Selenium supplements for the prevention of cardiovascular disease

Use of selenium enriched foods, supplements and fertilizers has increased in recent years in many countries because of the perception that selenium may reduce the risk of cardiovascular disease and other chronic conditions. Therefore, it is important to understand the effects of a nutrient that is frequently supplemented on common conditions such as cardiovascular disease or diabetes. This review assessed the effects of providing selenium supplements to healthy adults in order to prevent the occurrence of cardiovascular disease. Whether selenium supplements would reduce the risk factors associated with heart disease was also examined. We found 12 trials in which 19,715 healthy adults were randomly assigned to receive selenium supplements or placebo. The vast majority of participants involved in these trials were male individuals from the US, where people are already well nourished and take large amounts of selenium from natural foods. Overall, the included studies were regarded as at low risk of bias. In our review, providing selenium supplements to healthy adults did not prevent the occurrence of major cardiovascular disease. The increased risk of developing type 2 diabetes when taking selenium supplements, as suggested in some previous studies, could not definitely be ruled out in our review. In summary, this review of the available evidence to date suggests that taking selenium supplements is neither beneficial nor harmful for cardiovascular disease, but it is probably unnecessary for those who are already well nourished and who take large amounts of selenium from natural foods.