Non-nutritional uses of vitamin B-6

Vitamin B-6 is a water-soluble vitamin, and is readily metabolized and excr eted, so it has generally been assumed to have negligible toxicity, althoug h at very high levels of intake it can cause peripheral nerve damage. Nutri tional deficiency disease is extremely rare, although a significant proport ion of the population shows biochemical evidence of inadequate status, desp ite apparently adequate levels of intake. The vitamin has been used to trea t a wide variety of conditions, which may or may not be related to inadequa te intake. In some conditions use of vitamin B-6 supplements has been purel y empirical; in other conditions there is a reasonable physiological or met abolic mechanism to explain why supplements of the vitamin many times great er than average requirements may have therapeutic uses. However, even in su ch conditions there is little evidence of efficacy from properly conducted controlled trials.