Glycemic Index of Some Traditional Fruits in Jamaica

Background: Fruits and vegetables, for their complex carbohydrates, dietary fiber and micronutrients, should form an essential part of every diet. In order to give good dietary advice to diabetic patients, it is necessary to know the glycemic index of foods commonly consumed locally. The objective of this study was to determine the glycemic index (GI) and glycemic load (GL) of commonly available and consumed June plum (Spondias dulcis), Otaheite apple (Syzygium malaccense), Pineapple (Ananas comosus), and Cucumber (Cucumis sativus) in Jamaica. Methods: Ten (10) healthy Jamaican subjects (5 males, 5 females) with mean age 30 ± 2 years and mean BMI 25 ± 1 kg/m2 were recruited to the study. Using a non-blind, crossover design trial, the subjects consumed 50 (or 25) grams of available carbohydrate portions of glucose (standard food) and test foods after an overnight fast. Their serum glucose levels were then determined at 0, 15, 30, 45, 60, 90 and 120 minutes after the consumption of each test food. Glucose was tested on three separate occasions, and the test foods once. The GI value was calculated geometrically by expressing the incremental area under the blood glucose curve (IAUC) for the test foods as a percentage of each subject's average IAUC for the standard food. Results: The results indicated that the IAUC for Pineapple (96 ± 15) and Otaheite apple (122 ± 29) were significantly higher (p < 0.05) than that of June plum (23 ± 6) and Cucumber (40 ± 14). Similarly the GI of Pineapple (80 ± 20) and Otaheite apple (64 ± 15) were significantly higher than June plum (13 ± 5) and Cucumber (21 ± 6). Conclusion: June plum, Cucumber, were shown to have low glycemic index values, whereas Otaheite apple was intermediate and Pineapple high.