The effect of postprandial glycaemia on cognitive function: a randomised crossover trial

Glucoregulatory status modulates acute cognitive effects of repeated low-glycaemic snack consumption in older adults: a decentralized randomized controlled trial

PURPOSE

This study examined the effects of differential postprandial glucose responses on cognition in healthy older adults in a real-life setting. We hypothesised that consumption of a lower GI snack would have favourable effects on cognitive functioning and that this effect would be more pronounced in individuals with better glucoregulatory status.

METHODS

Twenty-eight healthy adults, aged 50-65 years, underwent two intervention periods of three consecutive test days, consuming either a low-GI snack or a control snack twice a day in a cross-over design. Cognitive performance and self-reported cognitive ability, mood, and appetite were measured six times on each of the six test days using a mobile application. Continuous glucose monitoring (CGM) occurred throughout the study. Glycated haemoglobin (HbA1c) and fasting glucose levels were taken as markers of glucoregulatory status.

RESULTS

Consumption of the low-GI snack led to blunted post-prandial glucose responses but did not affect cognitive functioning. Significant interactions between the snack effect and glucoregulatory status were observed for Spatial Memory (p < 0.01), Symbol Search (p < 0.05), Composite Cognition score (p < 0.05), and a trend for subjective cognitive ability (p = 0.07), indicating poorer effects of the low GI snack in subjects with poorer glucoregulation. Fluctuations in blood glucose parameters did not mediate the cognitive effects of the snacks or cognitive function fluctuations throughout the test days.

CONCLUSION

We demonstrated that poorer glucoregulatory status negatively affected the cognitive responses to a low-GI snack intervention. This interaction between glucoregulatory status and treatment response was detectable in non-diabetic subjects with normal to mildly compromised glucose regulation.

TRIAL REGISTRATION

NCT05801731, 24-03-2023.

Short-term effects of brief stair climbing interruptions on postprandial hyperglycemia during prolonged sitting: a randomized cross-over trial

Prolonged sitting can negatively impact postprandial glucose levels and cognitive function. While short bouts of stair climbing are thought to mitigate these risks, the findings remain inconclusive. The present study aimed to explore the effects of stair climbing bouts on postprandial glucose and cognitive functions during prolonged sitting. Twenty-eight sedentary young adults (aged 20-30 years) underwent two intervention visits after standardised lunch for two hours: (1) STAIR: the participants climbed two flight of stairs for two minutes every 30 min; (2) SIT: the participants continued to sit. Blood glucose was measured using capillary finger prick method while attention function was measured using computer-based cognitive tests at baseline, end of 1st hour and 2nd hour. Significant interaction (F2, 54 = 15.96, p < 0.001) was observed for conditions and time. During STAIR visit, significant changes in postprandial glucose at 1st hour (β = - 2.6 mmol/dl, p < 0.001) and 2nd hour (β = 3.0 mmol/dl, p < 0.001). No significant difference in the attention functions with time and conditions was observed. Stair climbing interruptions may serve as a feasible and effective countermeasure to high glycaemic variability or excursions that occur during prolonged sitting after postprandial hyperglycaemia.

Stair climbing interventions reduce postprandial hyperglycemia but not cognitive functions: findings of a randomized cross-over trial

Prolonged sitting can negatively impact postprandial glucose levels and cognitive functions. Stair climbing interventions have potential to mitigate these risks however remains unexplored. The present study aimed to explore the effects of stair climbing bouts on postprandial glucose and cognitive functions during prolonged sitting. Twenty-eight sedentary young adults (aged 20 - 30 years) underwent two intervention visits after standardized lunch for two hours: (1) STAIR: the participants climbed two flight of stairs for two minutes every 30 minutes; (2) SIT: the participants continued to sit. Blood glucose was measured using capillary finger prick method while attention function was measured using computer-based cognitive tests at baseline, end of 1st hour and 2nd hour. Significant interaction (F2, 54 = 15.96, p <0.001) was observed for conditions and time. During STAIR visit, significant changes in postprandial glucose at 1st hour (β = - 2.6 mmol/dl, p <0.001) and 2nd hour (β = 3.0 mmol/dl, p <0.001). No significant difference in the attention functions with time and conditions was observed. Stair climbing interruptions may be a promising solution to prevent high glycemic excursion occurring during prolonged sitting following postprandial sessions. However, the clinical benefits of stair climbing on attention functions remain unconvinced.

The impact of glycaemic load on cognitive performance: A meta-analysis and guiding principles for future research

The effect of breakfast glycaemic load (GL) on cognition was systematically examined. Randomised and non-randomised controlled trials were identified using PubMed, Scopus, and Cochrane Library (up to May 2022). 15 studies involving adults (aged 20 - 80 years) were included. Studies had a low risk, or some concerns, of bias. A random-effects meta-analysis model revealed no effect of GL on cognition up to 119 min post-consumption. However, after 120 min, immediate episodic memory scores were better following a low-GL compared to a high-GL (SMD = 0.16, 95% confidence interval [CI] = -0.00 to 0.32, p = 0.05, I2 = 5%). Subgroup analyses indicated that the benefit was greater in younger adults (<35 years) and those with better GT. A qualitative synthesis of 16 studies involving children and adolescents (aged 5 - 17 years) suggested that a low-GL breakfast may also benefit episodic memory and attention after 120 min. Methodological practises were identified which could explain a failure to detect benefits in some studies. Consequently, guiding principles were developed to optimise future study design.