Over the past few decades, scientists have suggested that high levels of HDL — which has come to be known as "good cholesterol" — can reduce the risk of heart attack. New evidence, however, suggests that might not be the case after all.
The study, which appears in the The Lancet, challenges existing assumptions that high levels of HDL reduce the risk of heart disease. Those assumptions are based, largely, on the fact that low levels of HDL are definitely associated with higher risk of heart attack.
But a team of scientists from the Broad Institute and Massachusetts General Hospital studied links between genetic variations, HDL levels and heart attacks in over 170,000 individuals and found no evidence to suggest that HDL reduces risk of heart disease. Sekar Kathiresan, associate professor of medicine at Harvard Medical School and one of the researchers, explains to Science Daily:
"It's been assumed that if a patient, or group of patients, did something to cause their HDL levels to go up, then you can safely assume that their risk of heart attack will go down. This work fundamentally questions that."
What the research certainly does not deny is that low levels of HDL are a good predictor of future heart disease. Actually, HDL is a great indicator and will continue to be used to identify patients at high risk of cardiovascular disease. However, the study does suggest that any attempts to artificially boost HDL levels seem rather pointless. Kathiresan goes on to explain:
"[W]e have shown that you cannot assume that raising HDL by any mechanism will help patients. Perhaps other mechanisms exist that can lower risk, but we will need to keep searching for them."