The Journal of the American Medical Association (JAMA) Reverses its Position on Vitamin Supplements

Reversing a longstanding policy on vitamin supplements, the Journal of the American Medical Association announced last month that it will begin advising all adults to take at least one multivitamin pill each day (1). The last time the journal made a comprehensive review of vitamins, about twenty years ago, it concluded that normal people shouldn't take multivitamins. Most people, it was believed, could obtain adequate amounts of these nutrients from their diet.

According to Drs. Fletcher and Fairfield of Harvard University who wrote JAMA's new guidelines, "most people do not consume an optimal amount of all vitamins by diet alone". "Sub-optimal intake of some vitamins, above levels causing classic vitamin deficiency, is a risk factor for chronic diseases and common in the general population, especially the elderly." The authors emphasize that dietary improvement is a central component of an overall program of preventive care, while acknowledging that it is often difficult to get individual patients to change their dietary patterns.

In their scientific review (2), Fletcher and Fairfield highlight the relationship of B vitamin intakes to cardiovascular disease, neural tube defects, and colon and breast cancer, as well as that of vitamin D to osteoporosis. They also state that low levels of antioxidant vitamins (A, E, and C) may increase the risk of several chronic diseases. Vitamin E and the carotenoid lycopene, for example, may decrease the risk of prostate cancer.

The authors point out that some supplements may not be appropriate for all sub-groups of the population. For instance most multivitamins contain iron, which may not be advisable for adult men and non-menstruating women, given the high prevalence of the gene for hemochromatosis (iron overload). Additionally, some supplements contain amounts of preformed vitamin A that should be avoided during the first trimester of pregnancy.

References

1. Fletcher RH and Fairfield KM. Vitamins for chronic disease prevention in adults: Clinical Applications. JAMA, June 19, 2002; 287:3127-129.
2. Fletcher RH and Fairfield KM. Vitamins for chronic disease prevention in adults: Scientific Review. JAMA, June 19, 2002; 287:3116-126.
3. Stevens LM et al. JAMA Patient Page : Vitamins A to K. JAMA, June 19, 2002.