I’m sure you’ve heard the phrase, “You are what you eat”, and chewing the fat clearly impacts the cholesterol and triglyceride levels of most people. In the last twenty years, especially, people have become better educated about their cholesterol levels and the health impact of such levels. However, in my practice, I see people often knowing just enough to be confused, or even a little dangerous in their well-meaning attempts to educate others. I am hopeful that after reading this insight, you will understand how fats and cholesterol affect our health.
Cholesterol is a fat-like waxy substance which is derived from certain foods but is also produced naturally by the liver. It is carried through the bloodstream and has important roles as a building block of cellular membranes, is a component of various hormones, and is critical in the production of Vitamin D.(The Wellness Book, 1992). So, contrary to what many people believe, cholesterol is not all bad. However, an elevated cholesterol level is a major risk factor for the development of cardiovascular disease because it is a major component in the build up of deposits on the walls of blood vessels. The technical term for this build-up is atherosclerosis or atherosclerotic plaque. But there are three components of cholesterol that are very different, and they each need to be understood to see the big picture.
Total cholesterol, HDL-cholesterol, and LDL-cholesterol are these three components. Substances called lipoproteins actually carry the cholesterol through the bloodstream. HDL-cholesterol (or high density lipoprotein cholesterol) is often called GOOD cholesterol. Cholesterol carried through the bloodstream by HDL is transported to the liver and subsequently enters the intestines for elimination from the body. So, in fact, HDL-cholesterol actually carries cholesterol AWAY from the blood vessels, and higher levels of HDL-cholesterol actually help to protect us from heart disease. In contrast, the LDL-cholesterol (low density lipoprotein cholesterol) can be deposited on the blood vessel walls and is often referred to as BAD cholesterol. The deposition of LDL-cholesterol to blood vessel walls serves to narrow the channels of blood overtime; and may ultimately lead to complete blockages of blood vessels if not stopped or reversed.
Now that you understand the types of cholesterol, what do the NUMBERS actually mean? In general, a total cholesterol of 200 or less is considered desirable, and total cholesterol levels of 240 or higher are too high. HDL-cholesterol levels less than 35 are considered undesirable or too low, and you can’t be too high in this value on the good side. Remember, HDL carries cholesterol OUT of the bloodstream. . .so the more the merrier. I occasionally see elderly women in my practice with HDL cholesterols over 100. No wonder they have made it to age 90 without heart disease! An LDL-cholesterol under 130 is considered a desirable level for most people, although diabetics and people with documented heart disease should maintain LDL-cholesterols of 100 or less to reduce the risk further. LDL-cholesterol levels of 130-150 are considered borderline high, and LDL cholesterols of 160 or greater are too high. Remember, however, that cholesterol levels are just a part of the whole heart disease risk picture. If a person has normal blood pressure, does not smoke, is not diabetic or overweight, exercises regularly and has no relatives with significant heart disease, an LDL-cholesterol level of 160 is generally not a serious problem. For a sedentary, overweight 46 year old smoking man who also has high blood pressure and a father with heart disease, even an LDL cholesterol of 110 may be too high. And remember, such a hypothetical patient has the ability to decrease 5 of the above 8 risk factors through will power and use of medication–he’s stuck with his sex, his age, and his family history.
Okay, you now understand cholesterol. What about triglycerides? Triglycerides are blood fats that carry energy to various parts of the body and are generated by breakdown of foods we eat. As a consequence, the triglyceride levels in our bloodstream vary tremendously throughout the day. . .based on our eating patterns. Until recently, a fasting triglyceride level of 200 was considered healthy. However, research has now shown that people with fasting triglyceride levels of 100 and higher have twice the risk of heart attack and twice the risk of needing heart surgery when compared to people with fasting triglyceride levels below 100. So, triglyceride levels are important in the risk equation as well. The good news is that triglycerides are much more responsive than blood cholesterol to simple lifestyle changes which include: low-fat eating, fewer sweets, less alcohol, and regular exercise. These changes alone can reduce triglyceride levels up to 40%.
So our diets clearly influence our cholesterol and triglyceride levels. Unfortunately, so does heredity. The body’s overproduction of cholesterol is the main reason some people have high LDL-cholesterol levels. Heredity also clearly affects the HDL-cholesterol levels. . .and some people cannot generate desirably high HDL-cholesterol levels no matter how hard they try with exercise and lifestyle. The task in such folks is to do what they can to reduce the other risk factors for heart disease. . .thereby making the low HDL level less important in their overall heart disease risk. And, some of our cholesterol lowering drugs can have a moderate impact in raising the HDL level. We also know that stress hormones (specifically adrenalin) can increase the amount of cholesterol produced by the body. Studies on medical students (a captive audience) showed that their cholesterol levels increased an average of 25% when measured during final exams. Studies have also demonstrated that patients with high cholesterol levels who learn and practice efficient relaxation techniques can effect a meaningful drop in cholesterol levels during the course of a year.
If lifestyle changes alone do not bring cholesterol levels into the desirable range, there are very effective drugs available as adjunctive therapy. For the most part, these drugs are safe with few side effects, but your physician will need to monitor you periodically with blood tests to follow their benefit and to check for any abnormalities in your liver and muscle enzyme tests. Drugs are now also available to help lower triglyceride levels. I am not going to discuss specific eating patterns here, but do remember that the bulk of our dietary cholesterol comes from animal sources. . .including dairy products. Chewing the fat is a tasty way to eat, but there can be negative health consequences. See your physician and have your cholesterol and triglyceride levels checked periodically. You can’t “feel” them rising, but the longterm consequences of elevated levels can be deadly.
Stephen L. Hines, M.D.
April 2000
