AN INSULIN INDEX OF FOODS - THE INSULIN DEMAND GENERATED BY 1000-KJ PORTIONS OF COMMON FOODS

The aim of this study was to systematically compare postprandial insul in responses to isoenergetic 1000-kJ (240-kcal) portions of several co mmon foods. Correlations with nutrient content were determined. Thirty -eight foods separated into six food categories (fruit, bakery product s, snacks, carbohydrate-rich foods, protein-rich foods, and breakfast cereals) were fed to groups of 11-13 healthy subjects. Finger-prick bl ood samples were obtained every 15 min over 120 min. An insulin score was calculated from the area under the insulin response curve for each food with use of white bread as the reference food (score = 100%). Si gnificant differences in insulin score were found both within and amon g the food categories and also among foods containing a similar amount of carbohydrate. Overall, glucose and insulin scores were highly corr elated (r = 0.70, P < 0.001, n = 38). However, protein-rich foods and bakery products (rich in fat and refined carbohydrate) elicited insuli n responses that were disproportionately higher than their glycemic re sponses. Total carbohydrate (r = 0.39, P < 0.05, n = 36) and sugar (r = 0.36, P < 0.05, n = 36) contents were positively related to the mean insulin scores, whereas fat (r = -0.27, NS, n = 36) and protein (r = -0.24, NS, n = 38) contents were negatively related. Consideration of insulin scores may be relevant to the dietary management and pathogene sis of non-insulin-dependent diabetes mellitus and hyperlipidemia and may help increase the accuracy of estimating preprandial insulin requi rements.