Comparison of Glycaemic Indices of Four Nigerian Staple Diets in Adult Male Wistar Rats

Abstract

The glycaemic indices (GI) of food paste made from wheat, corn, yam, flours and garri in apparently healthy rats using glucose as standard control and water as normal control were determined through  Laboratory-experimental design. This was achieved based on the effect of these different selected carbohydrate diets on postprandial glycaemia of the animal model which resulted on variable glucose response. The proximate analysis of the processed diet from wheat, corn and yam showed higher fat and protein contents than that of gari diet. Also, yam diet showed the lowest carbohydrate. The fibre content was shown to be higher in gari with the lowest in yam containing diet.  Each of these selected carbohydrate diets contained 56.85% starch. A total of eighteen (18) adult male wistar rats divided into six groups which consisted of three rats each were used in the course of this study. Animals were starved  throughout the night for twelve (12) hours and their blood glucose level tested at time zero, before the test food containing 2 grammes of carbohydrate per kilogramme body weight were cautiously administered. After a time interval of 15, 30, 45, 60, 90 and 120 minutes, the blood glucose was determined. α-amylase digestibility of the yam, corn, and wheat diets were higher than that of garri diet. The glycaemic index of yam diet (73.8%) was the highest, followed by that of corn diet (70.4%), wheat diet (70.2%) and garri (61.5%). The glycaemic indices of all the rat diets were less than that of the glucose standard (100%). Comparatively, the glycaemic indices of yam, wheat and corn diets did not differ significantly (p>0.05), while that of garri was significantly (p<0.05) lower.