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Cutting cholesterol.

Cutting Cholesterol

To many people, the name Jeremiah Stamler is synonymous with preventive cardiology. In the 1950s, he was one of the first researchers bold enough to write about preventing (rather than only treating) heart attacks. Stamler has authored over 700 scientific papers and written or edited 22 books. He and his wife Rose are professors on the faculty of the Department of Community Health and Preventive Medicine at Northwestern University Medical School. Last June, while in Washington, D.C. to serve as President of the Second International Conference on Preventive Cardiology, he spoke with NAH's Bonnie Liebman. Q: Is the cholesterol in foods less important than the saturated fat? A: No. There is now ample evidence, since 1981, that dietary cholesterol has an independent effect on the risk of dying of coronary heart disease and all cardiovascular diseases, over and above its effect on blood cholesterol.

Our study of Western Electric employees was the first to show this. We were relatively quiet about it, because you've got to be careful not to draw conclusions from one study. But since then, at least three other studies have shown the same thing. Q: What about animal studies? A: In addition to the human data, there are several sets of animal experimental data. The best experiment was done by Mark Armstrong at the University of Iowa. It's best because it's in monkeys, which are closer to man than rabbits or chickens are.

Armstrong very carefully used a level of dietary cholesterol less than we usually eat. Total blood cholesterol didn't rise at all. But LDL--so-called "bad"--cholesterol went up and HDL --so-called "good"--cholesterol went down. And the monkeys got atherosclerosis, even with no increase in total blood cholesterol. Q: Are you saying that cholesterol-rich foods promote heart disease even in people with low blood cholesterol? A: Yes. And that's why eating less cholesterol must be of concern to all people, irrespective of their blood cholesterol level. Q: By how much does eating less cholesterol reduce risk? A: In the last couple of years, Richard Shekelle of the University of Texas in Houston and I have tried to answer that question. We asked: What is it worth if you're habitually getting 100 mg instead of 300 mg of cholesterol for every 1,000 calories you eat? Based on our Western Electric Study data, it means a 47 percent lower risk of fatal heart attack over the next 20 years for a middle-aged man. That means about 4 years of increased life expectancy. Q: Does that apply to everyone? A: That's for an average middle-aged man. Now consider a middle-aged man who is high risk in everything--who has elevated blood pressure, smokes a pack of cigarettes a day, has high blood cholesterol and high cholesterol intake. If that man eliminates each of these risk factors, he potentially could reduce his risk of fatal heart attack by more than 90 percent. That would mean an increase in life expectancy of more than 20 years. There is no reason to doubt the potential benefits for women as well. Q: How does a drop from 300 mg to 100 mg of cholesterol per 1,000 calories translate into what we actually eat? A: If a woman eats 2,000 calories a day, it means 200 mg instead of 600 mg of cholesterol per day. For a man eating 2,500 calories a day, it's 250 mg instead of 750 mg. And that means, among other things, getting rid of egg yolks. It also means moderate--not huge--portions of lean meat, poultry, or fish, and avoiding fatty dairy and bakery products.

And remember, it's not just the fat you see in the animal products, because every living animal cell--including lean muscle--has cholesterol in its membrane. So even when we eat moderate servings of lean meat, lean chicken, or lean fish, we're getting some cholesterol--about 70 milligrams per 4 ounces--though we may be getting very little saturated fat and total fat. Q: How might cholesterol-rich foods clog arteries other than by raising blood cholesterol? A: We are not sure. We know that dietary cholesterol raises LDL ["bad"] cholesterol even when there's little or no net rise in total blood cholesterol. That's one possible mechanism. There is also evidence that dietary cholesterol increases the tendency of blood to clot. [In the United States, many heart attacks ` occur when a blood clot gets stuck in an already-narrowed artery.] Q: Aren't people with high blood cholesterol at higher risk? A: Absolutely. The relationship of blood cholesterol to risk is massively documented. It applies to healthy people, to those who've had a coronary, to diabetics and non-diabetics, to blacks and whites, to young and old, to women and men.

Even people with cholesterol levels as low as 190 are at increased risk. This is important because it means that 80 percent of Americans have blood cholesterol above the optimal level by the time they reach age 35, 40, or 50. That's why the population as a whole, not just people at higher risk, can benefit from improved eating habits. Q: Doesn't the cholesterol in foods raise blood cholesterol less than the saturated fat? A: You will see repeated claims, both by some scientists who should know the research and by people representing special interests, that dietary cholesterol's effect on blood cholesterol is very weak and inconsequential. Not true.

If a person with an average intake of saturated fat and dietary cholesterol reduces both by the same percentage, the blood cholesterol lowering from the reduction in dietary cholesterol will be about two-thirds as much as from the reduction in saturated fat. So the effect of dietary cholesterol on blood cholesterol is clearly important. Q: What about studies showing that not everyone is sensitive to dietary cholesterol? A: Overwhelmingly, people are sensitive. Those whose total blood cholesterol does not respond to dietary cholesterol are the exception. Those whose LDL ["bad"] cholesterol does not respond to dietary cholesterol are even more rare.

There are undoubtedly differences in responsiveness, but part of the so-called insensitivity is spurious--just chance variation. In other words, when one repeats the study with the same persons, many previous "non-responders" turn out to be responders. Q: Do you advise people to stop eating eggs? A: My wife [researcher Rose Stamler] and I probably eat more eggs than the average family, but we eat only the whites, not the yolks. We throw the yolks in the garbage can.

Rose makes "angeled eggs" instead of deviled eggs. She fills hard-boiled egg whites with tuna--and adds a little mayonnaise and onion. We also make pancakes and waffles with egg whites and a little corn oil. Q: Other than saturated fats and dietary cholesterol, what else influences blood cholesterol? A: Polyunsaturated fats tend to lower cholesterol. Furthermore, the polyunsaturates found in both fish and vegetable oils may lower the risk of heart disease independent of their effect on blood cholesterol. That's still an unanswered question. Q: What do you think of animal studies that indicate an increase in cancerous tumors in animals fed high-poly diets? A: I think that is still an open question. But that possibility is one of the several reasons I agree completely with the recommendation that dietary polyunsaturated fats should be increased moderately, up to--but no more than--ten percent of calories. No population in the world has ever eaten a high-poly diet. The populations with low coronary death rates and better longevity than ours do not ingest a high-poly diet, but rather a diet low in cholesterol and saturates. Q: Do monounsaturated fats lower cholesterol? A: This is something people are very confused about. Replacing saturated fats with either complex carbohydrates or monounsaturated fats lowers cholesterol, because in both cases one gets rid of the saturates.

But is there a further reduction over and above the simple replacement of saturates? In my judgment, the overwhelming evidence says "no." The recent claims to the contrary are based on experiments that show no apparent difference in amount of blood cholesterol fall when either polys or monos replace saturates in the diet. But in my judgment that's only because the studies were too small to detect a difference.

But let me emphasize the importance of eating substantially less saturated fat and cholesterol. If one gets the saturates and cholesterol down low enough with a diet moderate in total fat, it doesn't matter what oil you use for salad dressings--for example, olive oil, which is high in monos, or corn oil, with lots of polys. Q: What do you think of a diet that's low in saturates and cholesterol, but high in monounsaturates? Is it as good as a diet low in all fats? A: In my judgment, no. Fats generally tend to promote blood clots. And fatty diets make it harder to control calories and still get an optimal intake of essential nutrients, including vitamins and minerals. I'm a 20-percent-of-calories-from-fat man. We've been eating wonderfully that way for years. One can readily enjoy the pleasure of eating, it's easier to control your weight, and it's easier to get up from the table satisfied, but not overloaded.

That's not a low-fat diet, by the way. A low-fat diet is less than ten percent of calories from fat. To me, 20 percent is a moderate-fat diet; 35 to 40 percent is high. Look at our cooperative studies of populations in China. The Chinese diet is 20 to 25 percent of calories from fat, is low in saturates and cholesterol, and is high in fiber. The population's blood total, LDL, and HDL cholesterol are optimal, and coronary heart disease remains rare. Q: How about fiber? A: Eaten in reasonable amounts, water-soluble fiber from fruits, beans, and oat products has a modest cholesterol-lowering effect. From the two experiments we've completed, adding about one cup of cooked oatmeal or oat bran per day to the lower-fat diet recommended by the American Heart Association results in a two to three percent drop in blood cholesterol. And if a one percent drop in cholesterol is equal to a two percent decline in coronary risk, every one percent counts. Q: Do you think people should take psyllium, the soluble fiber in laxatives like Metamucil, to lower cholesterol? A: That depends. Let's say a person who has a very high cholesterol--about 290--cuts back on fats, loses weight, and eats foods high in water-soluble fiber. That might bring his cholesterol down to about 250, almost a 15 percent drop. But it's still pretty high.

What to do next? Nothing? Take a medicine like cholestyramine, nicotinic acid, or lovastatin? I'd consider psyllium first. It's a plant product that's been around a long time, and it seems to be safe. Research about psyllium is in progress, and soon we should have much more data on it as a cholesterol-lowering agent. Q: How much does weight loss lower cholesterol? A: For an obese person eating a diet reduced in saturated fat and cholesterol, even 10 pounds of weight loss enhances blood cholesterol reduction by about 30 to 40 percent. So if eating fewer cholesterol-raising fats produces a 10 percent drop, losing weight will lower your blood cholesterol by another 3 to 4 percent. That's obviously important. And, weight loss lowers LDL ["bad"] cholesterol at the same time it raises HDL ["good"] cholesterol. Q: Do you think that cutting back on total fat is the key to weight loss? A: It helps. One other thing, in my experience, is that it's very difficult to make sustained progress in losing and keeping weight off without exercise. One reason I exercise as much as I do is that I have a very good appetite.

I have a few simple formulae for controlling my weight. First, exercise. I do calisthenics every morning, and I swim 50 lengths--2,500 feet--right after work in the pool. It takes 35 minutes.

Second, I eat foods that have few calories but lots of nutrients. Think about a bowl of strawberries versus a bowl of strawberry shortcake. The same number of forkfuls, but the shortcake has six times as many calories from the fats--shortening, whipped cream--and refined sugar.

Third, I eat three meals a day, period. I used to snack between meals. I used to eat supper American-style at six o'clock. After that I'd work, and by 11 o'clock I'd be ravenous. With a can or two of beer, a good sandwich, and fruit, I could consume 1,000 calories without thinking about it. Better to eat supper at eight or nine o'clock. That way we eat only one evening meal. I learned that in Europe. Q: How is your cholesterol? A: I tend to run a high blood cholesterol. I have to be particularly careful. If I eat an old-style American diet, my cholesterol is well above 250. For years, I've kept it between 210 and 230. Also, my blood pressure is optimal and I haven't smoked a cigarette since medical school. I also have high HDL cholesterol, probably from all the exercise, from not smoking, and from not being grossly obese--just a little bit so. So my overall risk is low.
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Title Annotation:interview with Dr. Jeremiah Stamler
Author:Liebman, Bonnie
Publication:Nutrition Action Healthletter
Article Type:interview
Date:Sep 1, 1989
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