Very High Fiber Diet Lowers Blood Glucose in Diabetics

A study published in the May 11, 2000 issue of The New England Journal of Medicine reports that diabetic patients who included 50 grams of fiber in their daily diet lowered their glucose levels by 10%. Fifty grams is a lot of fiber: about twice as much as the American Diabetes Association recommends, and nearly 3 times as much fiber as most Americans consume in a day.

The high-fiber diet also decreased insulin levels in the blood and lowered blood lipid concentrations in study patients with type II diabetes, or non-insulin dependent diabetes mellitus, the most prevalent type of diabetes.

The authors, Dr. Abhimanyu Garg and Dr. Manisha Chandalia, say that their results should encourage diabetics to pay more attention to the fiber content of the foods they eat. "Diet is the mainstay of diabetes treatment but is often neglected," Garg said. "The study supports the view that diet can improve glucose and lipid levels and thus reduce the risk of long-term diabetic complications."

The study was conducted at the University of Texas Southwestern Medical Center. Thirteen patients, 12 men and one woman, participated. Each patient ate the high-fiber diet or the moderate-fiber diet recommended by the American Diabetes Association (ADA) for 6 weeks, then switched to the other diet for 6 weeks. Both diets contained the same number and proportion of calories from carbohydrates, fats and proteins. Blood tests were made during the final week of each diet.

The ADA diet had 24 grams of fiber (8 grams of soluble fiber and 16 grams of insoluble fiber), while the high-fiber diet had 50 grams of fiber (25 grams each of soluble and insoluble fiber). Fiber is classified according to water solubility. Most foods, such as fruits, vegetables and grains, contain both types of fiber.

The high fiber diets were specially prepared, and the fiber content of the high-fiber diet was achieved by incorporating foods naturally rich in fiber, particularly soluble fiber. Fiber supplements were not used. Foods provided to the patients included cantaloupe, grapefruit, oranges, papayas, raisins, beans, okra, sweet potatoes, winter and zucchini squash, granola, oat bran and oatmeal.

Three of the patients were treated with diet alone, and the other 10 were treated daily with 2.5 to 20 milligrams of glyburide (a medication used to treat diabetes) in addition to the diets. The glyburide dose remained constant throughout the study.

On the basis of previous studies conducted by Garg, the ADA suggests a diet rich in monounsaturated fats, like those consumed in Mediterranean countries. The current study supports another, less-emphasized aspect of the Mediterranean diet: the fruits, vegetables and grains, which are rich sources of dietary fiber.

http://healthlink.mcw.edu/article/958073584.html
© 2003 Medical College of Wisconsin

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