The Cholesterol Question : Contradictory interpretations of clinical trials and population studies have done little to clarify the role that dietary cholesterol plays on the risk for heart disease.

Recent scientific research says that oat bran probably isn’t the cornerstone of lowering cholesterol in the bloodstream. And in what appears to be another reversal of science, some experts now explain that lowering dietary cholesterol may not be at the heart of preventing cardiovascular disease in Americans.

Although most data does appear to support a strong link between blood cholesterol and risk in the heart-disease mosaic, there’s still plenty of disagreement on whether or not dietary cholesterol is a factor.

Researchers, eager to provide insight into this country’s disproportionate rate of coronary heart disease (CHD) and its complications, have conducted study after study of the effect of high cholesterol intake on heart health in both humans and animal subjects, but thus far the data merely suggests a connection.

Depending on the way their results are interpreted, clinical trials and population studies can either validate or invalidate the need to restrict cholesterol consumption in an effort to reduce risk for coronary heart disease.

At least half of the researchers and health experts in the field believe the research supports the idea that a prudent diet--one that limits intake of dietary cholesterol--can be of benefit. The opposing view is that these researchers have led consumers on an unnecessary cholesterol witch hunt that has contributed to the confusion about nutrition felt by many Americans.

But Americans, caught in the middle of the battle, have sought their own solutions to the problem. In this country, people have systematically eliminated entire food categories such as eggs, meat and dairy products from their diets and replaced them with foods with a perceived health benefit, an option that frequently has its own ill effects.

The relationship between heart disease and cholesterol “is more serious than that,” said Dr. Peter O. Kwiterovich, director of the Lipid Research Clinic, Johns Hopkins School of Medicine, and author of the book, “Beyond Cholesterol: The Johns Hopkins Complete Guide for Avoiding Heart Disease (Johns Hopkins Press: 1989).

“There are no quick fixes,” he explained, “(preventing heart disease) requires a life-style change.”

Kwiterovich is among the many members of the scientific community who continue to hammer out the intricacies of cholesterol metabolism by the body and who also share a general belief that dietary cholesterol has a role in risk for CHD.

While experts disagree on whether or not there is a direct correlation between increased dietary cholesterol and cardiovascular disease, most concur that scientific data suggests an indirect connection.

It is known that high blood cholesterol is a risk factor for CHD and dietary cholesterol raises blood cholesterol. But since age, heredity, obesity, exercise and gender also influence blood cholesterol levels, the debate centers on just how important dietary cholesterol is, with some saying it isn’t--at all.

The human body has a sophisticated system of checks and balances that seeks to maintain a desirable level of cholesterol in the bloodstream--an amount determined by heredity. This much is known.

On one side of the issue, experts say this delicate balance can be disrupted with prolonged, high-cholesterol intake. They even report that those people who maintain a consistently low-fat, low-cholesterol diet have an exceptionally good response to periodic fluctuations in dietary cholesterol intake.

The opponents, however, claim that a prudent diet has little or no effect on this system. In their assessment of the science, there is only a small percentage of the population that can benefit from restrictive diets because the body will maintain this balance--even during periods of excess. Or, after a time of marked elevation, it will eventually return to its genetically determined level.

Cholesterol is a wax-like compound found only in animals and serves a variety of functions in the body. It is a component of bile, an element necessary for digestion. And it is the starting material from which hormones are made. It is part of every cell, and the body is capable of making all the cholesterol it needs for proper functioning. This could be considered an individual’s base-line cholesterol level--the amount circulating in the blood before any cholesterol-containing food is eaten.

Cholesterol, like other members of the lipid family, is carried throughout the body by lipoproteins (protein-like particles), of which there are three distinct types. Low-density lipoproteins (LDL), high-density lipoproteins (HDL) and very-low lipoproteins (VLDL).

LDL is made by the intestine and liver for transport of fats around the body. Its concentration in the blood may be increased by consuming diets rich in saturated fatty acids or substantial amounts of cholesterol. Because it tends to rest in blood vessel linings, it is associated with a high heart attack risk and has been dubbed the “bad” cholesterol.

HDL also is responsible for carrying cholesterol around the body, but it serves to remove cholesterol from its storage sites to the liver for dismantling and disposal from the body. That’s why it is given the distinction of the “good” cholesterol.

VLDL primarily carries triglycerides and is not typically related to heart disease.

In healthy people, Kwiterovich explained, cells contain LDL receptors that allow them to synthesize cholesterol when blood supplies are low. They can use the extra cholesterol in the blood rather than making more cholesterol of their own during periods of dietary increase of the substance and compensate by making more when blood cholesterol levels are low.

This balance can, however, be disrupted when a diet contains large quantities of saturated fat or cholesterol-rich foods over a consistent period of time, Kwiterovich said. When this occurs, the body learns to adapt to prolonged, excessive cholesterol intakes (usually above 500 milligrams per day), and it eventually develops a reduced capability to adjust to dietary cholesterol fluctuations.

(There also is a small minority of people who suffer an inherited tendency called insensitive feedback mechanism. In this scenario, the cells are inherently insensitive to their surrounding climate and have difficulty adjusting to changes in dietary intake. With malfunctioning LDL receptors, the cells make the same amount of cholesterol whether the diet is high or low in cholesterol. Then, if dietary cholesterol intake increases, the cells continue their own synthesis of the substance, plus, they absorb the extra cholesterol from the diet.)

Kwiterovich explained that in both normal individuals and those with insensitive feedback mechanism, saturated fat and dietary cholesterol cause a decrease in the number of LDL receptors existing in the liver cells, which means less of the cholesterol in the blood can be disposed of.

But, he contends, if the saturated fat and cholesterol content of the diet is cut back, the number of LDL receptors in the liver will rise. Thus, the blood LDL cholesterol level will fall. Furthermore, he said, people who are already on low-fat, low-cholesterol diets may be much less affected by additional changes to their diets because their LDL receptors are already performing at the maximum rate.

That is why diet is important to everyone, he said, and he used the now famous Harvard oat bran study, to explain.

The participants in this trial were already following a diet very low in cholesterol and saturated fat and they had a generally low blood cholesterol level--186 milligrams per deciliter (200 is considered a moderate range). They were given a source of soluble fiber (oat bran) but a very small reduction was demonstrated. That’s because, said Kwiterovich, they were “at a point where the LDL receptors can’t be effected anymore. . . . They were already breaking down cholesterol at the maximum rate.

“There is evidence now that high saturated fat diets suppress LDL receptors; therefore, there are not as many available to remove LDL cholesterol from the body as efficiently,” he said.

But opponents of this view--including Thomas J. Moore, whose recent book, “Heart Failure” (Random House: 1989), was spotlighted in September’s Atlantic magazine--use the same data to contradict the need for a diet of moderation.

He claims that there are some people for whom restriction of dietary cholesterol will be ineffective against increasing blood cholesterol levels, so diet isn’t that significant. He said that the dangers of high blood cholesterol levels have “frequently been exaggerated.”

Moore and other authors, including Fredrick J. Stare, Robert E. Olson and Elizabeth M. Whelan in their book “Balanced Nutrition: Beyond the Cholesterol Scare” (Bob Adams Publishers: 1989), report that although dietary cholesterol does “exert a minor upward effect” on blood cholesterol levels, it does so only in some people. They say blood cholesterol is simply a risk factor, not a sign of the disease.

The authors write: “If you’re are a physiologically normal individual, your body constantly monitors what comes in and alters its own production of cholesterol in order to keep body stores constant and guarantee essential functions. And even in those people who exhibit modest short-term serum (blood) cholesterol increases or decreases due to diet, there is a general tendency in most for the serum cholesterol--over a period of years--to return to genetically determined levels.”

But this hypothesis begs the question: “How long should an individual wait?”

What appears to be more of an issue--and it is a point upon which both sides concur--is that there is a flaw in most of the studies that are at the center of the dispute. And this point is probably more important to consumers than whether or not there’s a direct correlation between dietary cholesterol and heart disease.

Because of inherited differences among people, it is important to identify a person’s threshold--the beginning point at which dietary cholesterol can cause a measurable increase in blood cholesterol--and one’s ceiling, the point at which you can add more and more cholesterol to the diet and not effect the content of the blood. This way it is possible to eliminate the broad brush-stroke approach to general population health and tailor prevention and treatment to the needs of the individual.

It has been pointed out that there are some species of animals that have a very high threshold. Carnivorous birds, rats and gophers, for example, survive on a diet of raw flesh, so they are genetically adapted to a meat diet. Although they eat a high cholesterol, high saturated fat diet, they have an inherited high HDL cholesterol level--the type that carries excesses out of the body and has been named the “good” cholesterol.

On the other hand, there are animals such as rabbits and chickens that are genetically adapted to a vegetarian diet and a high cholesterol/high saturated fat diet is unhealthy for them.

One researcher has suggested that humans fall somewhere between these extremes--each person with an inherited barometer for safety, but without this knowledge of heredity it is difficult to prescribe recommendations.

Until this very visible disagreement over the body’s ability to adjust to long-term high intake of dietary cholesterol and whether there is actually a point-of-no-return above which intake is of little consequence is settled, it’s probably a good idea to watch fat and cholesterol intake, Kwiterovich said.

Conclusive evidence may not be available for some years to come, and since researchers do appear to agree that dietary cholesterol has somewhat of a role in CHD (even if the means by which this information is derived is at times contradictory), it appears that a prudent diet is still recommended for the general population.

It is important to note that this is the same diet advised for overall health. It can help reduce obesity. A prudent diet also regulates blood sugar and is thus recommended for diabetics. And the National Cancer Institute acknowledges that a diet of moderation can reduce risk for developing some forms of cancer.

“We all wear seat belts,” said Kwiterovich, “even though everyone won’t be involved in a fatal accident. So we recommend a healthy diet for all healthy Americans above two years of age--although everyone may not need it.”

THAI CHICKEN SALAD

1 head butter lettuce

3 small chicken breast halves, cooked and julienned

8 large cooked shrimp

1 small cucumber, and shredded

1 red onion, thinly sliced

2 carrots, shredded

2 small tomatoes, cut into wedges

1 tablespoon canola oil

1/4 to 1/2 teaspoon crushed dried red pepper flakes

1/4 cup lemon juice

2 tablespoons rice vinegar

1 tablespoon sugar

Salt

1/2 teaspoon garlic pepper

1 teaspoon grated lemon zest

2 teaspoons fish sauce

Won Ton Spirals

Arrange lettuce leaves on serving platter. Top with chicken, shrimp, cucumber, onion, carrots and tomatoes.

Heat oil in saucepan or wok. Add red pepper and saute 1 minute. Stir in lemon juice, vinegar, sugar, salt to taste, garlic pepper, lemon zest and fish sauce. Stir to heat through.

Pour hot dressing over salad, just before serving. Garnish with Won Ton Spirals. Makes 4 servings.

Note: Fish sauce is available in Thai or Oriental markets.

Won Ton Spirals

2 won ton wrappers

Canola oil

Cut wrappers into 6 strips. Twist to form spirals. Deep fry in hot oil until lightly browned. Allow 2 strips per serving.

DEEP DISH BROWNIE (Beyond Cholesterol)

3/4 cup melted margarine

1 1 /2 cups sugar

1 1/2 teaspoons vanilla

3/4 cup unsifted flour

1/2 cup unsweetened cocoa powder

1/2 teaspoon baking powder

1/2 teaspoon salt

6 egg whites

Combine margarine, sugar and vanilla in bowl.

In separate bowl, combine flour, cocoa, baking powder and salt. Add to margarine mixture and mix well. Beat egg whites until stiff. Fold into mixture until well blended.

Spread batter into 8-inch baking pan sprayed with nonstick vegetable spray. Bake at 350 degrees 40 to 45 minutes for cake-like brownies, 30 minutes for chewy brownies. Cool and cut into squares. Makes 16 servings.

CRISPY POTATO SKINS WITH PAPAYA-BASIL SALSA

1 cup minced tomato

1 cup minced papaya

1 long green chile, roasted, peeled and chopped

1 tablespoon lime juice

1/2 cup chopped red onion

1 clove garlic, minced

Salt

1/2 cup shredded daikon radish

2 tablespoons minced fresh basil leaves

4 baking potatoes

Olive oil

Garlic pepper

Reduced calorie sour cream

Combine tomato, papaya, chile, lime juice, onion, garlic, salt to taste, daikon and basil. Set aside.

Meanwhile, bake potatoes until skins are crisp at 450 degrees 1 1/2 to 2 hours.

Cut into wedges, brush lightly with olive oil and sprinkle garlic pepper. Bake xx minutes longer. Serve with salsa and reduced calorie sour cream. Makes 4 to 6 servings.

ANGEL OMELET WITH VEGETABLE SAUTE

1/4 pound mushrooms, sliced

2 tablespoons canola oil

1 clove garlic

1 cup broccoli florets

1 tablespoon sliced green onions

2 tablespoons diced sweet red pepper

2 serving packets low sodium instant flavor chicken broth

White pepper

1 cup thinly sliced jicama

1/2 cup water

Angel Omelet

Stem mushrooms and chop stems. Slice caps. Saute mushrooms in hot oil in skillet or small wok until tender. Add garlic and saute. Stir in broccoli, red pepper and chicken broth granules. Stir-fry 5 minutes, then add water and jicama and simmer 5 minutes. Season with pepper. Stir in green onion. Serve over Angel Omelet. Makes 4 to 6 servings.

Angel Omelet

1 tablespoon margarine

1/2 cup minced onion

1 clove garlic, minced

8 egg whites

1/2 teaspoon cream of tartar

1/4 teaspoon salt

1/2 teaspoon turmeric

1 tablespoon chopped oregano

1/2 cup shredded low-fat Cheddar cheese

White pepper

Melt margarine in 10-inch nonstick skillet with heat-proof handle. Saute onion and garlic until tender. Remove from pan and set aside to cool.

Beat eggs whites with cream of tartar and salt to stiff peaks. Beat in turmeric, oregano and pepper to taste. Pour into same skillet. Bake at 400 degrees 15 minutes. Do not remove from oven. Sprinkle with cheese and heat until cheese is melted. Makes 4 to 6 servings.

Note: Omelet is more like souffle, so serve immediately. It will fall upon standing.

MERINGUE SHELL WITH FRUIT AND CUSTARD

1/4? cup sugar

1/4 cup flour

Dash salt

1 1/2 cups low-fat milk

1/2 cup egg substitute, thawed

1 teaspoon vanilla

Meringue Shell

Mixed berries or other desired fruit

Strawberry Sauce

Combine sugar, flour and salt in medium saucepan. Gradually stir in milk. Cook and stir over medium heat until thickened and bubbly. Reduce heat and cook and stir 2 minutes longer. Remove from heat.

Beat egg substitute slightly, then gradually stir small amount hot mixture into egg substitute. Return egg substitute mixture to saucepan and cook, stirring, 2 minutes. Remove from heat and stir in vanilla. Cool filling slightly, then pour into Meringue Shell. Top with berries. Serve with Strawberry Sauce, if desired. Serve immediately. Makes 8 to 10 servings.

Meringue Shell

Margarine

4 egg whites

1/2 teaspoon cream of tartar

1 cup sugar

Generously grease 9-inch pie plate with margarine.

Beat egg whites and cream of tartar in small bowl of electric mixer until foamy. Beat in sugar, 1 tablespoon at time, until stiff and glossy. Do no underbeat. Spoon into pie plate, pressing meringue against bottom and side.

Bake at 275 degrees 45 minutes. Turn oven off and let meringue stand in oven with door closed 45 minutes. Remove from oven and complete cooling away from draft.

Strawberry Sauce

1 1/4 cups strawberries

1 tablespoon orange-flavored liqueur

Combine strawberries and liqueur in blender container. Blend to puree.

CINNAMON-LACED PANCAKES

1 1/2 cups buttermilk baking mix

1/2 cup oat bran

1 cup nonfat milk

2 egg whites

1/2 teaspoon ground cinnamon

1 tablespoon sugar

Combine baking mix, oat bran, milk, egg whites, cinnamon and sugar. Beat with wire whisk or hand mixer until well blended. Pour scant 1/4 cup onto hot griddle, sprayed with nonstick vegetable spray. Cook until edges are dry. Turn and cook other side until golden. Makes about 17 pancakes.

Food Styling by Minnie Bernardino and Donna Deane. Dinnerware from Arni’s, the Dish Factory