooking method that causes this problem.
How Important Are These Problems?
Not enough is known about these chemicals induced by grilling to say how important (or unimportant) they are. We may hope that protective substances in food, such as vitamin C, might help counteract the effects of these possibly dangerous compounds.
If these mutagens do play a role in cancer, it is probably in colon cancer. If you eat a diet high in fat and low in whole grains and cabbage family foods, you may be at high risk for colon cancer. You do not have to give up grilled and fried meats - simply eat less of them and cook only until rare or medium rare.
Advice Into Action
Translating these considerations into action can be easy. There are some guidelines to follow, but you don't have to be obsessed by them. Just try and follow them whenever it is practical. Here are the guidelines:
Making The Most Of Meat
As any cook can tell you, some red meats are better suited to these recommendations than others. Here is a review.
For cooking in the oven and roasting, the best choices are large cuts of beef. They are excellent as a roast done either in a traditional or microwave oven. Round, rump, rib, and tenderloin can be cooked this way. The rib cuts, though, are unusually high in fat.
Large cuts of lamb, veal, and pork also roast well. Though the guidelines above suggest cooking meat only to the medium stage pork always should be cooked until well done. Undercooked pork occasionally contains organisms that cause the disease known as trichinosis. Pork chops more than an inch thick can be cooked in the oven with good results. If the supermarket does not offer thick chops, ask the butcher to slice some for you. You may find them tastier than the thin ones! Grilling has long been favoured for steaks and lamb chops, but you might try braising. You may like it.
More Meat Ideas
If you have more than an hour before serving time, you can make easy yet delicious meat casseroles.
Minced lamb, for instance, can be mixed with diced aubergines and tomato puree then cooked in a casserole. Ground beef can be mixed with any number of vegetables and cooked the same way.
These dishes take longer to cook in the oven than a frying pan or under the grill. Nevertheless, it takes only a few minutes to assemble the ingredients and after that is just a matter of letting them cook. You can also reduce the cooking time by using a microwave oven.
Cooking meat slowly, in liquid, is another way to prepare meat without charring it. Diced beef is well suited to stewing, but simmer, don't boil, or use a crockpot.
About Microwaves And Meats
Some cuts of meat can be cooked successfully in microwave ovens but others sometimes cook unevenly. It is best to choose meats that are small and uniformly shaped. Lean meat cooks better than fatty cuts. The following cuts of meat can usually be cooked in a microwave oven with good results:
The beef cuts that are less suited to microwave cooking are sirloin, Tbone, and porterhouse steaks. The latter two are usually high in fat as well.
Chicken Without Charring
Basting a roasting chicken with a good barbecue sauce offers a tasty alternative to charcoal-grilling. Simmering chicken in liquid works best with dark meat. The white meat does not respond as well to moist heat. If you use light and dark meat together, the results will probably be acceptable. You can also oven-fry chicken instead of frying it in oil.
I suspect that discarding the skin after grilling chicken may be another way around the problem. The mutagens created by charring meat probably occur near the surface. Therefore the majority of these substances may form on the skin.
My suspicion remains to be tested, but keep in mind that chicken skin packs more fat and calories than the meat itself. For these reasons alone, it is a good idea to eat only the meat.
The versatile chicken can also be cooked in a microwave oven.
The results are excellent.
Don't Forget Fish
Like chicken, most fish tastes delicious when cooked in a moderate oven. Some people disagree, but it may be because they overcook fish. Most fish takes little time to cook and should be done only until it flakes easily with a fork.
You can also oven-fry fish. Coat with a mixture of seasoned flour or cornflake crumbs. Use your favourite spices and try different combination. Basting with a tangy barbecue sauce is an alternative to charcoal grilling.
Steaming and poaching are other options. Fish also cooks beautifully in microwave ovens. I especially enjoy fish that has been done in a clay pot.
A Reminder
When you grill or fry meat, cook it only to the rare or medium stage. This will reduce the level of mutagens. The exception, of course, is pork. It should always be cooked until well done.
13 - Will Preventing Heart Disease Cause Higher Cancer Rates?
According to Murphy's Law, "If anything can go wrong, it will". There have been hundreds of more specific versions, covering everything from clothes to computers.
If there were a Murphy's Law of Nutrition, it would probably read something like this: "Change your diet to prevent one disease, and you will get another disease instead".
Apologies to Murphy, but the facts do not support this brand of pessimism. Health experts have long believed that as each disease is conquered, overall life expectancy will improve.
Consider coronary heart disease - death rates in the UK are among the highest in the world. This disease alone accounts for two out of every five deaths in the United States each year. Most victims of this disease have one or more of the following conditions: high blood cholesterol, high blood pressure, or the cigarette habit.
Thanks to efforts to reduce blood pressure, blood cholesterol, and cigarette use, deaths from coronary heart disease have fallen by 20 per cent in the United States since 1968.
The pessimist would laugh, saying so many people died of other diseases instead - diseases that are even worse than heart disease.
But the statisticians have a different answer. Their numbers show that when heart disease rates went down, overall life expectancy for Americans went up.
The Facts Are Reassuring!
A few years ago, some heart studies showed that men with the lowest blood cholesterol levels had the higher than expected rates of cancer. Not one study, though, found such a link in women. These reports led to a massive study of this possibility. The National Institute of Health in the United States contacted dozens of heart researchers worldwide to find out if low cholesterol levels were linked to a higher risk of any or all forms of cancer. The conclusion supported my convictions about reducing fat and cholesterol intake.
A Wrap-Up Of The Findings
When the scientists combined their results of seventeen different studies, they found no consistent link between cholesterol levels and cancer - with one that exception I will tell you about shortly.
There was no link between cholesterol levels in women and cancer rates. In men, some studies found lower cholesterol levels among cancer victims. Other studies showed that cancer victims tended to have higher cholesterol levels than healthy people. Nine of seventeen studies showed no link between low cholesterol levels and cancer.
What about those studies that found higher cancer rates among men with low blood cholesterol levels? The scientists talked of the " chicken or egg" question here. Did the low-cholesterol level cause the cancer -or did the cancer cause the low cholesterol level? Some of the scientists proposed that the cancer probably caused the cholesterol levels to fall -something that could have happened years before the cancer was diagnosed. One expert found that cholesterol levels fell when the disease was active - and rose when the cancer went into remission. In other words, his research showed that cancer can dramatically affect the blood cholesterol level.
The Vitamin A Connection
More likely than not, the cancer itself has caused the low cholesterol levels found in studies that link the two conditions but there is another possibility.
Researchers have found a striking link between low cholesterol levels and low levels of vitamin A in the blood. The two seem to go hand in hand.
It is possible, then, that the low cholesterol level is only a sign of what is really wrong: too little vitamin A in the blood.
Whether or not this is the answer, no one can say. But at the conference, one scientist after another expressed doubt that low cholesterol levels cause cancer. I doubt it, too.
The Exception: Colon Cancer
Scientists studying the cancer and cholesterol connection looked first at the total cancer rate. This rate combines all forms of the disease.
Their second look considered each different type of cancer. For all forms of cancer except one, at most two of seventeen studies found any link with low cholesterol levels. This is rather convincing evidence that low cholesterol levels are not linked to most forms of cancer.
The exception was colon cancer. Six studies showed a tendency for male colon cancer victims to have low cholesterol levels. By "low", scientists usually meant levels of 180 milligrams per 100 millilitres of blood or less.
Only about 12 per cent of middle-aged men in the United States have cholesterol levels this low. Nonetheless, that is no reason to ignore these finding. I think that the research is telling us something.
Explaining The Link
Scientists have long known that some people can eat diets loaded with saturated fat and cholesterol yet keep a low blood cholesterol level. These people are the exception rather than the rule. But they can be found.
Ten years ago, nutritionists like myself used to describe these people as "lucky." But it is time to think again.
People do handle the saturated fat and cholesterol that they eat in different ways. These food elements generally raise the blood cholesterol in most people.
There are other possibilities, however. Saturated fat and cholesterol can also be changed into bile acids in the digestive tract. These bile acids can then be excreted from the body. We used to think that this was for the best - anything to keep the cholesterol out of the blood. New knowledge, though, demands that we reconsider this view.
As discussed in the chapter on fats, scientists believe that some of the bile acids encourage colon cancer. These bile acids do not cause the disease directly; rather, they enhance the power of the substances that do cause it.
So it is no mystery why men who have low blood cholesterol levels could have higher rates of colon cancer. They are handling the fat and cholesterol in their diet in a peculiar way that lowers risk of heart disease but increases the chances of colon cancer.
The Solution Is Simple!
The research here does not tell us that we have to pick one or the other - heart disease or colon cancer. In fact, the risk of both can be lowered by the same diet.
When foods rich in complex carbohydrates (vegetables and grains) replace some of the fat and cholesterol in the diet, the chances of both heart disease and colon cancer should fall.
Health statistics from other countries support this recommendation.
In Japan, for instance, the diet of most people is low in fat and rich in complex carbohydrates. The rates of both heart disease and colon cancer are low - much to the envy of health experts.
A Few Words About Salt
The Japanese diet is not without its flaws. The people of Japan consume enormous quantities of salt. The unfortunate result is rampant high blood pressure. The sodium in salt apparently does the damage.
Salt has not been linked to cancer. Cancer research points a finger at salt only when it is part of foods that are cured and pickled.
Other salted foods have no known role in cancer.
But do cut down on salt. The World Health Organization recommends 5 grams a day, the national average in the UK is 12 grams. High blood pressure would occur less frequently if we cut back on salt and foods high in sodium.
Salt-Watching Made Simple
There are two basic rules for cutting back on salt: eat fewer processed foods and go easy in cooking and at the table. Some of the most common processed foods that are high in salt are:
Smoking Hurts, Too
Needless to say, smoking does not enhance anyone's health. On the contrary, it increases the risk of both heart disease and cancer.
Cutting back on cigarettes, or better yet, parting with the habit will reduce the risk of both diseases. Much to their pleasure, researchers have found that ex-smokers can definitely benefit from quitting.
It takes time, of course, for the benefits of quitting to take hold.
But studies show that as the years go by, ex-smokers gradually attain the lower-risk status of those who have never smoked. Who could ask for more?
Some Words About Weight
Your weight may affect your chances of developing both cancer and heart disease. But it is true obesity - not a few extra pounds - that significantly increases one's chances of developing cancer. This is also true for heart disease. Even when weight does play a role in heart disease, however, it is not as strong an influence as the top three risk factors. These three factors, of course, are high blood cholesterol, high blood pressure, and smoking.
A large study conducted by the American Cancer Society found that seriously overweight men had higher than average rates of colon and rectal cancer. The same study showed that seriously overweight women had higher rates of cancer of the breast, gall bladder, cervix, uterus, ovary and endometrium. (The endometrium is the lining of the uterus.)
I hope you have noticed my use of the term "seriously overweight." All too often people think they weigh too much. From the standpoint of good health, though, many such people are at normal weight.
When people weigh about 30 per cent or more above average for their height and age, scientists find a noticeable increase in the chances of getting cancer or heart disease. For those who do not exceed average weight by this much or more, there is often no excess risk of heart disease or cancer.
If Your Weight Is Average
It is hard to make a case for rigorous dieting among people whose weight is just plain average. In fact, the best research I have seen shows that the slimmest among us are not necessarily the healthiest. Recent studies have found that, as a group, people of average weight live longest.
It is important, of course, to understand the perils of serious obesity. But it is also important to be aware that "skinny" is not the only alternative to "fat." There is a middle ground - normal weight.
Passing judgement on a person's weight from a book is difficult.
Your doctor is the best judge of whether you are overweight. If you weigh five or seven kilos above "skinny," chances are that you are not obese. On the contrary, your weight is probably normal.
To Sum Up
Scientists do not want to prevent heart disease by causing other diseases instead. They want prevention of heart disease to result in better health.
The factors that help your heart are normal levels of blood pressure, blood cholesterol, and weight. Being a nonsmoker is also a major plus.
None of these four characteristics has been linked to a higher risk of any form of cancer - except colon cancer.
The exception, again, involves men who typically maintain low levels of blood cholesterol (below 180). These men may have higher than average risk for colon cancer but, say experts, "the magnitude of this risk is generally modest."
In fact, some of the same measures that prevent heart disease seem likely to lessen the chances of some forms of cancer. In summary research shows that:
Of course, reducing risk is not the same as eliminating a disease. Some people will probably develop cancer instead of heart disease and vice-versa.
Public health specialists look at the overall picture, though. They look at how a measure will affect the population at large. The evidence shows that measures to prevent heart disease should benefit health - perhaps enormously.
This chapter contains two charts. The first summarizes the major recommendations in this book. The second chart brings your diet in line with the recommendations of the cancer experts.
Summary Of Recommendations
A Guide To Substitutions For Healthier Meals
15 - Cookware For Cancer Prevention
You probably have decided to make some simple changes in your diet to try to reduce your risk of cancer. You know what foods to stock in your refrigerator and larder. But what about utensils and cookware? Certain cooking tools make good nutrition easier - and tastier. But the last thing that you should do is go out and spend a small fortune. So choose:
In addition to those listed above, the following items will make nutritious food simpler to prepare:
For Serious Cooks
If you spend a good deal of time cooking, you may want to acquire some of the following utensils. Make choices according to your eating habits. If you especially enjoy red meat, for instance, you might want to consider the following items:
If your passion is vegetables and cereals, think about one or more of these:
Finally, there is one expensive item that also deserves mention: a microwave oven. Some people, myself included, find that vegetables cooked in a microwave taste better than those cooked by traditional methods. Roasts and poultry also fare very well in a microwave. Cooking time, of course, is shorter, too.