TUESDAY, Nov. 27 (HealthDay News) -- Black American women and Chinese women who ate foods high on the glycemic index -- which measures the effect of carbohydrates on blood glucose levels -- were at increased risk for developing type 2 diabetes, two new studies found.

One of the studies also found that eating more cereal fiber may be associated with a reduced risk of type 2 diabetes in black American women.

In one study, Boston University School of Public Health researchers examined data on more than 40,000 black American women who filled out a food questionnaire in 1995. Every two years through 2003, the women provided updates about their weight, health and other information.

During those eight years of follow-up, 1,938 of the women developed type 2 diabetes.

Women who ate high-glycemic index foods or ate a diet with a high glycemic load were more likely to develop diabetes. Women who ate more cereal fiber were less likely to develop diabetes.

"Our results indicate that black women can reduce their risk of diabetes by eating a diet that is relatively high in cereal fiber," the study authors wrote. "Incorporating fiber sources into the diet is relatively easy: A simple change from white bread (two slices provides 1.2 grams of fiber) to whole wheat bread (two slices provides 3.8 grams of fiber) ... will move a person from a low fiber intake category to a moderate intake category, with a corresponding 10 percent reduction in risk."

In the second study, researchers from Vanderbilt University Medical Center in Nashville, Tenn., followed more than 64,000 Chinese women for an average of five years. During the study, 1,608 of the women developed diabetes.

High consumption of carbohydrates increased the risk of diabetes. Women who consumed the most carbohydrates (about 337.6 grams per day) had a 28 percent greater risk of developing diabetes than those who consumed the least (about 263.5 grams per day).

Women who had high glycemic index diets and who ate more food staples such as bread, noodles and rice also had an increased risk. For example, those who ate more than 300 grams of rice per day were 78 percent more likely to develop diabetes than those who ate less than 200 grams of rice per day.

"Given that a large part of the world's population consumes rice and carbohydrates as the mainstay of their diets, these prospective data linking intake of refined carbohydrates to increased risk of type 2 diabetes mellitus may have substantial implications for public health," the researchers concluded.

More information

The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about type 2 diabetes.

-- Robert Preidt

SOURCE: JAMA/Archives journals, news release, Nov. 26, 2007

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