Cholesterol! The word strikes fear into the hearts of many Americans. Popular press and TV have dumbed down the basics of cholesterol:

• High total cholesterol is associated with heart attack and stroke.
• LDL (low density lipoprotein) Cholesterol is bad.
• HDL (high density lipoprotein) Cholesterol is good.

Healthy Cholesterol Levles Aren't Quite That Simple

There is in fact only one kind of cholesterol. Whether obtained from the diet or synthesized by the liver, it is immediately bound to specific carrier substances, lipoproteins, and transported via the blood stream to the 60 trillion cells of the body. LDL is the major lipoprotein responsible for the transport of cholesterol TO the cells of the body. HDL, in contrast, takes cholesterol FROM the cells of the body and transports it back to the liver, where it is sequestered, or metabolized and secreted in the intestine as bile.

Our bodies require a certain amount of cholesterol for numerous cellular functions, including cell membrane integrity, absorption of nutrients such as fat-soluble vitamins, and synthesis of vitamin D and sex hormones. Too much of it can hurt us, however. Research has demonstrated an association between elevated LDL and atherosclerosis, a disease of the arteries causing heart attack and stroke.

How does this work? When the LDL-cholesterol combination (technically, LDLc) is present in the blood at a high level, it diffuses across the endothelial cells that line the interiors of blood vessels and is deposited just underneath these cells. This leaves a pool of LDL within the wall of the blood vessel. LDL is susceptible to attack by common cellular oxidants, which in effect turn it rancid. When LDL is present in the blood at normal healthy amounts, this does not occur, as there are substances, such as HDL and cellular antioxidants, to protect it from oxidation.

When the blood level of LDL Cholesterol is too high, large amounts of LDL transfer across the vessel wall, the antioxidant protection is overwhelmed, and LDL is oxidized (turns rancid). Now it becomes toxic to the cell and surrounding tissue. The process is aggravated by hypertension (high blood pressure), a condition characterized by elevated vascular pressure that can excessively stretch vessels and stimulate the oxidation of LDL.

Since the liver has the capacity to make cholesterol, we really don't need much of it from the foods we eat. In general, western industrialized man has too much LDL, largely as a result of sedentary lifestyles, and a diet high in substances that promote cholesterol synthesis, such as saturated fat, and trans fats. More than 90 million American adults - about 50% - have unhealthy blood-cholesterol levels.

What can you do to avoid being one of them? Recently, new standards have been suggested for the desired level of HDL (>40mg/deciliter), LDL (<100mg/dl) and total cholesterol (<200 mg/dl). As we age, these figures go in the wrong direction. Total cholesterol and LDL go up; HDL goes down. Most people can correct these markers of health to optimal or near optimal levels with minimum effort and cost. This is one area of healthcare that has real solutions. Various approaches are available to either control these precursors of poor health or help maintain levels that are already within the normal range.

Diet and Lifestyle. Diet does have an effect, but the intensity of it varies with age, genetic constitution and physical condition. The diet should include about 25-30% of total calories from fat. Less than 10% of these calories should come from saturated fats (which raise LDL), and none from trans fats (which raise LDL and lower HDL). A diet high in fruits and vegetables (7 servings/day), nuts and fiber has been demonstrated to promote a healthy lipid profile.

Lowering total cholesterol by diet and keeping your total daily intake of cholesterol to less than 300mg/day almost always improves the ratio of HDL/LDL. It stimulates the synthesis of LDL receptors in liver cells, thus decreasing the circulating level of the lousy cholesterol. Avoiding a sedentary lifestyle and maintaining a regular exercise routine can significantly improve the level of HDL.

Drugs. OK, you did all that and your cholesterol level, although improved, remains in the red zone, so now what? Numerous ads on TV and elsewhere promote cholesterol-lowering prescription drugs, but many of us are aware of documented side effects from these drugs. On the other hand these drugs, commonly referred to as statin drugs, do work. They lower cholesterol by as much as 45-50% and raise HDL, while lowering LDL and another circulating neutral fat, triglyceride. The bottom line is they have been shown to work, and they decrease mortality from atherosclerosis.

Supplements. Dietary supplements can help improve and or maintain cholesterol levels. One example is a plant-derived substance commonly known as policosanol. Niacin (vitamin B3), in large doses (>1gm/day), has a significant effect on lowering triglycerides, and raising HDL, especially when used in combination with one of the statin drugs or policosanol. Any decision to try these dietary supplements should be taken under a health professional’s supervision, since these products, like the statin drugs, may have side effects.

Another approach to help maintain cholesterol levels that are already within the normal range is to supplement with antioxidants, since the body's natural inflammation response involves oxidants. The potent antioxidant alpha lipoic acid may help by acting directly to neutralize oxidants and indirectly by increasing levels of two key antioxidants, vitamin C and glutathione, in the cells lining the vessel walls. Lipoic acid also enhances synthesis of the chemical messenger, nitric oxide, which in turn protects the function of these cells and promotes vascular relaxation.

Whichever approach you choose, the important thing for healthy aging is to get your cholesterol under control and keep it there.

This month we highlight once again a study of the powerful antioxidant alpha lipoic acid. Among the general population, double-blind, placebo-controlled clinical trials, with human subjects, are perhaps the most widely known form of healthcare testing. Studies in laboratory animals are even more extensively used by pre-clinical scientists. To understand fundamental biochemistry, however, scientists often use cell cultures.

S cientists at Vanderbilt University School of Medicine examined the antioxidant effects of alpha lipoic acid in cultured human endothelial cells (which line our blood vessels). They found that alpha lipoic acid enhances both the antioxidant defenses and the function of endothelial cells. For details on how alpha lipoic acid protects the cells lining the arteries to prevent inflammation, click here.

This Research Update column highlights articles related to recent scientific inquiry into the process of human aging. It is not intended to promote any specific ingredient, regimen, or use and should not be construed as evidence of the safety, effectiveness, or intended uses of the Juvenon product. The Juvenon label should be consulted for intended uses and appropriate directions for use of the product.