Abstract
Background: It is a commonly perceived perception that low-glycaemic index (GI) foods keep you feeling fuller for longer due to prolonged postprandial glycaemia (PPG). Thus, it is thought that low-GI foods could promote weight loss. However, the published findings on the relationship between PPG and satiety are inconclusive. Inconsistency in results could be attributable to factors in food other than the food’s glycaemic-inducing properties. For example, foods chosen on the basis of GI may also differ in factors such as palatability, macro- and micronutrient content, fibre and energy.
Objective: To determine the effect of PPG on satiety using sucrose (GI= 65) and isomaltulose (PalatinoseTM) (GI= 32) sweetened beverages. Sucrose and isomaltulose are both disaccharides comprising the monosaccharides glucose and fructose; both sugars are fully digested and absorbed; the difference between them being the glycosidic bond that is digested more rapidly for sucrose than it is for isomaltulose.
Design: Double-blinded, randomized controlled crossover trial, in which 77 participants were recruited to measure satiety outcomes, 12 of who volunteered for blood glucose measurements to determine glycaemic response.
Methods: Twelve volunteers were recruited for blood glucose measurements at baseline, 30, 60, 90, 120, 150, and 180-minutes after consumption of a sucrose or isomaltulose sweetened beverage, two weeks apart. Blood samples were analysed for blood glucose and insulin concentrations. The full 77 participants were randomized to receive one of each beverage, two weeks apart. Satiety was measured via visual analogue scales (VASs) at the same time points as the blood glucose measurements. VAS questions consisted of; “How hungry do you feel?”; “How satisfied do you feel?”; “How full do you feel?”; And “how much do you think you can eat?”. Weighed diet records were kept from 5:00pm (180-minutes after beverage consumption) until 12:00am, and were used to compare subsequent energy and macronutrient intake.
Results: Glycaemic and insulinaemic response, measured by incremental area under the curve (iAUC), differed significantly between the sucrose and isomaltulose beverages. Mean blood glucose concentrations differed by 44mmol/L (95% CI: -70, -18; P= 0.003) and mean blood insulin concentrations differed by 1883μIU/L (95% CI: -2846, 921; P= 0.001). VAS questions, measured by area under the cure (AUC), showed no difference in hunger (P= 0.699), satisfaction (P= 0.924), fullness (P= 0.780) or prospective food intake (P= 0.341), between the test beverages. No significant difference in subsequent energy (95% CI: -845, 267; P= 0.306), fat (95% CI: -13.3, 0.2; P= 0.056), protein (95% CI: -8.8, 4.3; P= 0.498) or carbohydrate intake (95% CI: -17.2, 20.5; P= 0.864) was found between the beverages.
Conclusion: There was no difference in measures of satiety following ingestion of sucrose and isomaltulose sweetened beverages despite differences in PPG. These findings indicate that at the differences in glycemic responses attained in this study, satiety is independent of glycaemia per se. Any differences found between foods chosen on the basis of GI could be attributable to food properties other than the glycaemic-inducing potential of the food.