Understanding Cholesterol : Healthy Eating for All

by Food and Drug Administration (FDA)

(Page 2 of 2)

Because people with high blood cholesterol have a high rate of heart disease, because a low-fat diet can reduce blood cholesterol levels, and because "the magnitude of the problem posed by elevated blood cholesterol levels is very clear," NCEP on Feb. 27 recommended that all Americans over 2 reduce the saturated fat and cholesterol content of their diets.

FDA, along with a coalition of 38 federal agencies and health organizations, endorsed the recommendation. F. Edward Scarbrough, Ph.D., acting director of FDA's office of nutrition and food sciences, points out that disease may develop from many years of eating a diet high in saturated fat and that dietary habits are established long before an individual is diagnosed with coronary heart disease. "Eating a healthy diet makes good disease prevention sense in general," says Scarbrough.

Good disease prevention, according to the new NCEP recommendations, includes a diet containing:

• less than 10 percent of total calories from saturated fatty acids
• lan average of 30 percent of total calories or less from all fat
• ltotal calories necessary to reach or maintain a desirable body weight
• lless than 300 milligrams of cholesterol per day.

According to the report, the major decrease in total fat should be in calories from saturated fatty acids. Saturated fat raises blood cholesterol more than anything else in the diet, even more than dietary cholesterol. Saturated fats usually are solid at room temperature. They are present in largest amounts in animal products such as butter, cheese and meat. (Whole milk, which has a relatively high saturated fat content — 5.1 grams in 8 ounces — is one exception to this general guideline.)

Survey data from USDA's Human Nutrition Information Service show that saturated fatty acids make up 13.2 percent of total calories in the average American's diet. If the new recommendations are followed, this would mean an average reduction of slightly over 3 percent of saturated fat in the average diet.

Unsaturated fats (polyunsaturated and monounsaturated) are healthy substitutes for saturated fat. Vegetable oils such as safflower, corn, soybean, cottonseed, sesame, and sunflower oils are good sources of polyunsaturated fats. These fats should provide up to, but no more than, 10 percent of total calories, according to the report. Monounsaturated fats — from oils such as olive, peanut and canola — should provide remaining fat. According to the report, Americans should slightly increase their intake of unsaturated fats.

Cholesterol is found only in food from animal sources, such as egg yolks, dairy products, meat, poultry, shellfish, and — in smaller amounts — fish. Also, organ meats — liver, for instance — are particularly rich in cholesterol.

According to USDA survey data, the average daily intake of dietary cholesterol is 304 milligrams for women and 435 milligrams for men. This means most women should slightly reduce their cholesterol intake, while most men should reduce it significantly (by 135 milligrams daily).

Mixed Messages

Cholesterol is now a household word. In their weekly trips down supermarket aisles, grocery store shoppers can't escape messages about low cholesterol. Children come home with warnings about cholesterol from school health classes. Many runners and walkers and just about anyone who regularly lifts weights in a fitness center can recite their blood cholesterol level as automatically as their birth date.

Popularity of the "C" word has accompanied a growing interest in health, along with concern about disease. So, new information about the possible cholesterol-lowering benefits of some foods is an immediate attention-getter. The problem is that, just as understanding of the links between diet, high blood cholesterol, and coronary heart disease has evolved slowly, so has our scientific understanding about the effects of different nutrients on blood cholesterol levels progressed slowly.

Oat bran became an immediate hit in the late 1980s as scientific studies, such as a 1986 project from Northwestern University, seemed to show this soluble fiber could lower blood cholesterol levels. Dietary fiber became an issue, as researchers questioned how oat bran affects blood cholesterol levels. While some scientists believed that it might directly affect blood cholesterol levels, others speculated that the chief effect of oat-bran consumption is simply that people substitute it for high-fat foods.

The stage was set for a research study from Boston's Brigham and Women's Hospital and the Harvard Medical School that found high-fiber (like oat bran) and low-fiber diets had the same cholesterol-lowering effect. Along with the amount of fiber they ate, participants reduced their consumption of foods high in fat and dietary cholesterol. Researchers concluded that oat bran consumption does not directly affect blood cholesterol levels. However, when people eat more oat bran, they often reduce their intake of other foods high in saturated fat — thus producing the cholesterol-lowering effect.

When this study was published in the Jan. 23, 1990, issue of the New England Journal of Medicine, it made front-page news and precipitated stock market speculations about the fall of oat bran, the miracle cure-all.

Olive oil, high in monounsaturated fat, shared the same fate. Results from a study of 4,903 Italian men and women showing that olive oil consumption was associated with lower blood cholesterol levels were published in the Feb. 2 issue of the Journal of the American Medical Association. Other recent research also has suggested that monounsaturated fats may be good for your heart.

The March 1 issue of the New England Journal of Medicine, however, reported findings from a Columbia University study concluding that monounsaturated fats are no more beneficial than poly- unsaturated fats. The newspapers that day carried headlines such as "Olive Oil's Benefits Don't Pan Out."

Similarly confusing messages have resulted from recent research on other products as well. New studies seem to suggest that while caffeine may trigger heart rhythm abnormalities, drinking decaffeinated coffee may raise blood cholesterol levels. And, while egg yolks contain large amounts of dietary cholesterol, recent USDA data, based on new testing methods, show that the cholesterol content of the average large egg is lower than previously thought. According to the latest measurements, a large egg contains 213 milligrams of cholesterol per egg, not the 274 milligrams reported in earlier published data.

What to Do?

These mixed messages nevertheless continue to point to the same healthy advice: Eat a diet low in fats, especially saturated fats. Don't throw away your oat bran, but don't rely on it solely either. Get your nutrients from a variety of foods. You don't have to throw out your eggs either — but eat egg yolks in moderation.

No one food will magically lower your blood cholesterol level. But the low-fat diet recommended by NCEP will hurt no one and was designed to help most Americans.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.