A mineral high in antioxidants and proven to be a key ally in the fight against cancer may cause high cholesterol and increase the risk of heart disease if taken too much.

The study published in the Journal of Nutrition found that high levels of selenium were associated with increased cholesterol.

Researchers followed 1,042 participants aged 19 through 64 in England. They were interviewed on their lifestyles and eating habits and had blood samples taken. They found that the subjects with the highest levels of selenium in the blood had an average of 8 percent higher cholesterol than those with smaller levels of the mineral in their blood.

In addition, 48 percent of the study participants with the highest selenium levels admitted to regularly taking selenium supplements.

Selenium is found naturally in foods like vegetables, meats and seafood. The popularity of selenium supplements has increased in recent years due to the mineral’s antioxidant and cancer-fighting benefits.

"This use has spread despite a lack of definitive evidence on selenium supplements efficacy for cancer and other chronic disease prevention," said lead researcher Dr Saverio Stranges. "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," he added.