Glycemic and Insulinemic Responses to Commonly Consumed Potatoes in Bangladeshi Type 2 Diabetic Subjects

Abstract

Glycemic indices (GIs) and insulin responses are useful for measuring biological effects and consequences of carbohydrates when designing healthy diets, particularly for people with or at risk of developing diabetes and others disorders such as metabolic syndrome. In this study, we investigated GIs and insulin (as measured by C-peptide) responses of patients with type 2 diabetes mellitus (T2DM) to Bangladeshi potatoes and sweet potatoes. Using a cross-over design, ten T2DM subjects consumed equivalent carbohydrate amounts (50 g of total carbohydrate) of either the vegetables or white bread (WB) (as reference food). Serum glucose levels were determined after 0, 15, 30, 45, 60, 90, 120, 150 and 180 minutes, and C-peptide levels were determined at 0 and 180 minutes. Glycemic Indices and Glycemic Loads (GLs) were calculated. Both plain and sweet potatoes showed a significantly higher serum glucose response compared to the reference food. The similar glycemic response between plain and sweet potatoes was reflected in their GI values: 162 ± 50 and 191 ± 66, respectively. The GL values were 8 and 11, respectively. The substantially higher glycemic response and GI values of the two potatoes were not the consequence of a suppressed insulin response. Compared to the mean values of the international table, Bangladeshi potatoes and sweet potatoes are very high GI foods. However, based on the dietary practices in our society, potatoes and sweet potatoes may be used as low and medium GL foods, respectively. This work may help create a better food exchange table for diabetic patients.