At the risk of sounding like a certain 20-something socialite, High-Density Lipoprotein (HDL) is hot! Advances in research have brought more attention to the blood lipid (or fat) we often call "good" cholesterol.
"Good" cholesterol doesn't refer to the cholesterol we eat in food, but rather to the high-density lipoprotein cholesterol circulating in our blood. It's one of the fats measured in the lipid panel blood test doctors perform. And it's the component you want more of, because a higher HDL is associated with a lower risk of heart disease.
In every issue of WebMD the Magazine, we ask experts to answer readers' questions about a wide range of topics, including some of the most cherished medical myths out there. For our June 2012 issue, we asked a New York-based cardiologist about chest pain and heart attacks.
Experts from the National Cholesterol Education Program (NCEP) note that although LDL or "bad" cholesterol has gotten most of the attention, there's growing evidence that HDL plays an important role.
Facts About "Good" Cholesterol
HDL cholesterol normally makes up 20%-30% of your total blood cholesterol.
There is evidence that HDL helps protect against the accumulation of plaques (fatty deposits) in the walls of coronary arteries.
Research suggests that a five-point drop in HDL cholesterol is linked to a 25% increase in heart disease risk.
In prospective studies -- that is, studies that follow participants for a period of time to watch for events like heart attacks or death from heart disease -- HDL usually proves to be the lipid risk factor most linked to heart disease risk.
HDL cholesterol levels are thought to be impacted by genetics.
Women typically have higher HDL cholesterol levels than men. About a third of men and about a fifth of women have HDL levels below 40 mg/dL. Doctors consider levels of less than 40 mg/dL to be low.
Researchers from the Netherlands who analyzed 60 studies concluded that the ratio of total cholesterol to HDL (in which your total cholesterol number is divided by your HDL number) is a better marker for coronary artery disease than LDL measurement alone.
"Boosting HDL is the next frontier in heart disease prevention," says P.K. Shah, MD, director of cardiology at Cedars-Sinai Medical Center in Los Angeles. Shah says that if the new drugs designed to increase HDL levels prove effective, they could potentially reduce the number of heart attacks and strokes by 80% to 90% -- and save millions of lives. HDL-boosting drugs are now being tested.
How Does HDL Cholesterol Help Your Heart?
Experts aren't yet sure exactly how HDL cholesterol helps reduce the risk of heart disease. But a few possibilities have emerged.
The NCEP says that high HDL levels appear to protect against the formation of plaques in the artery walls (a process called atherogenesis), according to studies in animals.
Lab studies, meanwhile, suggest that HDL promotes the removal of cholesterol from cells found in plaques, or lesions, in the arteries.
"Recent studies indicate that the antioxidant and anti-inflammatory properties of HDL also inhibit atherogenesis," says the NCEP report.