The findings of an international study suggest that consuming low glycaemic index and low glycaemic load diets might prevent the development of type 2 diabetes. They also found a strong association between glycaemic index (GI) and the risk of type 2 diabetes among individuals with a higher Body Mass Index (BMI).
In a paper published in The Lancet Diabetes and Endocrinology last week, the authors showed a clear link between high GI and diabetes. The authors say: “The association between the glycaemic index and the glycaemic load [GL] with type 2 diabetes incidence is controversial.” They found that diets with a high GI and a high GL were associated with a higher risk of type 2 diabetes in the study that spanned five continents.
GI ranks carbohydrate-containing foods based on the blood glucose response, post-prandial or after a meal. The higher the blood sugar reading, the higher will be the GI. GL, on the other hand, is both the quality and quantity of carbohydrate in a specific food, and is the product of the GI and the amount of carbohydrate available in a serving.
One of the Indian authors of the paper, V. Mohan, founder, Madras Diabetes Research Foundation, tries to break it down: “It’s this question. If you continue to eat certain foods, will you develop diabetes?” Strangely enough, the concept of GI impacting diabetes has been controversial, and there has been little actual evidence applicable to a large population, he says.
“Our evidence shows that when you eat some foods, the blood sugar shoots up. How does it help? For persons with high BMI and a family history, better and nutritive food choices can put off the onset of diabetes. GL is also very important, because the quantity of low nutrition foods you eat also has an impact,” he explains.
A total of 1,27,594 adults aged 35–70 years without known diabetes from 20 high-income, middle-income, and low-income countries, had enrolled as part of the Prospective Urban and Rural Epidemiology (PURE) study. Their diet was assessed at baseline using country-specific food frequency questionnaires. The GI and GL were estimated on the basis of the intake of seven categories of carbohydrate-containing foods.
In the follow-up after nearly 12 years, 7,326 (5.7%) cases of type 2 diabetes occurred. A diet with a higher GI was significantly associated with a higher risk of diabetes. Participants in the highest quintile of the GL had a higher risk of incident type 2 diabetes compared with those in the lowest quintile. GI’s association with diabetes was stronger among individuals with a higher BMI than those with a lower BMI.
