University of Colorado Cancer Center investigator Tim Byers, MD, MPH, has research that indicates that over-the-counter supplements may actually increase cancer risk if taken in excess of the recommended daily amount. Taking extra vitamins and minerals may do more harm than good.
This research started 20 years ago with the observation that people who ate more fruits and vegetables tended to have less cancer. Researchers wanted to see if taking extra vitamins and minerals would reduce cancer risk even further. Thousands of patients were studied for ten years who were taking dietary supplements and placebos. Some people actually developed more cancer while on the vitamins.
Through his analysis, Byers found that people who took high doses beta carotene supplements had an increased risk for lung cancer. Selenium supplements were associated with skin cancer. Men who took vitamin E had an elevated risk for prostate cancer. Folic acid, a B vitamin, taken in excess could lead to an increased risk for colon cancer. His research shows that people should not take supplements at levels higher than what you can get in your diet. Byers and other experts urge people to incorporate more fruits and vegetables into their diet, rather than relying on supplements.
A person who has a known deficiency of a certain vitamin or mineral, either due to diet or health condition that prevents proper absorption should take a supplement, preferably a multivitamin that provides levels in line with recommended daily allowances. But in every case, Byers cautions consumers to acknowledge that there may be harm in excess.
People need to be take vitamins and minerals at the correct dosage. There is no substitute for good, nutritional food.
People can get the daily recommended doses of vitamins and minerals in their diets by eating healthy meal and many adults who take vitamin supplements may not need them. We should really consider better regulation of these nutritional supplements.