Vitamins A and E are popularly believed to protect against cardiovascular disease and cancer. While studies have shown that people who eat diets rich in fruits and vegetables containing these vitamins have slightly lower incidences of these disorders, these investigations do not prove that the vitamins, and not something else in these foods, are responsible for any protective effect. A more meaningful study would carefully follow the result of taking a specific vitamin supplement. The Finnish Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study did just that--with surprising results.

Researchers monitored the health of 29,000 adult male smokers over a 6-year period. Each man received vitamin A or E, both vitamins, or neither. The endpoint of the study was to determine which men developed lung cancer. Not only did these vitamins fail to protect against this specific cancer, but the men who received beta-carotene actually had an increased incidence of lung cancer! In addition, neither vitamin lowered incidences of death from stroke or coronary heart disease.

The Finnish study has several limitations. Some critics claim that it was not conducted over a long enough time period. Also, the study considers only one type of person who engages in a dangerous activity--smoking--and may not account for all possible contributing factors to disease development. Unraveling the connections between specific nutrients and health is extremely complex, because of the many variables. Overall, a diet rich in fruits and vegetables is healthful. But the Finnish study shows that claims that certain vitamins protect against cancer or heart disease may be premature.

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