Low glycaemic index and low glycaemic load diets may avert type 2 diabetes development: Study

The findings from the PURE study published in The Lancet Diabetes and Endocrinology suggest that consuming low GI and GL diets might prevent type 2 diabetes (T2D) development.

The glycemic index assigns a numeric score to a food based on how drastically it raises blood sugar. The foods are ranked on a scale of 0 to 100; pure glucose (sugar) has a value of 100. The lower the glycemic index of a food, the slower blood sugar rises after eating that food. The more processed a food is, the higher its GI, and the more fat or fiber in a food, the lower its GI. The glycaemic load rates carbohydrates according to the glycaemic index and the amount of carbohydrates in the food.

The association between the glycaemic load and glycaemic index with type 2 diabetes incidence is controversial. Therefore, Victoria Miller, Population Health Research Institute, McMaster University, Hamilton, ON, Canada, and colleagues aimed to evaluate this association in an international cohort with diverse glycaemic index and glycaemic load diets.

For this purpose, the researchers performed a prospective cohort study (PURE study) of 127 594 adults aged 35–70 years, from 20 high-income, middle-income, and low-income countries. Using country-specific validated food frequency questionnaires, they assessed diet at baseline using country-specific validated food frequency questionnaires.

The glycemic index and glycemic load were estimated based on the intake of seven categories of carbohydrate-containing foods. Participants were categorized into quintiles of GI and GL.

The study's primary outcome was incident type 2 diabetes. Multivariable Cox Frailty models with random intercepts for the study center were used to calculate hazard ratios (HRs).

The study led to the following findings:

· During a median follow-up of 11·8 years, 5·7% incident cases of type 2 diabetes occurred.

· In multivariable-adjusted analyses, a diet with a higher glycaemic index was significantly associated with a higher risk of diabetes (quintile 5 vs quintile 1; HR 1·15).

· Participants in the highest quintile of the glycaemic load had a higher risk of incident type 2 diabetes than those in the lowest quintile (HR 1·21).

· The glycaemic index was more strongly associated with diabetes among individuals with a higher BMI (quintile 5 versus quintile 1; HR 1·23) than those with a lower BMI (quintile 5 versus quintile 1; 1·10).

In conclusion, diets with a high GI and GL were associated with a higher risk of incident type 2 diabetes in the multinational cohort. The findings suggest that consuming low GI and GL diets might prevent diabetes development.

Reference:

Miller V, Jenkins DA, Dehghan M, Srichaikul K, Rangarajan S, Mente A, Mohan V, Swaminathan S, Ismail R, Luz Diaz M, Ravindran RM, Zatonska K, Bahonar A, Altuntas Y, Khatib R, Lopez-Jaramillo P, Yusufali A, Yeates K, Chifamba J, Iqbal R, Yusuf R, Catherina Swart E, Bo H, Han G, Li X, Alhabib KF, Rosengren A, Avezum A, Lanas F, Yusuf S; Prospective Urban and Rural Epidemiology (PURE) study investigators. Associations of the glycaemic index and the glycaemic load with risk of type 2 diabetes in 127 594 people from 20 countries (PURE): a prospective cohort study. Lancet Diabetes Endocrinol. 2024 Apr 5:S2213-8587(24)00069-X. doi: 10.1016/S2213-8587(24)00069-X. Epub ahead of print. PMID: 38588684.