The Epidemiology of Selenium and Human Health

Abstract

Few issues involving nutritional and environmental epidemiology have received as much interest as the relation between selenium (Se) intake and human health, as reflected by the large body of evidence from observational and experimental studies with reference to cancer and other clinical endpoints. Se deficiency may play a major role in favoring the onset of a human cardiomyopathy, Keshan disease. Se overexposure has been linked to skin and advanced prostate cancers in recent randomized controlled trials, in contrast with earlier hypotheses of protective effects of Se intake against cancer generally, and prostate cancer in particular. Overexposure has also been linked to higher risk for diabetes and amyotrophic lateral sclerosis. For cardiovascular disease risk, such as ischemic heart disease and stroke, little evidence of any modifying effect of Se exposure has been provided by epidemiologic studies. The results of these studies should be used in public health to set better standards for intake of organic and inorganic Se species, focusing on experimental studies with individual Se compounds more than overall exposure to the element, in order to improve reliability and reduce bias in the studies.