Too much of the essential mineral selenium in diet can increase a person's cholesterol level by almost 10 percent, says a new study from the University of Warwick.
Selenium is a trace essential mineral with anti-oxidant properties. The body naturally absorbs selenium from foods such as vegetables, meat and seafood.
But, if the balance is altered and the body absorbs too much selenium, such as through taking selenium supplements, it can have adverse affects.
Led by Dr Saverio Stranges at the University's Warwick Medical School, researchers have found that high levels of selenium are linked with increased cholesterol, which can cause heart disease.
The researchers examined the association of plasma selenium concentrations (levels of selenium in the blood) with blood lipids (fats in the blood).
They found that participants with higher plasma selenium had an average total cholesterol level increase of 8 percent.
They also noted a 10 percent increase in non-HDL cholesterol levels (lipoproteins within your total cholesterol that can help predict the risk of someone suffering a heart attack or chest pain).
In addition, among the participants with the highest selenium levels, 48.2 percent admitted they regularly took dietary supplements.
The study was conducted among 1042 participants aged 19-64 in the 2000-2001 UK National Diet and Nutrition Survey.
Stranges said that although high selenium levels were not exclusively caused by people taking dietary supplements, the results of the study were important because the use of selenium dietary supplements had risen considerably in the UK in recent years.
He said this was largely due to the perception that selenium can reduce the risk of cancer and other diseases.
"The cholesterol increases we have identified may have important implications for public health. In fact, such a difference could translate into a large number of premature deaths from coronary heart disease.
"We believe that the widespread use of selenium supplements, or of any other strategy that artificially increases selenium status above the level required is unwarranted at the present time," he added.
The study was recently published in the Journal of Nutrition.