Dietary CHO assessment: GI food value and insulin response to selected carbohydrate rich products in typical Indian diet

Abstract

Glycemic and insulinemic responses to food may depend on several intrinsic factors such as the type of sugar, amylose: amylopectin ratio, molecular arrangement, size of starch granules, co-components such as moisture, fat, protein, fiber, as well as external factors like cooking or processing technique and total amount consumed. The Glycemic Index (GI) classification is applicable to equal quantities of available carbohydrates only, whereas in practical situation we consume whole foods and not just the carbohydrate component. The postprandial effect of quality and quantity of dietary carbohydrate consumed as food, not as nutrient, is studied using Glycemic Indexfood (GIfood). Postprandial glycemic response to whole foods are compared on equi-quantity basis with white bread (standard) giving the Glycemic Bread Equivalents (GBE). The GIfood values for specific quantity (e.g. 50g) of test foods depict the Relative Glycemic Impact (i.e. GBE/50g of food) and GIfood values for 100g food portions represent the Relative Glycemic Potency (i.e. GBE/100g of food). The incremental area under the curve (IAUC) for blood glucose and insulin level at fasting, and at every ½ h (30, 60, 90 and 120 min) upto 2 h after consumption of different doses (50 and 100g) of carbohydrate rich foods, frequently consumed in India, like Chapatti, Thepla, Marie biscuit, Vada Pav, boiled white Rice, Puffed Rice, Rice Kheer, Potato and Sago Khichdi were compared with that of standard food, white bread. The GIfood value for 50g (GBE/50g) portion of test food was highest for Puffed Rice (89 ± 53.4), followed by Chapatti (44 ± 34.5), Marie Biscuit (44 ± 30.9), Vada pav (43.8 ± 13.5), Potato (32 ± 11.8), Sago Khichdi (26 ± 12.8), and much lower for Thepla (17 ± 6.4), Rice (11 ± 10.8) and even for the sweet dish Rice Kheer (19 ± 13.2). With an increase in food load to 100g (GBE/100g), the same trend was observed, though the values did not increase in a mathematically proportional rate.