Vitamin and Mineral Supplements: As Good as They Sound?

Food & Drink Weekly, Feb 7, 2000

Many U.S. consumers take vitamin and mineral supplements because they hope or believe supplements will help prevent such diseases as cancer, heart disease and osteoporosis. However, recent scientific claims that taking supplements of specific nutrients such as vitamin C, vitamin E, beta-carotene and calcium may be protective is not wholly convincing, according to the American Council on Science and Health, Inc. (ACSH). In its latest report, Vitamins and Minerals: Does Epidemiologic Evidence Justify General Supplementation?, ACSH says there is strong evidence that a diet rich in fruits and vegetables containing these nutrients can lower the risk of disease.

Supplementation can be prudent in a variety of situations. For example, during early pregnancy folate supplementation can help prevent some birth defects. Supplementation can, however, involve risks: toxicity from large doses of certain nutrients, negative interactions between nutrients, and a false sense of security about the adequacy of a supplemented diet. ACSH says because foods are complex mixtures of many substances, it is not clear that the nutrients currently promoted as protective are really the most important or effective ones.

Much of the scientific evidence suggesting that vitamins and minerals may prevent disease stems from epidemiological studies that document lower rates of heart disease and cancer in populations with high consumption of fruits and vegetables. Because these foods are rich in vitamins and minerals, many assume that supplements of these nutrients can decrease the risk of disease, ACSH explained. The data do not support this approach, and large, well controlled clinical trials of supplements in healthy people do not show significant benefits, according to ACSH. For healthy people, the report emphasizes the most important nutritional advice is to consume a diet that is moderate in calories and fat and contains a balanced and varied selection of foods. The bottom line is, mom was right: eat your fruits and vegetables.