A waxy substance found in all of the body’s cells. The body uses cholesterol for a number of important functions, such as manufacturing certain hormones. As most people know, however, too much cholesterol in the blood can be damaging to the heart and blood vessels.
The liver manufactures most of the body’s cholesterol, but we also get it directly from the foods we eat. Cholesterol travels through the bloodstream in the form of complex molecules called lipoproteins. There are several varieties of lipoproteins, including low-density lipoproteins (LDL’s) and high-density lipoproteins (HDL’s).
LDL cholesterol, nicknamed the “bad” cholesterol, tends to mix with other substances in the blood and form buildups called plaques on the inner walls of blood vessels. These blood vessels can become hard and narrowed, decreasing blood flow, a condition known as atherosclerosis.
Plaques can also break off, form clots, and block key blood vessels, causing heart attacks and strokes.
HDL’s carry cholesterol away from the arteries to the liver, where it can be removed from the body. This keeps cholesterol from building up inside blood vessels, earning HDL cholesterol the nickname “good” cholesterol.
Doctors use the levels of HDL and LDL cholesterol to help determine a person’s risk of heart disease. The more LDL cholesterol and less HDL cholesterol a person has, the greater his risk of developing heart disease.
According to the cholesterol guidelines of the American Diabetes Association (ADA), adults with diabetes who have LDL cholesterol levels of 130 mg/dl or greater are at high risk of heart disease, those with levels of 100-129 mg/dl are at borderline risk, and those with levels below 100 mg/dl are at low risk. Men with HDL cholesterol levels under 35 mg/dl are at high risk, those with levels of 35-45 mg/dl are at borderline risk, and those with levels over 45 mg/dl are at low risk. Women with HDL levels under 45 mg/dl are at high risk, those with levels of 45-55 mg/dl are at borderline risk, and those with levels greater than 55 mg/dl are at low risk.
Even small improvements in blood cholesterol levels have been shown to significantly lower a person’s risk of heart attack. One way to lower your LDL cholesterol and raise your HDL cholesterol is through diet. For example, the ADA recommends consuming no more than 300 milligrams of cholesterol per day, and under 200 milligrams if you have high LDL cholesterol levels. (Foods high in dietary cholesterol include eggs, shellfish, and organ meats such as liver.) The amount of fat you eat, especially saturated fat, also affects your cholesterol level, so the ADA and other health organizations recommend getting no more than 30% of your daily calories from fat and limiting saturated fat intake to 10% or less of your daily calories. In fact, most of a person’s fat intake should come from monounsaturated and polyunsaturated fats. To achieve these goals, the best diet is one that emphasizes fruits, vegetables (including beans and other legumes), and whole grains.
Regular aerobic exercise, at least three to four times a week, can also improve blood cholesterol levels, especially when performed in conjunction with a low-fat diet. Walking briskly and jogging are good aerobic exercises. Losing weight if you’re overweight and stopping smoking may also help by raising your HDL cholesterol levels. There are also a number of highly effective drugs for improving cholesterol levels.
Everyone with diabetes should have their blood cholesterol levels checked regularly. Speak with your doctor and dietitian about ways to improve your blood cholesterol levels and reduce your risk of heart disease.