To the Editor.—
Dr Herbert's1 review of Ms Hausman's The Right Dose: How to Take Vitamins and Minerals Safely wisely points out the dangers of consuming high doses of vitamin and mineral supplements. In particular, he takes Ms Hausman to task for not mentioning the potential teratogenic effects of 25 000 IU of vitamin A in pregnant women. A recent large-scale epidemiologic study2 lends further support to Dr Herbert's position on the danger of large doses. Martinez-Frias and Salvador2 have found a correlation between doses of 40 000 IU or more of the vitamin and congenital malformations.Most nutritionists recognize that Americans can obtain the recommended dietary allowances (RDA) for virtually all essential nutrients from a well-balanced diet. However, in all fairness to Ms Hausman, a case can be made for the value of low-dose supplementation among healthy persons—a viewpoint that Dr Herbert dismisses out of hand.
Cerrato PL. Recommended Dietary Allowances for Vitamins. JAMA. 1988;260(9):1242–1243. doi:10.1001/jama.1988.03410090070028