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Volkoren graansoorten kunnen het risico op type 2 diabetes verminderen.*
- Consuming a diet rich in whole grains may help overweight adults to reduce their risk of type 2 diabetes, according to a recent report. The study found that insulin sensitivity improved in a group of overweight and obese adults when they consumed a diet rich in whole-grain foods such as brown rice, oats, corn and barley. Insulin sensitivity is a measure of how efficiently the body responds to insulin, the hormone responsible for depositing glucose (sugar) from the blood following a meal or snack, into cells throughout the body to use as energy. Patients with type 2 diabetes become desensitized to insulin and as a result, their blood glucose can remain elevated. If not controlled through diet or medication, elevated blood sugar eventually raises the risk of heart disease, kidney damage and other problems. "Insulin sensitivity may be an important mechanism whereby whole-grain foods reduce the risk of type 2 diabetes and heart disease," Dr. Mark A. Pereira from Harvard University in Boston, Massachusetts, and colleagues conclude. The findings support the US Department of Agriculture's (USDA) recommendation to consume six to 11 servings of carbohydrates daily, including servings from whole grain sources. In the US, the majority of grains are refined, meaning they have been stripped of their bran and depleted of fiber, minerals and other healthy compounds. But studies have shown that fiber may slow the release of glucose into the blood, and lower concentrations of blood sugar require less insulin to be released into the blood. Over time, lower insulin levels may help the cells to remain sensitive to the hormone whereas excess insulin may desensitize the cells. "People should be encouraged to replace the refined-grain foods in their diet, such as white bread and bagels, refined-grain breakfast cereals, and white rice with whole grain choices," Pereira said. He warned consumers to steer clear of products that do not list "whole grain" as the first ingredient. "Often, breads will mention 'wheat flour' on the label but this does not mean that the product is made with the whole grain, including the bran and germ. Often, wheat flour is refined wheat in the form of the common white flour," Pereira said. In the study, 11 sedentary adults with a body mass index (BMI) of at least 27 consumed a diet in which 55% of total calories came from either whole-grain carbohydrates or processed carbohydrates, for 6 weeks. A BMI--a measure of weight in relation to height--of at least 25 is considered overweight, while 30 and above is considered obese. Following the initial 6-week period study volunteers ate their usual diet for 6 to 9 weeks and then switched to the alternate diet for the following 6 weeks. Insulin levels were 10% lower and blood glucose levels were slightly reduced when study volunteers ate a whole grain-rich diet, regardless of body weight, according to the results in the April issue of the American Journal of Clinical Nutrition. Excess weight is a risk factor for insulin resistance, they note. "Whole-grain foods may have favorable effects on insulin sensitivity," Pereira and colleagues conclude. "These effects may reduce the risk of type 2 diabetes and heart disease." SOURCE: American Journal of Clinical Nutrition 2002;75:848-855.(mei 2002)