Cholesterol and Coronory Heart Disease

V. Vemuri

The Swinging Pendulum

Popular opinion swings like a pendulum. From dawn to dusk you are bombarded with contradicting expert opinions, analysis of the expert opinion by other experts, and interpretations -- for popular consumption -- of the analyses by newscasters. Somewhere along the way, the facts are lost.

Public conciousness about cholesterol was first aroused in 1987. Newspapers, magazines, talkshows, television commentaries - you name the place, they got you there. Do-it-yourself cholesterol screening centers began to pop out of the pavements. Two years later, Random House published a headline-grabbing book, Heart Failure, by Arthur J. Moore. It asserted that the cholesterol scare was a product of poor research, inaccurate and incomplete laboratory testing, and unethical schemes by money-hungry pharmaceutical companies. On the heels of this book came a warning, from the Department of Health and Human Services, that most tests and screening procedures were sloppy at best and unreliable at worst.

What is Cholesterol?

The most informed answer to the cholesterol controversy can be found by learning more about it. Let us start with lipids, a generic term used by scientists to describe both fats and oils. In a nutshell, fats are solid lipids and oils are liquid lipids. The liquid portion of our body, such as blood and other body fluids, is made up of an aqueous phase and a lipid phase . The aqueous phase contains not only water but also substances which are soluble in water, such as sugar, some proteins, and so on. The lipid phase contains not only fat, but also substances which are soluble in fat, such as steroids and certain vitamins. Although oil and water do not mix, an intricate and delicate chain of chemical reactions forces these two phases to coexist in our bodies.

An important lipid phase material is cholesterol, a waxy substance produced by our bodies. There is more than 200 grams of cholesterol in our body. A small part of this is used as a raw material for the formation of hormones. A major part of this is found in cell membranes and, in particular, in the fatty sheaths that surround nerve fibers. In fact, the dry matter of the brain (that is, ignoring the water content) is one-fifth cholesterol. Obviously, cholesterol is important stuff and it is needed everywhere. It is important enough for the blood stream to be dragging it hither and thither.

How does this waxy stuff get transported by the blood? It is sort of held in suspension in the lipo-proteins of blood plasma ; somewhat like the way butter is suspended in milk. As the blood stream careens on its way through the arteries, some of this material "spills off" as butter would if you shake milk. Once it spills off, the aqueous phase plasma cannot drag it along and the cholesterol settles instead on the inner membranes of the blood vessels. This happens, generally, in the arteries because the blood flow there is both swift and turbulent and it is easier for the suspended cholesterol to spill off.

This process begins by age 20. By age 40, the build up of the stuff in the arterial walls is accelerated if the person smokes or has high blood pressure. Once, cholesterol begins clogging up the inner surface of an artery, it narrows the bore. This condition is called atherosclerosis or arteriosclerosis. .The deposits reduce the elasticity of the arterial wall. Gradually, the internal surface of the vessel becomes rough and ragged, offering opportunities for blood to pool behind eddies and clot. These clots may eventually block the flow of blood in some vessels. This condition is called thrombosis . When thrombosis occurs in an artery that carries blood supply to the heart muscle itself, the result is what is commonly known as "heart attack." In the small arteries of the brain, a clogged vessel results in "paralytic stroke." Either way, life is in danger.

Remember, our bodies need cholesterol to produce bile acids, hormones, and some cell structures. To meet these needs the body manufactures most of its own cholesterol. But some also enters the body via the food, derived from non-vegetable sources, we eat. Whatever way it gains a foothold in the body, eventually some of it enters the blood stream. Over a period of time cholesterol deposits accumulate on the arterial walls. While scientists are still debating about the true mechanism of arteriosclerosis, some believe that a defect in the body chemistry causes the accumulation of fatty acids, the main component of fats and oils. These fatty acids, in turn, are believed to be the raw material in the manufacture of cholesterol. Roughly two-thirds of the cholesterol found in the body is manufactured from these fatty acids.

Controlling Cholesterol Through Diet

Although the final verdict is not yet out, as a precaution, doctors say that we should try to keep the cholesterol level in our blood low. This can be done by avoiding the consumption of cholesterol containing foods. Because cholesterol is an animal product, not a product of the vegetable kingdom, this would entail, first, a reduction in the consumption of animal fats. Which animal fats? The most often cited culprits are the yellow part of eggs; butter fats such as those associated with butter, whole milk, cream, ice cream and cheese; fats associated with meats; and meats associated with brain and liver. While eating chicken, skin - which is 50% fat - should be avoided. Reduction of fat consumption not only helps in putting a lid on cholesterol production, but it also helps in controlling obesity and body weight; ounce for ounce, fat is packed with more than twice as many calories as carbohydrate or proteins. In any event, many experts believe that excessive fats (animal as well as vegetable) are the single most important cause of disease in the U. S.

A rule of thumb is to minimize from diet all fats that have a tendency to solidify at room temperature, because these fats contain the so-called saturated (saturated with hydrogen, that is) fatty acids, and they are believed to be one of the prime factors that influence the production of cholesterol. This suggests that red meats like beef, pork, and lamb head the list of foods to be avoided; poultry and fish are alright. Butter and butter derivatives occupy the next place in the infamous list. Apart from the animal fats, the most often cited culprits from the vegetable kingdom are the saturated fatty acids in palm oil and coconut oil; in fact these are 90% saturated compared to beef fat's 40%. Many processed foods, including non-dairy milk substitutes, contain these oils. So read the labels.

Oils with mono-unsaturated fatty acids, such as olive, peanut, almond, and avocado oils and those with poly-unsaturated fatty acids, such as Omega-6 (found in corn, sesame (til), safflower, sunflower and soybean oils are much better. What about margarines (vanaspatis) and shortenings? To answer this question, we have to understand that "saturation" refers to the amount of hydrogen in an oil's fatty acids. An unsaturated fatty acid can "take in" some more hydrogen atoms to become saturated. Margarine manufacturers take some inexpensive unsaturated oils and force hydrogen into them, a process called hydrogenation, until they become partially saturated. They do this because the solidified oils are easy to handle and can be stored longer. Also, during hydrogenation some oils lose any unpleasant odor they may have. In some countries, manufacturers use even deodorized fish oil or beef tallow as the raw material. Vegetarians, beware! Depending on the degree of saturation, which varies from 5% to 60%, the margarine will be soft or hard. If naturally occurring saturated oils like coconut oil are bad, what can we say about inherently inferior oils that are artificially saturated? You be the judge. What about fish oils belonging to the Omega-3 category? Fish is supposed to be good if consumed as a diet, but fads like Omega-3 oil capsules will do more harm than good if not used under the supervision of a physician; their dosage could turn out to be toxic.

Other Blood Fats

Lately, it is being realized that cholesterol is not the sole culprit in the coronory disease controversy. Blame is also laid at the door of a type of blood fats, called triglycerides. Many people with normal levels of cholesterol, and high levels of trigycerides, could wrongly receive a clean bill of health unless their doctor is aware of the implication of triglycerides. The anecdotal evidence I have indicates that many Indians have higher than normal levels of triglycerides normally found in the general Americal population.

Fake Fats

What about fake fats? Sucrose polyester, also called Olestra by Procter & Gamble, is made from sugar and edible oils. This has the same taste and cooking properties as regular fats and oils but has no calories and no cholesterol. The trick is to make the molecules so large that they go through the digestive tract unchanged. Developed first in 1968, this recently received approval from the Food and Drug Administration. Another synthetic fat, developed by NutraSweet Co. in 1979, goes by the name Simplesse. This fat-like compound, made from the proteins of milk and eggs by a process known as microparticulation, has about one calorie per gram and has no cholesterol. Regular fats have nine calories per gram. Simplesse cannot be used in frying or cooking because the heat would destroy the microparticles. How safe are these? We do not know, as yet. Are there any side effects? Well, people allergic to milk and eggs will be allergic to Simplesse. Too much of Olestra may interfere with the absorption of fat-soluble vitamins; the body does need fat, but not too much of it.

Role of Fiber and Complex Carbohydrates

It is widely accepted that fiber found in fruits, vegetables, cereals and grains is good for you in your battle with cholesterol. Fiber not only binds water thus promoting regularity, but it also helps indirectly. Many foods containing fiber also contain pectin, which binds to calcium in the body to form calcium pectate. This calcium pectate then combines with bile acids produced in the body, and makes the acids unavailable to do their duty in digesting dietary fat. The digestive system senses that there is a shortage of bile acid and goes to work. It extracts the cholesterol molecules from the blood and converts them into bile molecules. That is how, one theory says, fiber helps in reducing cholesterol in blood. That's why it is especially important for meat-eaters to make sure they have their regular dose of vegetables. Beans like pinto, kidney, and navy; psyllium, a seed grain; oat and rice bran; unmilled and unpolished rice; and fruits are all good sources of soluble fiber. According to a Department of Agriculture report, a cup of cooked rice, with its complex carbohydrates and only 200 calories, is also good in combating cholesterols and fats. When it comes to food, a word of wisdom is, "try a wide variety of foods, but always eat in moderation."

What is the Verdict?

Not all cholesterols, according to experts (here they come, again!), are bad. HDL (high-density lipoprotein) cholesterols are good. Needless to emphasize that LDL cholesterols are bad for you. But, you cannot have too much of a good thing either. You need a balance. Men tend to have naturally lower levels of "good" cholesterol and, as a group, are at a higher risk for coronary heart disease. Exercise has been shown to improve the level of "good" cholesterol.

Is cholesterol a problem of the affluent countries? Should Indians worry about this? Coronory heart disease knows no national prejudices. Aside from heriditary predisposition, the best established risk factors are elevated serum cholesterol levels, cigarette smoking, life style, high blood pressure, diabetes and obesity-- in that order. Two of these risk factors are completely in our control. If you stop smoking cigarettes and make some modest changes in life style your chances of encountering a fatal heart attack are substantially reduced. Life style factors contributing to coronory disease include stress, sedentary living, and a "sense of isolation." Stress brings on a rise in blood pressure and spurs the release of catecholamines, substances that increase the tendency of blood to clot. Researchers found that a 15 minutes a day of yoga and meditation is an effective way to counteract the ill effects of the first two factors. The only reasonable way to inculcate a sense of "togetherness" is for people to have close and supportive family relationships. In the long run it would be cheaper than paying -- in terms of money, time, and emotional upheaval -- for the cost of treatment.

What to do Post Facto?

Prevention, of course, is better than trying to reverse the damage done. What if it is too late to take preventative measures? There are two options. In fairly advanced cases, when the walls of arteries carrying blood to the heart muscle itself are blocked, coronory by-pass surgery is one recourse. In less urgent cases a patient can undergo angioplasty. In this procedure, the doctor inserts, under local anesthesia, a baloon-tipped catheter into an artery and guides it until the tip reaches the clogged region. Then the balloon is inflated to widen the arterial passages. In the United States, the price tag for a by-pass surgery hovers around $40, 000. For angioplasty the fee is the comparitively modest $8,000. These staggering prices, if not any thing else, are motive enough to prompt people to believe in an ounce of prevention.

(Appeared in Science Reporter, January 1994)