HDL is the so-called “good” cholesterol. Like Lance Armstrong, HDL has been a hot topic in the news recently—also for all the wrong reasons.
Scientists have long sought ways to increase the body’s level of HDL in hopes of preventing heart attacks. The problem is that the new drugs designed for raising HDL levels have failed to improve the health of the people participating in clinical trials. Hundreds of millions of dollars have been spent on pharmaceutical development but, as of right now, the drug companies don’t have much to show for the investment.
Should we stop calling HDL the “good cholesterol”?
Not so fast. To help make sense of the HDL dilemma, I tracked down Dr. Seth Martin, an international HDL expert at the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease.
Dr. Blaha: Seth, what is HDL cholesterol?
Dr. Martin: “HDL” stands for “high-density lipoprotein,” a fat-like substance that circulates in our blood. Rather than depositing cholesterol in our blood vessels in the form of plaques, however, HDL carries cholesterol away from the arteries in a process called “reverse cholesterol transport.” Therefore, HDL is considered “good” cholesterol. In the clinic, we evaluate HDL cholesterol by using a blood test that measures the amount of cholesterol that is attached to HDL in the body and then is carried back to the liver.
Dr. Blaha: What is the evidence that HDL cholesterol is good for you?
Dr. Martin: As early as the 1950s, researchers found that people with higher HDL cholesterol were less likely to have coronary heart disease. This was confirmed over the ensuing decades in multiple large-population survey studies of both men and women. In addition, laboratory experiments showed that HDL not only shuttles cholesterol away from arteries, but also lowers inflammation, fights infections, and lessens abnormal blood clotting.
Dr. Blaha: How can a person raise their HDL cholesterol?
Dr. Martin: Perhaps half of your HDL comes from your genes—something we have no control over—but we can still raise our HDL levels by making lifestyle improvements. For smokers, this means quitting smoking. For couch potatoes, it means exercising more—improving fitness raises HDL pretty consistently. For heavy people, it means achieving at least a 10-percent weight loss. When patients come to the Johns Hopkins Ciccarone Center, we really emphasize the importance of lifestyle and we work personally with each individual to make sure they achieve life changes that will assure success.
Dr. Blaha: Tell me about the recent clinical trials that have tested new drugs developed to raise HDL levels.
Dr. Martin: The recent clinical trials, which tested whether heart attacks decrease when patients take drugs drugs that cause HDL to go up, have been disappointing. New drugs called CETP inhibitors, torcetrapib, and dalcetrapib either made no difference or may have even increased health problems.
Many patients were already taking niacin too, also known as nicotinic acid or vitamin B3, because they’d heard it raises HDL, but niacin also did not help in two recent trials in which patients were taking niacin along with cholesterol-lowering drugs called statins. Both of these trials were very complicated, and so the experts are still working to make sense of the results.
Dr. Blaha: What should patients do if they have low HDL?
Dr. Martin: Low HDL is commonly a sign of something called metabolic syndrome, which is a "disease of lifestyle;" that is, it’s a disorder that should first be fought by adopting a healthier lifestyle, not through the use of drugs. If your doctor determines that you remain at risk for heart disease, the treatment of choice is a statin, not an HDL drug. And if you are already taking niacin, please don’t stop it without talking to your doctor, because niacin also lowers bad cholesterol and the verdict is still out on its effect on heart health!