Merely an obscure scientific term a few decades ago, cholesterol has quickly become a household word with an image that’s almost universally “bad.” If you associate cholesterol with excess weight, fried foods and an increased risk of suffering a heart attack or stroke - as most Americans do – you’re right! But that’s only one over-simplified part of a complex story.
Cholesterol is a naturally occurring wax-like substance needed by the body to build cell walls and make hormones. Without cholesterol that work would never get done. However, the body is capable of producing every bit of cholesterol that’s needed.
“Cholesterol will circulate in your blood regardless of what you do, but levels are sometimes increased by lifestyle measures, such as a diet that’s high in the wrong kind of fats,” says Coeta Ogle, RN, BSN, at St. John’s Regional Medical Center in Joplin, MO. Over an extended period too much cholesterol in the blood stream can lead to fatty deposits on the walls of arteries, known as atherosclerosis or hardening of the arteries. These deposits in turn hinder blood flow, causing high blood pressure and other health problems, including a heart attack or stroke.
“That’s why, as routine, preventive practice, doctors frequently ask patients to get a blood test measuring cholesterol and other lipids (or fats) in the blood. Known as a lipid profile, this test renders valuable information about an individual’s risk of heart disease,” adds Ogle.
If you’re like most Americans, what you remember about your cholesterol is probably a three-digit number – your total cholesterol. “It’s a handy number to keep in mind because it says a lot.” Ogle adds, “if your total cholesterol is under 150, you’re doing great: if it creeps over 200, you should start being concerned; and if it’s over 239, your doctor has probably talked to you about things you should do, including the use of cholesterol-lowering medications.”
Total cholesterol is a rough measure of what’s taking place in your blood vessels, but, in interpreting the results, your doctor is more concerned about other components of the profile. Two of these components, known as “good” and “bad” cholesterol, are lipoproteins – special proteins that act as couriers in the blood stream, delivering cholesterol to wherever it’s needed.
As an analogy, think of HDL (high density lipoproteins) as highly fit bike riders, powering themselves efficiently through the blood stream. LDL (low density lipoproteins) on the other hand, are loosely formed blobs that float like sponge toys on the surface of the bathtub. LDL is “bad” cholesterol because it tends to collect, making fatty deposits that block the normal flow of blood through the arteries. HDL is “good” because it gathers up excess LDL particles and carries them back to the liver to be removed from the body as waste. If your HDL cholesterol is high, as it should be, your LDL and total cholesterol are likely to be low.
According to guidelines of the National Cholesterol Education Project (NCEP), an HDL level above 60 mg/dL is desirable and considered protective against heart disease. A level under 40 mg/dL, on the other hand, is a risk factor, even if other components of the profile are normal.
For most individuals, an LDL under 130 is recommended, but persons diagnosed with heart disease or diabetes are advised to keep their LDL under 100 mg/dL. One of the most important measures of cardiovascular health is the ratio of total cholesterol to HDL ratio. The NCEP recommends a ratio under 4.5.
Another fat usually measured in a lipid profile is triglyceride. A high triglyceride level, frequently caused by excess weight and high intake of fat, alcohol and sweets, usually occurs in conjunction with low levels of HDL cholesterol. Triglyceride levels under 150 mg/dL are considered desirable, and recent research indicates that high triglycerides are a risk factor even when other parts of the lipid profile are normal.
Most preventive and treatment strategies focus on lowering LDL and total cholesterol. Yet studies show that increasing HDL – even with no corresponding decrease in LDL – may be at least as effective in reducing the risk of heart attack and stroke. “While a traditional low-fat diet will lower LDL and total cholesterol, it may also lower HDL, particularly if carbohydrates are substituted for the fats. More recent approaches advocate not just eliminating saturated fats but replacing them with fruits, vegetables, whole grains and monounsaturated fats. Found in olive and canola oil, almonds, walnuts and avocados, monounsaturated fats will maintain or increase HDL levels while providing beneficial antioxidants and nutrients,” adds Ogle.
Probably the best two ways to boost HDL are 1) weight loss and 2) regular exercise of at least moderate intensity. Other strategies to increase HDL include smoking cessation, avoidance of trans fatty acids (found in many margarines and baked goods) and moderate use of alcohol. Studies have shown that individuals who have one to two alcoholic drinks a day have HDL levels 12 percent higher on average than non-drinkers. Among cholesterol lowering medications, statins bring about a 10 to 15 percent increase in HDL while reducing LDL by 30 to 50 percent. Niacin may be the best treatment for increasing HDL, and fibrates are the treatment of choice for high triglycerides.
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