Ron was a vegetarian of normal weight who logged 25 to 30 miles a week running. He was shocked when the quick cholesterol test he took at a health fair gave him a total cholesterol reading of 196 milligrams/deciliter, perilously close to the 200 level regarded as “high cholesterol.”

Ron’s doctor reserved judgment until he got results from a 12-hour fasting blood lipid profile that includes measurements of LDL, HDL and triglycerides. As he suspected, Ron had a very good HDL reading of 75, confirming a low risk of heart disease.

HDL is considered protective of the heart in several ways. Its most important role may be what’s known as reverse cholesterol transport — moving LDL cholesterol out of blood vessels before it can form fatty deposits. 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 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 factor 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.

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 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 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: 1. aerobic exercise, 2. weight loss and 3. not smoking.

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 amount of monounsaturated fats (olive oil, canola oil, avocados) are some polyunsaturated fats 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.

Medications are for persons who cannot lower their risk enough through lifestyle measures alone. But while statins and other cholesterol-lowering medications are very good at lowering the bad cholesterol, they are less effective at increasing the good. 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.

Hopes for an effective medication to specifically affect HDL cholesterol were dashed in late 2006. Toretrapid, 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.

For the foreseeable future, it won’t be possible to protect yourself from heart disease simply by taking a pill, or even by denying yourself all dietary fats. The lifestyle needed to keep HDL levels elevated remains the best way to keep your heart healthy.



Rupp is information and assistance case manager with the Northern Oklahoma Development Authority Area Agency on Aging.