Comparison of Glycemic Index of White Bread, Watermelon, Persian Melon, Grapes and Pears in NIDDM, IGT and Normal Subjects

The carbohydrate content in different foods may have different effects on postprandial blood glucose. Study was conducted to compare the glycemic effect of 50g carbohydrate in fruits (watermelon, Persian melon, grapes and pears) in normal, IGT and diabetic subjects. Thirty two subjects, 12 NIDDM, 12 IGT and 8 normals, with a mean age of 53±7 years were randomly selected. The subjects came to Varamin Health Centre 5 times in 2 to 4 days intervals. The subjects were divided in 5 group consumed one of the bread or fruit samples with 50g carbohydrate content. Blood samples were collected before and at 15, 30, 60, 120, 180 minutes after taking food. The blood glucose content was measured with autoanalyzer method. At the end of the experiment all the subjects received five different kinds of fruits or bread samples. The glycemic index of watermelon, Persian melon, grapes and pears were 47±22, 44 ±22, 47±26 and 43 ±22 respectively. No difference in glycemic index of different fruits was detected. Significant difference between glycemic index of diabetics and normal subjects was seen. A maximum and T maximum for bread, watermelon, melon, grapes and pears were 142±71, 83±50, 81±51, 78±48 and 75 ±58 mg/dl; and 50±18. 25±19, 35±22, 30±21, 27±20 minutes, respectively. White bread had later effect on rising blood glucose, but ultimately with a higher rate than fruits. The resutls of this study indicate that watermelon, Persian melon, grapes and pears have low glycemic index and can be recommended for use in diabetic meal plan.