http://www.sciencedaily.com/releases/2007/11/071126162554.htm

High-glycemic Index Carbohydrates Associated With Risk For Developing Type 2
Diabetes In Women

ScienceDaily (Nov. 27, 2007) - Eating foods high on the glycemic index,
which measures the effect of carbohydrates on blood glucose levels, may be
associated with the risk for developing type 2 diabetes in Chinese women and
in African-American women, according to two new studies. However, eating
more cereal fiber may be associated with a reduced risk for type 2 diabetes
in African-American women.

Researchers remain uncertain regarding exactly how diet, including
carbohydrate intake, affects the development of type 2 diabetes, according
to background information in the articles. Studies have revealed that the
body absorbs carbohydrates from different foods at different rates. This
leads to varying effects on levels of blood glucose and the hormone insulin,
which converts glucose into energy.

Foods high on the glycemic index, such as rice and other simple
carbohydrates, cause a rapid spike and then a drop in blood glucose, whereas
high-fiber foods tend to be lower on the glycemic index and have a more
gradual effect. Some evidence has linked high--glycemic index foods with the
risk of developing type 2 diabetes.

In one study, Supriya Krishnan, D.Sc., of Boston University School of Public
Health, and colleagues examined data from 40,078 U.S. black women who filled
out a food questionnaire in 1995. The glycemic index and glycemic load--a
measure of the amount of carbohydrates from glucose--were calculated. Every
two years through 2003, the women answered follow-up questionnaires about
their weight, health and other factors.

During eight years of follow-up, 1,938 participants developed type 2
diabetes. Women who ate high--glycemic index foods or a diet with a high
glycemic load had a higher risk for diabetes. However, women who ate more
fiber from grains (cereal fiber) had a reduced risk; for women with a body
mass index (BMI) of less than 25, women who ate about 1.5 grams of fiber per
day were 59 percent less likely to develop diabetes than women who ate about
8.3 grams per day.

Because high--glycemic index foods increase blood glucose levels
significantly, they increase the body's demand for insulin, the authors
note. This can contribute to problems with the pancreas (which produces
insulin) that may eventually lead to diabetes. In addition, high--glycemic
index foods can directly decrease the body's response to insulin by
increasing the production of fatty acids after meals.

"Our results indicate that black women can reduce their risk of diabetes by
eating a diet that is high in cereal fiber," the authors write.
"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) or substituting a cup
of raisin bran (5 to 8 grams of fiber) or oatmeal (4 grams of fiber) for a
cup of corn chex (0.5 grams of fiber) or rice chex (0.3 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 another study, Raquel Villegas, Ph.D., of Vanderbilt University Medical
Center, Nashville, Tenn., and colleagues followed a group of 64,227 Chinese
women for an average of five years. During in-person interviews conducted
every two years between 2000 and 2004, the researchers collected data on
dietary habits, physical activity and other health-related information.

During the study, 1,608 of the women developed diabetes. Women who consumed
more carbohydrates overall were more likely to develop diabetes--when they
were split into five groups based on carbohydrate intake, those in the group
consuming the most (about 337.6 grams per day) had a 28 percent higher risk
than those in the group consuming the least (about 263.5 grams per day).
Women who ate diets with a higher glycemic index and who ate more staples
such as bread, noodles and rice specifically also had an increased risk.
Women who ate 300 grams or more of rice per day were 78 percent more likely
to develop diabetes than those who ate less than 200 grams 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 authors
conclude.

Journal reference: Arch Intern Med. 2007;167(21):2304-2309, 2310-2316.

Adapted from materials provided by JAMA and Archives Journals.