Cognitive Performance Following Ingestion of Glucose–Fructose Sweeteners That Impart Different Postprandial Glycaemic Responses: A Randomised Control Trial

Abstract

We aimed to investigate the isolated effect of glycaemia on cognitive test performance by using beverages sweetened with two different glucose–fructose disaccharides, sucrose and isomaltulose. In a randomised crossover design, 70 healthy adults received a low-glycaemic-index (GI) isomaltulose and sucralose beverage (GI 32) and a high-GI sucrose beverage (GI 65) on two occasions that were separated by two weeks. Following beverage ingestion, declarative memory and immediate word recall were examined at 30, 80 and 130 min. At 140 min, executive function was tested. To confirm that the glycaemic response of the test beverages matched published GI estimates, a subsample (n = 12) of the cognitive testing population (n = 70) underwent glycaemic response testing on different test days. A significantly lower value of mean (95% CI) blood glucose concentration incremental area under the curve (iAUC) was found for isomaltulose, in comparison to the blood glucose concentration iAUC value for sucrose, the difference corresponding to −44 mmol/L∙min (−70, −18), p = 0.003. The mean (95% CI) difference in numbers of correct answers or words recalled between beverages at 30, 80 and 130 min were 0.1 (−0.2, 0.5), −0.3 (−0.8, 0.2) and 0.0 (−0.5, 0.5) for declarative memory, and −0.5 (−1.4, 0.3), 0.4 (−0.4, 1.3) and −0.4 (−1.1, 0.4) for immediate free word recall. At 140 min, the mean difference in the trail-making test between beverages was −0.3 sec (−6.9, 6.3). None of these differences were statistically or clinically significant. In summary, cognitive performance was unaffected by different glycaemic responses to beverages during the postprandial period of 140 min.

The effect of postprandial glycaemia on cognitive function – response to Young and Benton

“…In practice, people eat foods and meals with all of the attendant nutrient interactions and our study was designed as a practical experiment. Again though, in our previous study with sugar-sweetened beverages in which no nutrient interactions were present, there was no differential effect on cognitive performance following ingestion of the sucrose-and isomaltulose-sweetened beverages (3) .…”

“…The crossover design also addresses the comment regarding the vegan alternative.In practice, people eat foods and meals with all of the attendant nutrient interactions and our study was designed as a practical experiment. Again though, in our previous study with sugar-sweetened beverages in which no nutrient interactions were present, there was no differential effect on cognitive performance following ingestion of the sucrose-and isomaltulose-sweetened beverages (3) .The rationale for measuring cognitive outcomes over a 2-h period was explained in the Introduction of our article. The difference in glycaemic response to food is greatest during this time period allowing sufficient time for exogenous glucose to cross the blood-brain barrier (5) .…”

“…This study was designed as a practical experiment using the principle of replacing high-GI with low-GI ingredients as suggested by the Glycemic Index Foundation (2) . The relatively small difference in GI may have had an influence on the outcome, but we have also compared cognitive test scores to the same sugars ingested as sugar-sweetened beverages, thereby maximising the difference in GI between these sugars (33 GI units), and found no effect on cognitive outcomes (3) . Young and Benton suggest that we did not consider interpersonal variability in glycaemic response.…”

The effect on satiety of ingesting isosweet and isoenergetic sucrose- and isomaltulose-sweetened beverages: a randomised crossover trial

“…The beverages were matched for sweetness and immediate taste using a triangle sensory testing protocol prior to the laboratories, involving six people independent of the present study. Glycaemic and insulinaemic responses to the beverages were tested in twelve people to confirm between-drink differences in these factors; the results of these tests have been reported (11) . The mean published GI value of sucrose is 65 (SEM 4) (12) and of isomaltulose 32 (13) .…”