Vitamin B6, also known as pyridoxine, has been known to medical science since the 1930s, and like the other B complex vitamins performs numerous functions which are essential for human health. A regular supply must be ensured from the diet because the vitamin can be neither synthesised nor stored in the body.

Vitamin B6 has probably attracted most attention from medical researchers and nutritional therapists as a means of reducing blood homocysteine levels, because an excess build up of this compound is well established as an indicator of an increased risk of cardiovascular disease. One European research project, for example, reported in 1997 that the risk was more than doubled in subjects who showed levels of blood homocysteine in the top 20% of the range revealed by the tests.

Vitamin B6 is known to operate together with vitamins B12 and folic acid to break down homcysteine into the harmless, and in fact beneficial, amino acids, methionine and cysteine; and the effect is potentially very significant. Some research in fact suggests that moderate supplementation with B6 may consequently reduce disease risk by as much as a third. But as important as this function of pyridoxine is, it's just one of the many health benefits it can offer; benefits which have led some practitioners to conclude that B6 may be the most vital of all the B complex vitamins.

On a general level, vitamin B6 is vital for the body's production of prostaglandins, hormone type compounds which are responsible for the proper operation of so many of the body's vital functions, including the blood supply and respiratory system, that imbalances are suspected to be a major cause of ill-health. Pyridoxine is also essential for the functioning of at least 100 enzymes governing such biochemical reactions as the manufacture of necessary proteins, genetic matter and amino acids; and the digestion of dietary carbohydrates and fats.

More specifically, good intakes of pyridoxine have been strongly linked to a robust immune system, particularly in older adults; whereas deficiencies appear to be directly correlated with a reduction the number of the body's T cells, the most vital for immune system function.

There is also evidence to suggest that vitamin B6 may help stabilise blood sugar and reduce the tissue and particularly eye damage which commonly follows the blood sugar problems associated with diabetes.

Vitamin B6 is also particularly associated with women's health, and is important in maintaining the correct balance of oestrogen and other female hormones. This relationship with the sex hormones has led to pyridoxine being used by some therapists as treatment for the depression that often accompanies the contraceptive pill. And more general depression is just one of the neurological disorders, along with epilepsy and impaired cognitive function for which B6 is claimed to be beneficial.

Vitamin B6 has been used for the relief of morning sickness in pregnancy since the 1940s, and is also believed to help alleviate pregnancy related high blood pressure. Vitamin B6 has also been used with some success in the relief of pre-menstrual tension and with the yeast growth, candidiasis. On the face of it, given its wide availability in common foods, the Western world should never see deficiencies of vitamin B6. But like the other B complex vitamins, it is all too easily removed from the body by the normal process of excretion. Intensive exercise, sweating, and the taking in of excessive fluids may therefore increase the body's requirement. The body's need for B6 also appears to be greater in proportion as it is comprised of lean, particularly muscle, tissue and more is required the more protein foods are consumed. So even orthodox opnion therefore acknowledges the probable benefit of supplementing with B6 at a level sufficient to ensure an intake of at least 2 mg per day. Some practitioners, however, recommend a normal target of 50 mg a day because of the wide ranging benefits attributed to the action of pyridoxine. But even higher doses of 100 mg may be recommended when attempting to tackle specific conditions. This kind of intake is in fact the suggested safe maximum suggested by the US Food and Nutrition Board, limits which are always set at very conservative levels; and the only toxicities observed from vitamin B6 intake have been in consequence of amounts very far in excess of this dosage.

But when taking B vitamins it needs always to be remembered that they are so closely dependent on each other that no single one of them can discharge its functions effectively in the absence of an adequate supply of each of the others. It is for this reason that the B complex vitamins are commonly found together in foods, and why any additional B vitamins should only be taken in the form of a supplement including the entire complex. Importantly as well, like all vitamins, those of the B complex operate best when in the presence of good quantities of all the nutrients required by the body. Most authorities therefore recommend that they be taken in conjunction with comprehensive multi-vitamin and mineral supplements, magnesium being particularly important in maximising the effect of vitamin B6.