A small study published in the April 2008 issue of Diabetes Care has shown that a diet low on the glycemic index may lead to better blood glucose control in children and adolescents with Type 1 diabetes.
The glycemic index (or GI) is a ranking of carbohydrate-containing foods based on how quickly they raise blood glucose levels. GI values, which range from 0 to 100, depend largely on how quickly a food breaks down in the digestive system. Foods with a higher GI value cause faster rises in blood glucose level after they are eaten. You can read more about the GI in the blog entries “Glycemic Index and Glycemic Load” and “Learning About Glycemic Index and Glycemic Load.”
In this new study, 20 young people with Type 1 diabetes, age 7-16, were fed high-GI and low-GI meals on different days. The study participants, who all controlled their diabetes with basal-bolus insulin regimens (using either an insulin pump or injections), had their blood glucose levels recorded by a continuous glucose monitor. The participants’ diets were designed to contain a similar number of calories and macronutrients (carbohydrate, fat, and protein); however, the high-GI meals consisted of foods with higher GI values (such as corn flakes, white bread, and mashed potatoes) and had an average GI of 64, while the low-GI meals consisted of lower-GI foods (such as peaches, kidney beans, and brown basmati rice) and had an average GI of 40. (You can view both of the menus that were used here.)
At the end of the experiment, the researchers found that the participants’ blood glucose levels were in their target range 66% of the time when they were eating low-GI meals but only 47% of the time when eating high-GI meals—a significant difference. Participants also had lower daytime average blood glucose levels when they consumed the low-GI diet and needed to take less insulin. There were more episodes of mild hypoglycemia when participants were eating low-GI, however.
The researchers concluded that a low-GI diet may help children and adolescents with Type 1 diabetes significantly improve their blood glucose control and also reduce the amount of insulin they need to take over the long term. However, blood glucose would have to be carefully monitored and insulin doses adjusted in people adopting a low-GI diet to avoid hypoglycemia.