Cognitive performance is associated with glucose regulation in healthy elderly persons and can be enhanced with glucose and dietary carbohydrates

Background: A glucose drink has been shown to improve memory in persons wit h poor glucose regulation and poor cognition. Objective: The objective of this study was to determine 1) whether an assoc iation between cognition and glucose regulation is apparent in healthy seni ors and 2) the effects of dietary carbohydrates on cognition. Design: After an overnight fast, 10 men and 10 women (aged 60-82 y) consume d 50 g carbohydrate as glucose, potatoes, or barley or a placebo on 4 separ ate mornings, Cognitive tests were administered 15, 60, and 105 min after i ngestion of the carbohydrate. Plasma glucose and serum insulin were measure d. Results: In a multiple regression analysis, poor baseline (placebo) verbal declarative memory (immediate and 20-min delayed paragraph recall and word list recall) and visuomotor task performance were predicted by poor beta ce ll function, high incremental area under the glucose curve, low insulin res istance, and low body mass index. The difference in plasma glucose after fo od consumption [glucose > potatoes > barley > placebo (P < 0.03)] did not p redict performance. Although overall performance did not differ with consum ption of the different test foods, baseline score and beta cell function co rrelated with improvements in immediate and delayed paragraph recall for al l 3 carbohydrates (compared with placebo); the poorer the baseline memory o r beta cell function, the greater the improvement (correlation between beta cell function and improvement, in delayed paragraph recall: r > -0.50, P < 0.03). Poor beta cell function correlated with improvement for all carbohy drates in visuomotor task performance but not on an attention task. Conclusions: Glucose regulation was associated with cognitive performance i n elderly subjects with normal glucose tolerance. Dietary carbohydrates (po tatoes and barley) enhanced cognition in subjects with poor memories or bet a cell function independently of plasma glucose.