Taking selenium supplements does not prevent heart disease in adults with a balanced diet, according to a systematic review published today in The Cochrane Library.
Current evidence is limited to healthy adults in the US but it does not support the view that the supplements reduce heart disease risk, researchers said.
They analysed data from 12 trials with a total of 19,715 participants and found that taking selenium supplements was not associated with a statistically significant difference compared to placebo in the risk of death due to heart disease or any other cause.
There was also no significant difference in the incidence of heart problems linked to taking selenium, the review found.
A slightly increased risk among those taking the supplements was noted in developing type 2 diabetes, although this was not deemed statistically significant either.
Alopecia and dermatitis were among the side effects noted by the research team.
The use of selenium supplements “in the primary prevention of heart disease in well-nourished populations” is not supported by the evidence, said Saverio Stranges of Warwick Medical School at the University of Warwick, Coventry, and one of the authors of the study.
“Taking selenium supplements is probably neither beneficial nor harmful, but given the lack of trials to date, we cannot rule out some low level of increased risk of type 2 diabetes, at least in individuals with high selenium status,” the author added.
With diet accepted as a key factor in the risk of developing heart disease, selenium has been put forward as a potential means of protecting against oxidative stress and inflammation.
For this reason, selenium is often given as part of efforts to lower heart disease risk but without extensive evidence showing it is effective.
There are concerns that individuals with high selenium status who consume excessive amounts of selenium could face a heightened risk of type 2 diabetes.