Glycemic Indices of Multiple Oral Nutritional Supplements: A Randomized Cross-Over Study in Indian Adults

Abstract

Background: A randomized cross-over study was conducted to assess the glycemic index (GI) of seven Oral Nutritional Supplements (ONSs). These ONSs are designed to support the nutritional requirements of different age-groups, physiological states, or health conditions among Indian adults. Methods: The study had two phases viz., phase1 (n = 18) studied two ONSs: A1 and B1 and phase 2 (n = 20) studied five ONSs: A2, B2, C2, D2 & E2. The subjects were healthy, non-diabetic adults, aged between 20 - 44 years with a mean Body Mass Index of 21.2 ± 1.52 kg/m2 (Phase 1) and 21.0 ± 1.45 kg/m2 (Phase 2). All these ONSs were compared with reference drinks (glucose). The carbohydrates in one serving of each ONS were matched to carbohydrates from 25 grams of glucose following ISO 2010 guidelines. Capillary blood was assessed for blood glucose response at baseline, 15, 30, 45, 60, 90 and 120 minutes. GI was calculated as the incremental area under the curve (iAUC) for the test drinks and expressed as a percentage of the average iAUC from glucose. Results: Phase 1 indicated that the high fiber diabetes-specific nutrition supplement A1 with higher protein (23% energy), higher fat (25% energy) and reduced carbohydrates (40% energy) had a significantly (p = 0.002) lower GI [34 (±6)] as compared to B1 [63 (±7)] (protein 19%, fat 7% and carbohydrates 60% energy) even with similar amount (22%) and type of fiber. Phase 2 reported that all test products [A2 (32 ± 5), B2 (37 ± 4), C2 (31 ± 5), D2 (31 ± 5) and E2 (55 ± 4)] had a low GI. As compared to phase 1, ONSs in phase 2 had lower fiber content (1.6% - 4.6% energy). Conclusion: The glycemic index of oral nutrition supplements is influenced not only by their fiber content, but also by the overall macronutrient composition including protein (≥17% energy), fat (≥10% - 27% energy) and carbohydrates (40% - 57.5% energy).