High-Density Lipoproteins

High-density lipoproteins (HDLs) are often referred to as the “good” cholesterol. HDL is cholesterol packaged in a coat of protein and phospholipid. HDL carries approximately one-third of blood cholesterol. HDL protects arteries by harvesting cholesterol from the arterial walls and the blood. It brings the scavenged low density lipoproteins (LDLs) back to the liver where it is converted to bile and excreted. HDL counteracts the accumulation and growth of plaque from Low Density Lipoproteins (LDL), also known as the “bad or lousy cholesterol. A higher HDL level is equated with the body operating at optimal capacity. Low levels of HDL may be linked to a higher risk of coronary heart disease (CHD). Opposite trends are seen between LDL and risk for cardiovascular problems, including coronary heart disease.

Dietary change appears to influence cholesterol levels. Monounsaturated fats and polyunsaturated fats are healthier alternatives to saturated fats and trans-fats. Monounsaturated fats include olive oil, canola oil, avocadoes, and most nuts. Polyunsaturated fats include the oils of seeds and grains including safflower oil, corn oil, sunflower oil, walnut oil, and soybean. In determining cholesterol levels, the type of fats included in the diet are critical. Saturated and trans fats tend to raise LDL cholesterol levels, while at the same time, these fats do not show beneficial effects on HDL levels. In contrast, fatty fish provides a source of omega-3 fatty acids which may help to raise HDL. Examples of good sources of omega-3 fatty acids include mackerel, herring, sardines, anchovies, and salmon.

It is desirable for HDL to be 60 milligrams of cholesterol per deciliter of blood (mg/dl) or higher. HDL less than 40 mg/dl is considered to be low and raises the risk of CHD.

Lifestyle factors appear to have the most significant influence on HDL levels. Obesity, smoking, and inactivity may lower HDL. Genetics may play a role in determining total cholesterol levels as well. Further, the presence of type 2 Diabetes Mellitus also tends to be related to lower levels of HDL cholesterol (although factors such as the existence of obesity and related conditions may confound this relationship). Exercise and weight loss key lifestyle factors that can contribute to more favorable blood cholesterol levels (higher HDL, and lower LDL). Furthermore, quitting smoking may raise HDL and decrease the tendency of the blood to form clots. There is no medication specifically designed to raise HDL. Some medications designed to lower LDL may raise HDL. Lifestyle changes appear to exhibit the most significant positive impact on raising HDL.