High-Fiber Cereal Cuts Excess Insulin Production
Issue 217 Item 9

Dietary fiber can help to prevent so-called hyperinsulinemia, therefore helping to ward off full-blown diabetes.

People in danger of developing type 2 diabetes often have high levels of insulin; because they are “insulin resistant,” glucose is not processed properly and the pancreas compensates by producing more insulin. Now, a study in the medical journal Diabetes Care suggests that dietary fiber might prevent so-called hyperinsulinemia — and perhaps help ward off full-blown diabetes.

Dr. Thomas M. S. Wolever, of the University of Toronto, Canada, and colleagues compared the effect of high-fiber cereal versus low-fiber cereal on glucose and insulin in 77 non-diabetic men, of whom 35 had normal fasting insulin levels while 42 had high levels.

Those with hyperinsulinemia were significantly heavier and had large waist circumferences than the normal-insulin group. Hyperinsulinemic men also had lower HDL (“good”) cholesterol and a trend toward higher triglyceride levels.

The participants were studied on two occasions after 10- to 14-hour overnight fasts. The two test cereals contained the same amount of carbohydrate but different amounts of fiber.
In both groups of men, blood glucose levels rose less after they ate the high-fiber cereal than after the low-fiber cereal, Wolever and colleagues report.

Also, in the hyperinsulinemic men, the high-fiber intake reduced the rise in peak insulin compared with that seen after the low fiber meal. In the normal insulin men, the rise in insulin after eating was the same with both types of cereal.

While the results suggest dietary fiber helps control insulin responses, the team concludes that longer studies “are required before conclusions can be drawn as to whether a high-fiber breakfast cereal has any long-term benefits for the management of insulin resistance or obesity.”
Diabetes Care, June 2004