The antioxidant - an enzyme called glutathione peroxidise, or GPx3 - can dramatically reduce the risk of cardiovascular disease and heart attack. People with high levels of GPx3 were six times less likely to have heart problems, say researchers from the University of Minnesota Medical School.
The antioxidant is found in fruit, vegetables and Brazil nuts, and appears to have the same protective effect as a statin drug, which promotes the 'good' HDL (high-density lipoprotein) cholesterol while lowering levels of 'bad' LDL cholesterol.
Low levels of GPx3 and HDL cholesterol put one in four adults at risk of a fatal heart attack, the researchers reckon.
Eventually, they hope that analysing levels of GPx3 in blood tests will become a standard way of assessing heart attack risk.
(Source: PLoS One, 2012; 7: e38901).