HDL also helps keep blood vessels dilated and is believed to have anti-clotting, antioxidant and anti-inflammatory effects. Keeping HDL high is now considered at least as important as keeping LDL low.
According to guidelines of the National Cholesterol Education Project, HDL should be at least 40 mg/dL (50 for a female), and anything lower is abnormal and considered an independent risk for heart disease. Even in persons with normal or very low LDL and total cholesterol, the risk of heart disease is increased when HDL is too low.
And paying attention to your HDL can pay big dividends. Whereas lowering LDL by one mg/dL lowers the risk of cardiovascular disease by one percent, raising HDL by the same amount results in a two to three percent reduction in risk.
It’s the Package That Counts
What’s “good” about HDL is not the cholesterol but the package in which it comes. As the name suggests, it’s a very dense molecule consisting of protein, lipids (fats) and cholesterol.
Recent laboratory studies have shown that this lipoprotein changes shape very quickly, within microseconds, collecting lipids into a disk and, eventually, a sphere, with two protein belts encircling the fat. The fatter the sphere, the better because this molecule works like a dump truck, loading itself with hazardous fats and transporting them back to the liver where they are dumped for further processing.
At any one time, there are HDL molecules of varying size–from empty to full–going about their job of sweeping the arteries clean. With HDL, size really does matter.
If you have high levels of HDL, you are likely to have relatively low levels of LDL because the excess is constantly being carried away by the good guys in dump trucks. Total cholesterol, however, could be moderately higher because that number includes HDL.
Most lifestyle changes Americans have been taught to make to protect themselves against heart disease are also good ways to increase HDL. These include:
aerobic exercise,
weight loss and
not smoking.
Aerobic exercise is anything that increases the heart rate for 30 minutes or more at a time such as running, biking, swimming or brisk walking. The more exercise the better when it comes to HDL.
Obesity tends to lower HDL, just as it raises LDL and triglycerides. Weight loss, particularly when it results in a decrease in abdominal obesity, is another effective way to increase HDL cholesterol. A weight loss of six pounds should raise HDL by at least one mg/dL.
For smokers, a successful effort to quit may raise HDL by 15 to 20 percent–at least as much as can be gained through the best medications now available.
Dietary advice for raising HDL takes a slightly different direction. Heart-healthy still means low fat, if you’re talking about saturated fats and trans fats. But for improved HDL, moderate amounts of monounsaturated fats (olive oil, canola oil, avocados) and some polyunsaturated fats are recommended.
A HDL-healthy diet has a Mediterranean slant–fruits, vegetables, whole grains, beans and nuts. Onions and foods high in soluble fiber (oats, apples, citrus fruits and legumes) are believed to be beneficial.
Olive oil, nuts and nut oils might push the total fat content to 25 to 35 percent of calories, but they may also keep your heart healthy by boosting HDL cholesterol. Fatty fish such as salmon, rich in omega-3 fatty acids, may also be beneficial.
Alcohol in moderation is known to increase HDL so two to six ounces of wine with your evening meal might be a pleasant way of pretending you’re in the south of France or the hills of Tuscany. Medical groups are quick to warn about the risks of over-consumption and alcoholism.
Drugs Not the Answer
Medications are for persons who cannot lower their risk enough through lifestyle measures alone. But while cholesterol-lowering medications are very good at lowering the bad cholesterol, they are less effective at increasing the good. Three drug categories can be used to reduce HDL cholesterol. These include statins, fibrates, and niacin.
Statins raise HDL by only 5 to 8 percent. Bigger increases can be achieved with fibrates such as gemfibrozil and fenofibrate (10 to 15 percent) and niacin (15 to 30 percent). Hopes for an effective medication to specifically affect HDL cholesterol were dashed in late 2006. Torcetrapid, a drug developed by Pfizer, was thought to be capable of bringing about increases of 50 to 60 percent, but testing of this drug was stopped when more deaths than expected occurred in subjects taking the drug in combination with a statin.
Other HDL-raising drugs are under development, but it’s unknown whether they might have the same problem that plagued torcetrapid. It’s now believed possible to raise HDL too much–that the good cholesterol may be beneficial in a U-shaped rather than a linear pattern.
For the foreseeable future, it won’t be possible to protect yourself from heart disease simply by taking a pill, nor even by denying yourself all dietary fats. The lifestyle needed to keep HDL levels elevated remains the best way to keep your heart healthy.
Michelle Herbert Thomas, PharmD, CDE
Clinical Director
