Eating more cereal fibre may help reduce the risk of type-2 diabetes in women, while foods high on the glycemic index may increase the chances of developing the condition, according to two studies.
In the studies, printed in the Archives of Internal Medicine, researchers looked at the effects of the two types of foods on type-2 diabetes in Chinese women and in African-American women.
The results add weight to the benefits of adding fibre to your diet in order to reduce the changes of developing diabetes, and present further opportunities for companies to develop innovative new ways to increase fibre intake.
Classed as an epidemic by the World Health Organisation, at least 171m people worldwide suffer from diabetes, a figure likely to more than double to 366m by 2030. The American Diabetes Association estimates that at least 90 per cent of the 17m Americans diagnosed with diabetes have type-2.
In one study, Supriya Krishnan, of Boston University School of Public Health, and colleagues examined data from 40,078 US 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. The women answered follow-up questions every two years 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 fibre from grains had a reduced risk.
Krishnan's results showed that those women with a body mass index (BMI) of less than 25, who ate about 1.5 grams of fibre 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. This can contribute to problems with the pancreas, which produces insulin, and may eventually lead to diabetes, the researchers said.
Krishnan said: "Our results indicate that women can reduce their risk of diabetes by eating a diet that is high in cereal fibre.
"Incorporating fibre sources into the diet is relatively easy: a simple change from white bread to whole wheat bread or substituting a cup of raisin bran or oatmeal for a cup of corn chex or rice chex will move a person from a low fibre intake category to a moderate intake category, with a corresponding 10 percent reduction in risk."
A second study led by Raquel Villegas of Vanderbilt University Medical Center followed a group of 64,227 Chinese women for an average of five years.
During the study, 1,608 of the women developed diabetes. Women who consumed more carbohydrates overall were more likely to develop diabetes, they found.
The team noted that 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.
Villegas noted that: "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."
NutraIngredients.com had not seen the full results of the study prior to publication.