Research suggests how well high density lipoprotein (HDL) or good cholesterol functions is more important than having high levels of it.

High levels of HDL cholesterol has long been believed to protect against heart disease, however, a new study finds having high levels of it is not as important as, how well it is able to rid the body of excess cholesterol.

HDL cholesterol removes unwanted cholesterol from cells called macrophages and transports it to the liver to get rid of it. This clean up action prevents cholesterol from sticking to the arterial walls and leading to plaques, the hallmark of heart disease.

Low levels of HDL strongly associated with an increased risk of heart disease for so long, had experts perplexed for years why some people having high levels of HDL cholesterol still had a high risk of heart attacks. In fact, the trial of a drug that raised levels of HDL cholesterol i.e. torcetrapib, was halted in 2006, after it emerged taking it increased the risk of heart attacks and death.

This led researchers to surmise the way a person’s HDL functioned mattered more than having high levels of it.

In the study, researchers found participants having HDL cholesterol that was less able to remove cholesterol from the macrophages had thicker carotid arteries.

The study has been published in the 13th January issue of the New England Journal of Medicine.