Animal studies have shown that there is a dose-response impact of glucose on memory but very few studies in humans have used several doses of glucose adjusted to body weight to determine whether there is more than one optimal dose. This study explored further the effect of ingested glucose on cognition in older adults by examining the impact of three doses of glucose (300 mg/kg, 650 mg/kg and 1 g/kg) on performance on neuropsychological tasks, including cognitive measures involving a concomitant or interference task. Another goal of this study was to investigate whether glucoregulation will mediate the impact of glucose on cognitive performance and if age will interact with this effect. A total of 103 older adults (mean age = 68.22) were tested twice, once after glucose ingestion and once after saccharin. Participants were categorized as younger (60-67) and older (68-85) and as better or worse glucoregulators. A doubly-multivariate analysis was conducted on 19 cognitive measures and only showed an overall significant effect of age. Some results suggest a small but not significant overall general decrease in performance on many tasks in people with worse glucoregulation. A number of methodological issues such as age and the generally high level of functioning of the participants may have reduced the ability of the present study to observe cognitive deficits or improvements.
