Oct. 22, 2012 -- Adding beans and other legumes to the diet appears to help people with type 2 diabetes improve their blood sugar control and lower their risk of heart disease, according to new research.
Two diets were tested in 121 men and women with type 2 diabetes. Both diets were healthy, but one added legumes, such as chickpeas, lentils, and beans.
"People with diabetes did better in terms of blood sugar control on the bean diet versus a diet without beans, which was otherwise extremely healthy," says researcher David J.A. Jenkins, MD, PhD, DSc, professor of medicine and nutrition at the University of Toronto and St. Michael's Hospital in Toronto.
The bean diet lowered the predicted risk of heart disease more, too, Jenkins says. And it did so in a way that surprised him, he says. "It reduced heart disease risk predominantly because of its effect on blood pressure," he says.
While Jenkins is a backer of the bean diet, a nutrition expert who wrote a commentary published with the study questions if the beans deserve the credit, or the high fiber in the bean-heavy diet.
The study and commentary are published online in the Archives of Internal Medicine.
The study was funded by Canada's federally funded ABIP (Agricultural Bioproducts Innovation Program) through the Saskatchewan Pulse Growers (legumes) and PURENet (Pulse Research Network).
Legumes are known as low glycemic index foods. The index measures the effects of sugar in food on blood sugar. Jenkins says legumes have been shown to improve blood sugar control in people with type 2 diabetes.
Jenkins assigned half the men and women to follow a healthy diet high in wheat fiber. They ate whole grain cereals, low-fat dairy, and fruits and vegetables, he says. The other half was told to eat a healthy diet, including a cup of legumes per day, or about two servings.
Each group got a checklist of recommended foods and quantities to eat every day.
The study lasted three months.
Beans and Blood Sugar: Results
The bean diet improved blood sugar control more, as measured by the HbA1C test.