High-fiber bran diets reduce cholesterol levels - oat bran; includes recipes

Better Nutrition (1989-90), March, 1990 by Frank Murray

High-Fiber Bran Diets Reduce Cholesterol Levels

Cutting serum cholesterol isn't all that oat bran can do. Researchers say it can lower insulin requirements for diabetic patients.

The importance of high-fiber diets, especially those containing oat fiber or beans, has been studied extensively since 1976 by James W. Anderson, M.D., Chief of Medical Service, Veterans Administration Medical Center, Lexington, Ky., and his colleagues. Their studies have shown that fiber is useful in treating diabetes, high blood pressure and obesity, and in reducing cholesterol levels.

Dr. Anderson has determined that high-fiber diets lower insulin requirements and improve glycemic control for diabetic patients. Several of his studies have documented that high-fiber diets lowered insulin requirements by 25 to 50 percent for patients with Type I (insulin-dependent) diabetes mellitus, while improving glycemic control. He added that high-fiber diets offer even greater benefits to Type II patients, those who are not insulin dependent.

"With intensive treatment using high-fiber diets, we have discontinued insulin therapy in more than 80 percent of the lean or obese patients we have treated," Dr. Anderson said. "And using high-fiber diets, we have discontinued therapy with sulfonylureas in almost 90 percent of the Type II diabetic patients we have treated. Others have also documented the beneficial effect of high-fiber diets for Type II diabetic patients." (Sulfonylureas are a class of drugs used to stabilize blood sugar levels.).

Dr. Anderson pointed out that water-soluble fibers are gummy and thus useful in lowering blood glucose and cholesterol levels, while water-insoluble fibers act as roughage and stimulate bowel function. He said that oat products and dried beans are excellent sources of water-soluble fiber and are, therefore, beneficial in lowering cholesterol levels.

"In 1977, we began testing the cholesterol-lowering effects of oat bran," Dr. Anderson said. "Oat bran supplements selectively lowered low-density lipoprotein cholesterol concentrations but did not materially affect the protective high-density lipoprotein cholesterol concentrations."

He said that Dr. R.W. Kirby, a colleague, directed a study reported in the American Journal of Clinical Nutrition, in which 100 grams of oat bran were given to eight men with high cholesterol levels. During the 10-day study, the oat bran reduced their cholesterol values by 13 percent. Their usual diet did not restrict protein, carbohydrate, fat or cholesterol.

The researchers subsequently evaluated oat bran (one bowl of cereal and five oat bran muffins) and dried beans (four servings daily of navy or pinto beans) for 21 days in a group of hospitalized men with high cholesterol counts. Both diets lowered serum cholesterol concentrations by 19 percent and they selectively decreased LDL cholesterol values by 24 percent. The HDL values remained relatively unchanged.

"As our research efforts continue to identify ways that oats and oat bran can be included in the modern diet, it becomes more evident that the product has its own nutritional merit as a cereal food," Dr. Anderson said. "Oats provide good quality protein, complex carbohydrates and dietary fiber. They have little fat and no cholesterol or sodium. Considering oats' additional potential medical benefits for individuals with hypercholesterolemia and/or diabetes, and their ability to fit into `healthful' dietary regimens, oats may be the perfect food for today."

A study reported in the June 1986 issue of the Journal of the American Dietetic Association reported that both oat bran and oat-meal reduced cholesterol levels. The study, performed at the Northwestern University Medical School, was headed by Jeremiah Stamler, M.D., Linda V. Van Horn, Ph.D., R.D., and Kiang Liu, Ph.D.

According to Dr. Van Horn, the volunteers who added oat bran to the American Heart Association diet experienced a mean serum cholesterol reduction of 16.7 mg/dl or 8 percent by the end of the 12-week study. Volunteers who added oatmeal to their diet had a total cholesterol reduction of 19.4 mg/dl or a 9 percent decrease. The control group, which was not given oats, had a total reduction of 9.5 mg/dl or a 5 percent decrease in cholesterol levels.

Dr. Van Horn said that the cholesterol reduction among the oatmeal group was apparently because, although oat bran has more water soluble fiber than oatmeal, the oat bran group tended to eat more oat bran muffins than oatmeal. The oat bran muffin recipe also contained bout 50 mg of cholesterol per serving from egg yolk.

The volunteers were given special recipes using oat bran or oatmeal to use at home. In addition, cereal and muffins made with oat bran and oatmeal were served each day in the testing cafeteria.

In another study, reported in the Journal of the American Medical Association in 1988, Bruce P. Kinosian, M.D., and colleagues at the University of Maryland, Baltimore, reported that oat bran is less expensive than drugs in treating patients with high cholesterol levels.