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 with poor glucose regulation and poor cognition.


OBJECTIVE
The objective of this study was to determine 1) whether an association between cognition and glucose regulation is apparent in healthy seniors and 2) the effects of dietary carbohydrates on cognition.


METHODS
After an overnight fast, 10 men and 10 women (aged 60-82 y) consumed 50 g carbohydrate as glucose, potatoes, or barley or a placebo on 4 separate mornings. Cognitive tests were administered 15, 60, and 105 min after ingestion of the carbohydrate. Plasma glucose and serum insulin were measured.


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 cell function, high incremental area under the glucose curve, low insulin resistance, and low body mass index. The difference in plasma glucose after food consumption [glucose > potatoes > barley > placebo (P: < 0.03)] did not predict performance. Although overall performance did not differ with consumption of the different test foods, baseline score and beta cell function correlated with improvements in immediate and delayed paragraph recall for all 3 carbohydrates (compared with placebo); the poorer the baseline memory or 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 carbohydrates in visuomotor task performance but not on an attention task.


CONCLUSIONS
Glucose regulation was associated with cognitive performance in elderly subjects with normal glucose tolerance. Dietary carbohydrates (potatoes and barley) enhanced cognition in subjects with poor memories or beta cell function independently of plasma glucose.
Kaplan
R J
RJ
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada. randall.kaplan@utoronto.ca
Greenwood
C E
CE
Winocur
G
G
Wolever
T M
TM
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism / Q000523:psychology*; D001288:Attention / Q000187:drug effects / Q000502:physiology; D003071:Cognition / Q000187:drug effects* / Q000502:physiology*; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D004435:Eating / Q000502:physiology; D005260:Female; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology*; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000187:drug effects; D008875:Middle Aged; D011597:Psychomotor Performance / Q000187:drug effects / Q000502:physiology; D012016:Reference Values
D004040:Dietary Carbohydrates; D005947:Glucose