NEJM Study Shows Fiber's Great Benefits in Type 2 Diabetes

Question Remains: How Can Clinicians Get Patients to Eat More Fiber?

BOSTON — May, 2000 — An article in this week’s New England Journal of Medicine suggests that people with type 2 (adult-onset) diabetes can lower their blood sugars significantly by increasing the amount of fiber in their diet beyond the levels currently recommended by the American Diabetes Association.

While the study sheds important additional data on the importance of fiber in helping keep blood sugars under control, both the study’s authors and Joslin Clinic’s Director of Nutrition Services Karen Chalmers, MS, RD, CDE, note that clinicians haven’t been very successful in getting patients to eat even as much fiber as the ADA currently recommends.

"As pointed out in this most recent study, research findings to date have been inconsistent on the role of fiber in controlling blood sugar in people with type 2 diabetes, leaving health professionals uncertain how much to push patients with type 2 diabetes to eat fiber," Chalmers said.

"This new study reinforces the importance of encouraging patients with type 2 diabetes to eat fiber. However, the amount of fiber used in the study is nearly double the 24 grams recommended by the American Diabetes Association. We can't get people to eat the 24 grams of fiber, so how practical is it to expect them to eat 50 grams?" Chalmers said.

In an editorial accompanying the article, Marc Rendell, MD, of the Creighton Diabetes Center in Omaha, NE, observes that "In part, this failure is due to the lack of a concerted educational campaign like those that led to recognition of the role of unsaturated fats in reducing serum cholesterol concentrations. In addition, there is insufficient awareness on the part of physicians of the benefits of dietary treatment."

Chalmers and Rendell both agree that healthcare professionals seldom have the time in visits with patients in the current healthcare reimbursement climate to invest the time needed to provide patients with regular dietary counseling and follow-up.

Yet the benefits shown in this study of increasing dietary fiber in patients’ diets is similar to that typically obtained by adding another oral anti-diabetic medication to a patient’s treatment plan. Increasing medication is usually needed to keep blood sugars under sufficiently good control to prevent diabetes’ devastating complications, which include kidney disease, stroke, heart attack, eye and nerve damage and other problems.

Type 2 diabetes, which affects an estimated 15 million Americans, occurs when the body is unable to produce adequate amounts of insulin or is unable to use the insulin produced to convert food in the form of glucose into energy. While it is unclear exactly how fiber keeps blood sugars in check, it is believed that part of the benefit lies in the fact that fiber takes longer to digest and slows the release of glucose from food into the blood stream, allowing a type 2 diabetes patient’s own insulin production system to have a better chance of converting the glucose into energy.

Foods containing soluble fiber, such as oat and rice bran, apples, dried peas and beans, barley, seaweed, fruits and vegetables, were shown to be the most effective in lowering blood sugars. Soluble fiber dissolves in water, absorbs water and slows the passage of food. Unlike many previous studies, the fiber in this study was obtained from regular unfortified foods and no fiber supplements were used.

Chalmers notes that if patients decide to add fiber to their diets, it is important that they begin to increase fiber GRADUALLY (by 3-5 grams/day) to prevent bloating. Also, at least 8 cups of decaffeinated beverages need to be consumed each day, as a high fiber diet without enough fluid can lead to constipation.

"What this study shows is that it is important — and obviously beneficial — to encourage patients with diabetes to increase the amount of fiber in their diet," says Chalmers. "And to get the word out over and over again to patients, their physicians and the public about the benefits of fiber to people with type 2 diabetes. Equally important, we need to have insurers recognize the benefits of providing health care professionals with the time — and compensation through insurance reimbursement — to provide patients with regular dietary education and follow-up."