October 14, 2011
Louis Potters, MD, Chair of Radiation Medicine
Louis Kavoussi, MD, Chair of Urology
Last week, results from the SELECT Trial were released. This randomized study of 35,533 men tested the hypothesis that Vitamin E and selenium could prevent prostate cancer. Surprisingly, the results just published in the Journal of the American Medical Association not only found that the supplements had no effect on the development of prostate cancer, but also that there was a 17 percent increased incidence of cancer in men taking the supplements.
This follows on the heels of a report from the Archives of Internal Medicine that showed that older women who use daily dietary supplements, especially with iron, had a higher mortality rate compared with those who did not take vitamins.
There are several potential explanations for these results.
- First and most unfortunately, one can never know exactly what is in each supplement. Because the supplement industry is completely unregulated in the US, no government agency analyzes batches to assure correct dosing -- let alone correct ingredients. Indeed, there have been cases where individuals who analyzed questionable supplements found that the products contained prescription drugs not listed on the label.
- Another explanation is that more is not always better. More sugar, more fats, more proteins have been shown to be detrimental to health. This too may also hold true for vitamins.
- Finally and perhaps most importantly, in nature, vitamins are not supplied as a singular entity. For instance, an orange contains Vitamin C and also has multiple nutrients that likely work together to provide a beneficial effect.
Supplements may have a role in treating specific conditions, such as using iron to treat types of anemia. However, routine use of supplements to prevent diseases such as prostate cancer may actually be harmful. The best prevention is to heed the advice of our mothers: “Eat your vegetables.”