Glycemic Index in the Development of Functional Beverage

Background: Due to the prevalence of diabetes in Jamaica, an understanding of the glycemic index (GI) and glycemic load (GL) values of beverages and food can aid dieticians in guiding consumers to choose sensibly. It is reported that consumption of low GI and GL foods may reduce the risk of type 2 diabetes, coronary heart disease and obesity. However, low GI snacks/food available to diabetic patients in Jamaica are very limited. This study was conducted to develop a low GI and GL vegetable drink that could be commercialized. Methods: Ten (10) healthy Jamaican subjects (5 males and 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 equicarbohydrate amounts (25 g of total available carbohydrate) of the vegetable (beetroot – Beta vulgaris, cucumber – Cucumis sativus and carrot – Daucus carota) drink and twice glucose as reference food (25 g of total carbohydrate). Blood glucose was determined after overnight fasting (0 hours) and at 15, 30, 45, 60, 90 and 120 minutes after the consumption of each test food. The glycemic index (GI) value was calculated geometrically by expressing the incremental area under the blood glucose curve (IAUC) as a percentage of each subject's average IAUC for the standard food. Results: The GI and GL values of the vegetable drink were found to be 34 ± 10 and 4.4, respectively. As per the Food and Agriculture Organization, GI cut-off values are as follows: low 70 and for GL, low ≤ 10, medium 10 to 20 or high ≥ 20. Hence the vegetable drink could be classified under low glycemic food/ nutrient. Conclusion: Identification of beverages and other foods with low glycemic responses may have practical applications in controlling blood glucose levels. This study provides scientific evidence of the blood glucose response of the formulated vegetable drink. The complex carbohydrates in beetroot, carrot and cucumber may be responsible for the low postprandial glycemic response. This will lead to a low demand for insulin secretion from the pancreatic β cells, which are often impaired in type 2 diabetic individuals.