VITAMIN B6
OVERVIEW:
B6 is required for the proper functioning of more than sixty enzymes and is essential for normal nucleic acid and protein synthesis. It plays a role in the multiplication of all cells and the production of red blood cells and the cells of the immune system. Through its effects on various minerals and brain neurotransmitters, it influences the nervous system.
Severe B6 deficiency can result in anaemia, nervous disorders and various skin problems. It has been claimed that women have special need of B6; while on the Pill, during pregnancy and in order to alleviate, some of the symptoms of premenstrual tension. Recently some very, preliminary evidence has emerged that suggests a possible anti cancer role for B6.
Even more important may be the role B6 plays in immunity. In fact, of all the B vitamins, B6 is most crucial for a healthy immune system.
VITAMIN B6 CLAIMS
Positive:
3. Relieves the symptoms of premenstrual tension and cures some forms of infertility
4. Has anti-convulsant effects and protects against nervous disorders
6. Protects against metabolic imbalances caused by oral contraceptives
Negative:
1. Toxic in high doses and may cause serious nerve damage
2. Reduces the therapeutic effect of levodopa, a drug used by sufferers of Parkinson's disease
EVIDENCE
Related To Positive Claims:
1. Boosts immunity : - Laboratory animals and human volunteers subjected to B6 deficiencies experience severe immune depression. Many older people and alcoholics have low levels of B6 and both groups are more likely to have weakened immunity.
So are people suffering from diseases characterised by immune disorders, such as AIDS and many cancers.
Recently it has been shown for the first time that B6 supplements can boost immunity in the elderly. And when lab animals with cancer are fed B6 rich diets their immune responses increase and the growth of their tumours slows.
The time is at hand to test B6 in people suffering from cancer and immune disorders.
2. Protects against cancer : - B6 has been found to inhibit the growth of a number of different types of cancer cells in the laboratory. Mice given B6 (in the form of pyridoxal) and then injected with melanoma cells, of the sort that appear in a particularly lethal form of skin cancer, exhibited significantly greater resistance to this cancer than did control mice that did not receive pre treatment with B6. The vitamin treated mice had more than a twofold reduction in tumour growth compared to the control animals.
Similarly promising results with human melanoma cells treated with B6 in culture prompted researchers to test the effects of B6 in a human subject with melanoma. The B6 was administered in the form of a pyridoxal cream that was applied directly to the malignant nodules, both cutaneous and subcutaneous, four times daily for a two- week period.
At the conclusion of this trial cutaneous papules were no longer visible and the subcutaneous nodules were significantly reduced in size (some nodules showing more than 50 percent regression). All of this must be accounted encouraging, especially in view of the fact that melanoma has heretofore resisted almost all form of treatment. More investigation is urgently needed in order to further assess these exciting but still very preliminary findings.
3. Relieves the symptoms of premenstrual tension and cures some forms of infertility . It has been claimed for some time that B6, can relieve various discomforts to which some women fall prey Various disturbances of estrogen metabolism are claimed to be corrected with supplemental B6.
Premenstrual tension, often characterized by breast tenderness, headaches, weight gain due to water retention, and irritability arising in the week to ten days prior to menstruation is a significant problem for many women.
This syndrome has been attributed to a variety of hormonal processes, some of which are known to be affected by B6. It has been reported that twenty one of twenty-five women given 500 milligrams of B6 daily, in time release tablets, in a double-blind study enjoyed significant relief from premenstrual symptoms.
Treatment continued through three consecutive menstrual cycles. These researchers have also reported that women with unexplained infertility experienced a high conception rate after B6 therapy was started.
Another study showed that B6 is effective in alleviating the dizziness and nausea that usually accompany premenstrual syndrome. The impact on depression and anxiety were less, but those who got B6 were less likely to withdraw from social activities than were control subjects who got placebos instead of B6.
4. Has anti-convulsant effects and protects against nervous disorders . It is established that B6 deficiency can cause convulsions and degeneration of peripheral nerves. In fact, it was through the administration of high doses of B6 to infants suffering from convulsions that researchers demonstrated, in 1954, the first of many inborn vitamin responsive disorders of metabolism. B6 supplementation dramatically abolishes seizures in most of these infants.
A neurotransmitter in the brain thought to inhibit certain types of seizures depends in part for its existence upon adequate supplies of B6. Except in these cases of inborn metabolic disorder, however, there is no evidence to support the claim that B6 is effective against convulsive seizures in general.
Evidence is mounting that B6 supplementation may be the best treatment for carpal tunnel syndrome, a compression of a nerve in the wrist that causes a pins and needles sensation and often quite a lot of pain in the hand. The old treatments, injecting the wrist with steroids, splinting the wrist and giving other anti inflammatory drugs - havent proved very useful in most cases. B6, on the other hand, has proved quite effective in a large majority of patients getting 100 to 200 milligrams of B6 per day. It sometimes takes three months of B6 therapy before most symptoms disappear.
5. Helps control diabetes - There is some evidence that some forms of diabetes may be contributed to by B6 deficiencies.
Adequate levels of B6 are required for the proper metabolism of the amino acid tryptophan. Abnormalities of tryptophan metabolism, which may contribute to glucose intolerance, have been reported in some diabetics, and these abnormalities have been found to be reversible with administration of supplemental B6.
Supplemental B6 can reduce the need for insulin in some diabetics. Other research suggests that supplemental B6 can enhance carbohydrate tolerance during pregnancy, when diabetes can pose special risks. Dont use supplemental B6 in this context unless directed to do so by your doctor.
6. Protects against metabolic imbalances caused by oral contraceptives - Women who take oral contraceptives usually exhibit abnormalities of tryptophan metabolism of the sort discussed under diabetes. These abnormalities have been at least partially corrected by administration of supplemental B6, with resulting improvement in carbohydrate (sugar) tolerance. Daily intake of 5 milligrams of B6 is generally adequate to overcome this abnormality caused by oral contraceptives, making it clear that the megadoses of this vitamin that are often recommended during pregnancy by enthusiasts are not justified.
7. Prevents skin disease : Claims that large doses of B6 can clear up acne and dry, itching skin have been made for some time, but without objective support. B6 may help clear up some skin problems but only if there is a severe B6 deficiency to begin with.
8. Inhibits cataracts - It has been suggested that a number of B vitamins may help protect the lenses of the eyes from the clouding effects of cataracts. Research remains very preliminary and, though some positive data may turn up, this claim remains unproved at this time.
Related To Negative Claims:
1. Toxic in high doses and may cause serious nerve damage .
Researchers have reported nerve damage in seven patients who had been taking 2 grams or more of B6 daily. Four of the seven patients had been taking these doses for only two to four months.
The first signs of neuro-toxicity in most of these patients were unstable gait and numbness in the feet, followed by numbness and clumsiness in the hands. Extensive evaluations ruled out the presence of other or additional toxic substances.
These patients gradually improved when B6 was withdrawn, though some sensory deficits remained.
The commonest reason given for taking these large doses was for relief of premenstrual edema (water retention). Clearly, it is unwise to megadose on B6.
2. Reduces the therapeutic effect of levodopa, a drug used by sufferers of Parkinson's disease :- Vitamin B6 is involved in the metabolism of L-dopa. If L-dopa is given by mouth, as is the case with patients suffering from Parkinsons disease, the L-dopa is inactivated by vitamin B6 in the intestine and loses its effectiveness. Therefore, patients taking L-dopa should not consume supplementary B6 at the same time (unless the L-dopa drug taken is Sinemet, in which case its okay to take B6 at the same time).
RECOMMENDATIONS
(A) Suggested Intake:
The FDAs Recommended Daily Allowance is 2 milligrams for adults. Healthfood stores typically sell B6 in 50 to 500 milligram tablets. It is easy to see how an unwary consumer might soon be taking potentially highly dangerous doses of this nutrient four 500 milligram tablets and youre taking 2 grams a day, the same mount that resulted in significant nerve damage in several patients.
There is little in the data to justify dosages of B6 in excess of 50 milligrams daily. That is more than an ample dose for adults, including women who are pregnant or on the Pill. Women who see relief from the symptoms of premenstrual tension or those seeking to alleviate diabetes, symptoms of the carpal tunnel syndrome or any other disorder should consult their doctors before exceeding 50 milligrams of supplemental B6 daily.
(B) Source / Form: Dietary sources of B6 include meats, whole grains and brewers yeast.
(C) Take With:
Get your supplemental B6 in a well- balanced vitamin / mineral formula.
(D)
Dont use B6 at the same time with levodopa, the anti Parkinsons drug. (It is okay, though, to take with Sinemet.) Discontinue B6 if any signs of toxicity occur, such as numbness in the hands or feet or unsteadiness in walking. Do not exceed 50 milligrams of supplemental B6 daily.
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