Benefits of Nutritional Supplements Evident a Decade Later
The General Population Nutrition Intervention Trial was a randomized cancer prevention trial involving 29,584 participants conducted from 1985 to 1991. The trial tested the effects of supplements on the risk of esophageal and gastric cardia cancer on residents of Linxian, China, who have some of the highest cancer rates in the world. Treatment with “factor D,” a combination of 50 µg selenium, 30 mg vitamin E, and 15 mg beta-carotene, led to decreased mortality from all causes, overall cancer and gastric cancer. In the present paper, researchers present results of 10-year follow-up after the end of the original trial.
From the beginning of the trial through May 2001, 9,727 deaths occurred, including 3,242 from cancer, 1,515 from esophageal cancer, and 1,199 from gastric cancer. 10 years after the end of the trial, participants who took factor D still had a 5% reduction in total mortality and 11% reduction in gastric cancer. The greatest benefit was observed among participants younger than 55 years old, who also experienced a 17% reduction in esophageal cancer.
The beneficial effects of selenium, vitamin E, and beta-carotene on mortality and cancer risk were still evident up to 10 years after completing the supplement trial and were consistently greater in younger participants. The results of the follow-up validate the original trial findings and indicate that even short-term supplementation may result in long-term benefits.