Preventive Medicine and NutritioN
Cholesterol and Heart Disease
Every day, more than 4,000 Americans suffer a heart attack. Those who survive often go on to have another one later on. But this need not happen. Eating habits and other parts of our lifestyle play a large role in the risk of heart disease. The good news is that heart disease can usually be prevented and even reversed.
Atherosclerosis is the all-too-common form of heart disease in which plaques of cholesterol and other substances, very much like small tumors, form in the artery walls. Eventually, the passageway for blood becomes clogged. Less blood flow means less oxygen for the heart muscle. Chest pain (angina) occurs, usually following exercise or excitement. When the blood supply is completely cut off, a part of the heart muscle dies—this is known as a heart attack.
Atherosclerosis is not caused by old age. When battlefield casualties were examined during the Korean and Vietnam wars, American soldiers had significant atherosclerosis at only 18 or 20 years of age. Their Asian counterparts, raised on a diet consisting mainly of rice and vegetables, had much healthier arteries.
The main reason that older people are more likely to have heart problems than younger people is that they have had more time to indulge in unhealthy habits. Similarly, most people do not have a hereditary tendency towards heart disease. In most cases the problem is not usually due to genetics, but to eating and smoking habits. Your doctor can tell you if you are 1 of only about 5 percent of the population with a true genetic tendency towards heart disease.
Many studies have shown the connection between cholesterol and heart problems. Beginning in 1949, under the direction of William Castelli, M.D., the population of Framingham, Massachusetts, has been monitored to see what influences the rate of heart disease.1
Castelli’s study has shown that there is a cholesterol level below which, essentially, heart attacks do not occur.
“We’ve never had a heart attack in Framingham in 35 years in anyone who had a cholesterol level under 150,” Castelli said. “Three-quarters of the people who live on the face of this Earth never have a heart attack. They live in Asia, Africa, and South America, and their cholesterols are all around 150.”
What Is Cholesterol?
Cholesterol is not the same as fat. If you had a bit of cholesterol on the end of your finger, it would look like wax.
The liver manufactures cholesterol and sends it out to be used in the manufacture of hormones and cell membranes, and in other parts of the body. Cholesterol levels are measured in milligrams (mg) of cholesterol per deciliter (dl) of blood serum. Based on the results of the Framingham Heart Study and other research, the ideal level appears to be below 150 mg/dl. At that point, a heart attack is very unlikely.
Unfortunately, the average cholesterol level in America is 205, which is not far from the average level for heart attack victims: 244. Surprisingly, the federal government’s recommended maximum level is still as high as 200.
Different Types of Cholesterol
When cholesterol is transported in the bloodstream, it is packed into low-density lipoproteins (LDL), sometimes called the “bad cholesterol.” Although it is necessary in limited quantities, a high LDL cholesterol level can dramatically increase your risk of a heart attack.
LDL delivers cholesterol to various parts of the body. When cholesterol is released from dead cells, it is picked up for disposal in another kind of package, called high-density lipoproteins (HDL), the “good cholesterol.”
When doctors measure cholesterol levels, they first look at total cholesterol as a good, quick guide to a person’s risk. For a more exact guide, they divide the total level by the HDL level. The lower your total cholesterol level, and the higher your HDL as a proportion of this, the lower your risk of a heart attack.
The ratio of total cholesterol to HDL should, ideally, be around 3 to 1. Unfortunately, the average American male’s ratio is much higher than that, at 5.1 to 1. Vegetarians, on the other hand, average only about 2.9 to 1.1
Smoking and obesity appear to lower HDL, but HDL can be raised somewhat by vigorous exercise and foods which are rich in vitamin C.2
How to Lower Your Cholesterol
Since our bodies make plenty of cholesterol for our needs, we do not need add any in our diet. Cholesterol is found in all foods that come from animals: red meat, poultry, fish, eggs, milk, cheese, yogurt, and every other meat and dairy product. They should be avoided. No foods from plants contain cholesterol.
People can therefore reduce their cholesterol levels dramatically by changing the foods they eat. And every time you reduce your cholesterol level by 1 percent, you reduce your risk of heart disease by 2 percent.3 For example, a reduction from 300 mg/dl to 200 mg/dl (i.e., a one-third reduction) will yield a two-thirds reduction in the risk of a heart attack. For some people, the benefits are even greater.
Every 100 mg of cholesterol in your daily diet adds roughly 5 points to your cholesterol level, although this varies from person to person. In practical terms, 100 mg of cholesterol is contained in four ounces of beef or chicken, half an egg, or three cups of milk. Beef and chicken have the same amount of cholesterol, 25 mg per ounce.4 Unlike fat, cholesterol is located mainly in the lean portion of meat.
Animal products also contain saturated fat, which causes the liver to produce more cholesterol. Unsaturated fats do not have this effect. Saturated fats are easy to spot because they are solid at room temperature, whereas unsaturated fats are liquid. Beef, chicken, and most other animal products contain substantial amounts of saturated fat. This is another good reason for avoiding such products.
Unfortunately, the food industry often presents the fat content of certain products in a misleading way. By reporting the fat content by weight, they are allowing the water content to throw off the measurements and make these products look more healthful than they actually are. The important piece of information is the percentage of calories from fat.
In the leanest cuts of beef, about 30 percent of the calories come from fat. Skinless chicken is nearly as high, at 23 percent. Even without the skin, chicken is never truly a low-fat food. Grains, beans, vegetables, and fruits, however, have comfortably less than 10 percent of their calories coming from fat.
Saturated Vegetable Oils
A few vegetable oils are also high in saturated fats. These are known as tropical oils: palm oil, palm kernel oil, and coconut oil. Hydrogenated oils are also high in saturated fat.
While liquid vegetable oils are much better than animal fats and tropical oils, all fats and oils are natural mixtures of saturated and unsaturated fats. Therefore, none of them will do your coronary arteries any good, and should be kept to a minimum.
While the saturated part of oil is what increases your cholesterol level, the unsaturated parts have health problems of their own. These include a tendency to increase free-radical production, impair the immune system, and increase body weight.
Blood pressure is also a risk factor for heart disease, and can lead to strokes and other serious health problems as well. Luckily, this is another area where we can take control by watching the foods we eat.
Salt has an effect on blood pressure, and should be kept to a minimum. But this is only the beginning. Numerous studies have shown that vegetarians have lower blood pressure than non-vegetarians. A low-fat, high-fiber vegetarian diet, even without lowering salt intake, can lower blood pressure by as much as 10 percent. The biological explanation for this has never been clear. Vegetarian diets are lower in fat and sodium, but there is a blood pressure-lowering effect beyond those two factors. An additional benefit is reduced iron storage in vegetarians. Studies have shown a strong link between iron and heart disease, and also between iron and hypertension.5
It is not much use having a healthful meal if it is followed by a cigarette. Other factors can have just as much of an impact on the heart as diet can.
People who smoke have a much higher risk of heart disease than non-smokers do. Moderation is not good enough—it is essential to quit.
Physical activity is also important. Regular light exercise, such as a daily half-hour walk, can cut death rates dramatically.
Finally, stress takes a toll on the heart. Daily life is full of events that cause our hearts to beat a bit faster and drive up our blood pressure.6Reducing stress means keeping your challenges within a range you can manage. Getting adequate rest and learning techniques for stress reduction, meditation, or yoga can be very helpful.
That being said, taking control of the other factors cannot undo the effects of a bad diet. The only way to a healthy heart is an all-encompassing healthy lifestyle which incorporates a varied, low-fat, vegetarian diet, daily physical activity, and stress reduction.
And Now the Good News: Reversing Heart Disease
On July 21, 1990, The Lancet published the findings of Dean Ornish, M.D., who demonstrated that heart disease can actually be reversed without medicines.7 Until then, most doctors were not even attempting to reverse heart disease, even though it was, as it is now, the most common cause of death. Most believed that the plaques of cholesterol and other substances that clog the arteries to the heart would not go away. The traditional way to remove them was to wait until they became severe enough to warrant a bypass or angioplasty.
At the University of California in San Francisco, Dr. Ornish tested the theory that a more potent diet, along with other lifestyle changes, might actually reverse heart disease. He selected patients who had plaques that were clearly visible on angiograms, and split the patients into two groups. Half were referred to a control group in which they received the standard care that doctors prescribe for heart patients. The other half began a vegetarian diet in which less than 10 percent of calories were contributed by fat. They were also asked to begin a program of modest exercise, and learned to manage stress through a variety of simple techniques. Of course, smoking was not permitted.
Dr. Ornish’s patients started to feel better almost immediately, and continued to improve over the course of the year. They had previously been struggling with the crushing chest pain of heart disease, but “most of them became essentially pain-free,” Dr. Ornish said, “even though they were doing more activities, going back to work, and doing things that they hadn’t been able to do, in some cases, for years.”
Not only did their cholesterol levels drop dramatically, but, after a year, 82 percent of the patients who followed Dr. Ornish’s program showed measurable reversal of their coronary artery blockages. The plaques were starting to dissolve with no medications, no surgery, and no side effects.
The control group, following the more traditional medical routine, did not do so well. For most patients, chest pain did not go away, but continued to get worse, and their plaques were continuing to grow, cutting off blood flow to the heart a bit more with every passing day.
The work of Dr. Ornish and others has made previous recommendations obsolete.
Many doctors still recommend “chicken and fish” diets, even though a number of studies have shown that, in general, heart patients who make such moderate dietary changes tend to get worse over time. Those who adopt a low-fat, vegetarian diet, get daily physical activity, avoid tobacco, and manage stress, stand the best chance of reversing heart disease.
We now have the most powerful tools yet for gaining control over the health of our hearts.
1. Castelli WP. Epidemiology of coronary heart disease. Am J Medicine 1984:76(2A):4-12.
2. Trout DL. Vitamin C and cardiovascular risk factors. Am J Clin Nutr 1991;53:322S-5S.
3. Lipid Research Clinics Program. The Lipid Research Clinic?s Coronary Primary Prevention Trial Results, II. JAMA 1984: 251(3):365-74.
4. Pennington JAT. Bowes and Church?s Food Values of Portions Commonly Used. New York: Harper and Row, 1989.
5. Salonen JT, Salonen R, Nyyssonen K, Korpela H. Iron sufficiency is associated with hypertension and excess risk of myocardial infarction: the Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD). Circulation 1992;85:759-64.
6. Schnall PL, Pieper C, Schwartz JE, et al. The relationship between ?job strain,? workplace diastolic blood pressure, and left ventricular mass index. JAMA 1990;263:1929-35.
7. Ornish D, Brown SE, Scherwitz LW, et al. Can lifestyle changes reverse coronary heart disease? Lancet 1990;336:129-33.
For more information on lowering cholesterol, and other benefits of a low-fat vegetarian diet, PCRM recommends: