Polyps are benign lesions in the large bowel that may turn cancerous, and tend to return after being removed. Earlier research showed selenium inhibited abnormal cell growth in the colon and rectum, doctors said.
In one study, 411 people, aged 25 to 75, had one or more previous polyps removed, were otherwise healthy, and did not take vitamins or calcium supplements. They took 200 mcg of a selenium-methionine compound, 30 mg of zinc, 6,000 IU of vitamin A, 180 mg of vitamin C, and 30 mg of vitamin E per day, or a placebo. After five years, compared to placebo, polyps were about 40 percent less likely to recur in the selenium group.