Why is some cholesterol called “good” (HDL – helpful to the heart) and other cholesterol called “bad” (LDL – harmful)?
Cholesterol travels through the bloodstream in protein packages called lipoproteins. The lipoprotein of greatest concern is low-density lipoprotein (LDL). If your body produces more LDL than the cells can absorb, it lodges in artery walls and contributes to the buildup of atherosclerotic plaque.
Driving down LDL has been the main target for improving cholesterol levels according to a report from the Harvard Medical School. Powerful cholesterol-lowering drugs called statins are available to do just that. Studies have shown that taking a statin can cut the risk of developing and dying from heart disease by 30% to 40%.
But there’s more to the story of cholesterol and cardiovascular risk than LDL. Another key player is high-density lipoprotein (HDL), dubbed the “good” cholesterol. HDL removes LDL from the artery walls and ferries it back to the liver for processing or removal.
How HDL helps
Cholesterol travels in the blood attached to lipoproteins. Low-density lipoprotein (LDL) enters the walls of arteries, where it contributes to the buildup of atherosclerotic plaque. High-density lipoprotein (HDL) removes LDL from the artery walls and carries it back to the liver. HDL also helps quell inflammation and protect the cells lining the arteries’ inner surface (endothelium).
HDL also acts as:
An antioxidant. Researchers believe antioxidants can protect against coronary artery disease by preventing LDL cholesterol from reacting with oxygen, which leads to the progressive thickening and hardening of the walls of arteries.
An anti-inflammatory. Though inflammation is an essential part of the body’s defenses, it can cause problems, too. In the heart, inflammation can trigger atherosclerosis, keep the process smoldering, and influence the formation of artery-blocking clots, the ultimate cause of heart attacks and many strokes.
An antithrombotic. Thrombosis is the forming of clots, and preventing these clots from forming in the coronary arteries can prevent heart attack and stroke.
People with low levels of HDL are more likely to have heart attacks and strokes; high levels appear to be protective. In the Framingham Heart Study, low levels of HDL were an even more potent risk factor for heart disease than high levels of LDL. Other studies have linked high HDL levels to a reduced risk of stroke, greater longevity, and better cognitive function in old age.
Luckily, there are things you can do to increase HDL, both in terms of medications to take and lifestyle changes to make. A later article in Focus On: Cholesterol will explore in detail the ways to increase HDL.
Just as important, a diet that is heavy in fruits, vegetables, beans, and nuts is good for the body in ways beyond lowering cholesterol. It keeps blood pressure in check. It helps arteries stay flexible and responsive. It’s good for bones, digestive health, vision, and even mental health. That’s a portfolio worth protecting.
In with the Good
The following 10 types of foods work in one or more of these ways to lower cholesterol: Oats such as oatmeal or cold, oat-based cereal like Cheerios; Barley and other whole grains; Beans; Eggplant and okra; Nuts; Vegetable oils such as canola, sunflower, and safflower; Apples, grapes, strawberries, citrus fruits; Foods fortified with sterols and stanols, which include foods ranging from margarine and granola bars to orange juice and chocolate; Soy, such as tofu or soy milk and fatty fish.
Out with the Bad
To improve your cholesterol level, the main things to cut from your diet are saturated fats (found in red meat, milk and other dairy foods, and coconut and palm oils which directly boost LDL) and trans fats which boost LDL as much as saturated fats do. They also lower protective HDL cholesterol, rev up inflammation, and increase the tendency for blood clots to form inside blood vessels. The Institute of Medicine recommends getting no more than two grams of trans fats a day; less is even better. Look on the label of packaged foods such as cookies and crackers to make sure they don’t have trans fats. Fried foods in restaurants can also contain them.