Cardiology: Four Fats in the Blood: Which Cause Heart Attacks?

Every week for the past year, more than 1,100 couples in five U.S. cities have selected a seven-day supply of food from a carefully drawn list and then sent their orders to Washington. Processed by a computer, the orders go back to shipping offices in the five cities, and the food is delivered. Container labels give no clue to the precise ingredients in such items as salad dressings, cake mixes and milk concentrates.

The computerized menus represent no attempt to automate a housewife’s traditional chore. They are part of a serious and important study, financed by the U.S. Public Health Service, designed to discover whether American men still in their prime can be saved from fatal heart attacks by changes in their diet.

The computer’s coldly calculated answers promise to help cut through the growing confusion about fats and the heart. Today, almost every time some authority sounds off on the subject, the effect is to multiply the contradictions. Last week the American Heart Association suggested that although the proof is not yet conclusive, the weight of evidence indicates that a lower-fat diet, with proportionately more polyunsaturated:|: vegetable fats, will help to save lives. But the Food and Drug Administration had just threatened action against manufacturers who label shortenings and cooking oils as polyunsaturated, thus implying that they are good for the heart and arteries.

Easy to Measure. Atherosclerosis that narrows or closes the heart’s coronary arteries with slushy, fatty deposits is the greatest killer in the U.S., where it claims 500,000 lives a year, twice as many as cancer. The death rate from prime-of-life heart attacks goes up, roughly, with the concentration of fats in the blood. Most biochem ists divide these circulating fatty substances into four groups: cholesterol, fatty acids, phospholipids, and triglycerides, some of them “free,” some of them combined with proteins or with one another.

It is not yet certain which of them are the most important in causing atherosclerosis. But cholesterol has received the widest publicity, largely because it is the easiest to measure and thus be comes a handy guide to arterial and coronary health. Among peasants in India, starved of protein and of fat, a cholesterol level of 125 milligrams per 100 milliliters of blood is common. It is about the same for fish-and-rice-eating Japanese. Among Americans living high off the hog, it hits 250 before a doctor begins to worry. And among men with coronary-artery disease, it may go to 500 or more.

The squishy, fatty nature of the deposits in clogged arteries has been recognized for more than 200 years, and the presence of cholesterol (from the Greek for bile solids) in the deposits has been known for more than a century. Presumably the cholesterol is deposited from the blood. Just how or why, no one knows. But high levels of circulating cholesterol go with a high incidence of heart attacks in men 45 to 65; doctors have spent years trying to figure out why the cholesterol piles up.

Animal v. Vegetable. The simplest explanation would be that the cholesterol comes from food. Eggs are a common source: their yolks are packed with the stuff. So are some meats. But the obvious explanation is only part of the truth. The high-blood-cholesterol man does not derive his cholesterol entirely or even mainly from his food. He manufactures most of it himself. And fat, it was found, is a prime raw material for his liver and other organs to use in making cholesterol.

This discovery soon proved to be another oversimplification. Most vegetable fats and oils cause little or no rise in blood cholesterol. So the line was drawn between animal and vegetable fats. But even that line was uncertain; it had to weave around to leave hard or saturated fats on one side and polyunsaturated fats on the other. The blubber of whales and the oil of seals and other marine mammals is polyunsaturated, so Eskimos can eat them and still keep their cholesterol low. Also polyunsaturated are the oils of fish. The fat of chickens and turkeys (unlike that of ducks and geese) is mainly neutral.

Richest of all in polyunsaturates are vegetable oils from corn, cottonseed, safflower, soybeans, and (if not artificially hydrogenated) peanuts and some olives. Virtually all contain fats with different degrees of saturation. What is important, say many heart-disease doctors, is the proportion of polyunsaturated to saturated.

Prudent Diet. Until 50 years ago, Americans consumed on the average only about 25% of their calories in the form of fat. They also got a great deal of physical exercise, which tends to keep fat from piling up either on the ribs or in the blood. By 1950, though, New York City’s late Dr. Norman Jolliffe estimated that fats made up at least 40% of the average American’s calories, and nearly all of them were hard, saturated fats.

Dr. Jolliffe started the Anti-Coronary Club, with 700 men aged 40 to 59 pledged to cut their fats to 30% or less of total calories, to trim off all visible fat from meats such as beef and lamb, and to use whole milk, butter, pastries, cheese and creamy desserts only as treats on special occasions. After seven years, there is no doubt that Anti-Coronary members have lower blood-cholesterol levels than before, and evidence is piling up that they have won considerable immunity to heart attacks.*

It was all very well to get 700 highly motivated men in New York City to goon Dr. Jolliffe’s “prudent diet,” but could the mass of American men be induced to do the same while still apparently healthy? Now the National Diet-Heart Study, headed by Cleveland’s Dr. Irvine H. Page (TIME Cover, Oct. 31, 1955), is seeking an answer. Backed by the U.S. Public Health Service, the study aims to find out 1) whether men will voluntarily restrict their diets now for the sake of a possible health gain in the future, 2) whether the prescribed diets will effectively lower blood cholesterol, and 3) if so, which of several diets is best for the purpose.

Blood Will Tell. In the test cities, the Census Bureau mailed invitations to about 8,000 men; in each city, about 800 replied and attended a selection meeting. Those chosen had to be in apparent good health, with no history of heart-artery disease. They had to be married, and have a stable job and a home with a food freezer. They gave blood samples for cholesterol measurements before they started on their diets, and have given them every two months since.

In each city, the D-H food center delivers its computer-selected lean meats, the meat specialties such as “grillettes,” sausage and chicken a la king, and the defatted milk substitutes, cheeses, spreads, creamless ice cream—and margarine. Volunteers buy many staples, fish, fowl and fruits in the open market. Just how many different diets are being tried in the study is still secret.

The volunteers were asked to eat out only two meals a week, and then to pick and choose carefully from the menu or whatever a hostess serves. Do the boys cheat? Not much, say the know-it-all computers, which not only select menus but tabulate the results of frequent checkups. Bimonthly blood-cholesterol levels would tattle on any secret gorgers. Most of the men have lost weight—five to eight pounds on the average.

Whatever the precise composition of the secret diets, they are based on far more sophisticated nutrition science than simply cutting down on fats and boosting the proportion of polyunsaturates. For one thing, it probably does no good to cut down fats and make up the calorie deficit with carbohydrates: the Rockefeller Institute’s Dr.

Edward H. Ahrens Jr. has shown that one effect of this maneuver is to boost the triglycerides in the blood. And more and more heart researchers are coming to believe that the triglycerides are at least as important as cholesterol, and perhaps a better clue to the risk of a heart attack. Oakland’s Dr. Laurance Kinsell has found that some people have high triglycerides and normal cholesterol, while others have high cholesterol and normal triglycerides.

Microscopic Giants. Dr. Margaret Al-brink, now at West Virginia University, began a triglyceride study in 1955 when she was at Yale. She says it is the triglyceride level, and not the sheer volume of cholesterol, that determines whether the cholesterol will circulate in harmless little molecules or form “giant” (though still microscopic) particles of the kind that clogs up arteries. Adds Dr. Al-brink: “The single most important thing that influences the triglyceride concentration is excessive weight gain after 25. Triglycerides increase with too many calories, while cholesterol increases with too much fat.”

With so much emphasis on what to eat and how much, some authorities despair of getting the public to recognize that heart disease has no single, simple cause. Hereditary susceptibility is a factor, and so is high blood pressure. Says Dr. Paul Dudley White, lean, beanpole dean of cardiologists: “We’re trying to establish the degree of responsibility for a number of different factors. For instance, muscular metabolism, and the effects of vigorous exercise.” Dr. William B. Kannel, assistant director of a ten-year-old study of more than 5,000 men and women in Framingham, Mass., says: “Cigarette smoking triggers a great amount of coronary disease. If we could abolish smoking, we could reduce the deaths from coronary disease in Framingham by 40%. The risk is related to how much you smoke, but not to how long you have smoked. Those who stop smoking have as good a chance of escaping heart disease as nonsmokers.”

Everywhere, eager researchers are trying to pin down the importance of stress and how it affects the heart. The University of Oklahoma’s Dr. Stewart Wolf led a team of cardiologists into the little Pennsylvania town of Roseto, where 95% of the 1,600 inhabitants are descended from a single group of immigrants from Italy. They eat heavily, including plenty of saturated fat, and drink a lot of wine. Nearly all of them are overweight. But to their surprise the doctors found that in seven years no Roseto men under 47 died of heart attacks, and in later life their rate was barely half that in neighboring towns. Perhaps, the investigators say, the explanation is that these people are “gay, boisterous and unpretentious, simple, warm and very hospitable . . . mutually trusting (there is no crime in Roseto) and mutually supporting.” When Rosetans leave home to live in the big cities, their heart-attack death rate goes up to the U.S. norm.

Red Cells Merge. Basic to any understanding of the role of stress, says San Francisco’s Dr. Meyer Friedman, is the individual’s personality. Does he seek out stresses? And does his body react to them in a way that will eventually kill him by clogging his coronary arteries? Dr. Friedman thinks so.

A driving go-getter, he says, cannot clear his bloodstream fast enough of the triglycerides which accumulate after a high-fat meal. Unlike the more placid man, the go-getter uses too much of his body’s heparin to break up the fat. There is not enough heparin (nature’s anticoagulant) left to keep the red blood cells apart: “If, after every meal, a man has too many fat particles going around and red cells sludging and obstructing small blood vessels, the heart may be temporarily so embarrassed that this man will have a heart attack without a clot. This may explain why 30% to 40% of all autopsies after heart attacks reveal no clot.”

In the D-H study, now beginning its second year, some volunteers will be given more freedom to buy their own lean meats. Next summer, the computers will render their verdicts on this and other variables in the volunteers’ diets. Then the PHS will decide whether to launch a ten-year study of 100,000 men to settle, once and for all, the vexed questions of fats and the heart.

*Chemists call a fat saturated if each carbon atom along the molecular chain has hydrogen atoms attached. It is monounsaturated if one carbon atom is free of the hydrogen bonds; it is polyunsaturated if two or more are free. *Amid a plethora of diet books, a new edition of Jolliffe’s Reduce and Stay Reduced on the Prudent Diet (Simon & Schuster; $4.95) is the biggest seller.