Glycaemic index of selected staple carbohydrate-rich foods commonly consumed in Botswana

Objectives: Data on the glycaemic index (GI) of foods commonly consumed in Botswana are lacking. The present study aimed to evaluate the GI of some of the staple carbohydrate-rich foods eaten in Botswana. Design, setting and subjects: Fifty university student volunteers were divided into five groups. Members of each group consumed different test foods based on wheat, maize, sorghum, millet and morama beans to supply 50 g of available carbohydrate after 10-12 hours of overnight fasting. GI was determined using a standard method with white bread. Outcome measures: The GI values were calculated after measuring blood glucose levels before and after ingestion at 0, 15, 30, 45, 60, 90 and 120 minutes. Results: The results showed a clear variation in the GI values for the same food when consumed by different individuals. In addition, variations were observed in the GI values of test foods based on the same material. On average, wheat-based foods exhibited the highest GI values (103.1), followed by millet-based foods (95.3), sorghum-based foods (92.5), maize-based foods (9.1) and morama-based foods (86.4). Of the tested food, mapakiwa (wheat-based) had the highest GI (110.6) whereas roasted morama had the lowest GI (82.8). Conclusion: These results could form the basis of dietary advice to consumers, and particularly patients with diabetes. Further studies are needed on more of the commonly consumed foods in Botswana.