You may have seen a concerning headline recently about dietary supplements. Research presented at the American Association for Cancer Research Annual Meeting suggested that taking supplements doesn’t curb cancer, and taking more than needed may actually drive up cancer risk. Specifically, researchers concluded that “taking more than the recommended daily allowance of folic acid, Vitamin E and beta-carotene were all shown to increase cancer risk.”
The interest in research on supplements and cancer began 20 years ago, when scientists observed that people who ate more fruits and vegetables tended to have less cancer. Researchers wanted to find out if taking supplemental doses of vitamins and minerals would further reduce the chances of developing various forms of this disease.
They found that in some human studies, cancer risk actually increased while taking supplements. For example, beta-carotene supplements tended to up the risk of both heart disease and cancer in people who smoke or drink heavily; and folic acid—which was thought to help reduce the number of polyps in a colon—increased the number in one trial.