Blood Sugar Bows to New Bread

An experimental bread made of ultra-fine-ground whole wheat flour could help Americans up their fiber intake--now considerably below the recommended 25 grams daily--and reduce risk of diabetes in the process. The flour, developed by ConAgra, gives the bread a taste and texture very similar to white bread. But it has six times more fiber.

Nutrition researchers Kay Behall and Judith Hallfrisch at the Beltsville, Md., Human Nutrition Research Center of the USDA's Agricultural Research Service evaluated the bread to see if the particle size would result in a slower increase in blood sugar compared to the sugar syrup given in a glucose tolerance test. A glucose tolerance test indicates a person's potential for diabetes.

The experimental bread improved blood glucose and insulin levels in the 26 volunteers about the same as regular whole wheat bread. Levels stayed lower than when the volunteers ate white bread or consumed a glucose drink. Particle size of the whole-grain flours apparently doesn't make a difference for glucose tolerance, the researchers concluded.

That’s good news because nearly 16 million Americans have diabetes--mostly type 2 diabetes, the kind that usually begins in midlife. Another 13.4 million have elevated fasting blood glucose, putting them at risk for developing diabetes.

Behall and Hallfrisch also compared how much carbohydrate was fermented in the colon instead of being digested in the small intestine. Fermented carbohydrates may reduce risk of colon cancer, some research suggests, but they can also produce gas. Neither particle size nor fiber content affected the amount of fermented carbohydrate. And there was no difference in gastrointestinal distress among the three breads.

According to Conagra’s Glen Weaver in Omaha, Neb., the ultra-fine-ground whole wheat flour has been used in some commercial breads, waffles and other products for about 4 years. But the market is limited because the flour is made from white wheat, rather than the more plentiful red wheat. Weaver is working to gear up U.S. production of white wheat so ConAgra can market the flour more broadly.

Scientific contacts: Kay M. Behall or Judith G. Hallfrisch, Diet and Human Performance Laboratory, ARS Beltsville Human Nutrition Research Center, Beltsville, Md., phone (301) 504-9014, fax (301) 504-9098, [email protected], [email protected].