Evidence for a second meal cognitive effect: Glycaemic responses to high and low glycaemic index evening meals are associated with cognition the following morning
Institute of Psychological Sciences, University of Leeds, Lifton Palace Leeds, UK. Nutritional Neuroscience
(Impact Factor: 2.27).
03/2011; 14(2):66-71. DOI: 10.1179/1476830511Y.0000000002
Low glycaemic index (GI) foods consumed at breakfast can enhance memory in comparison to high-GI foods; however, the impact of evening meal GI manipulations on cognition the following morning remains unexplored. Fourteen healthy males consumed a high-GI evening meal or a low-GI evening meal in a counterbalanced order on two separate evenings. Memory and attention were assessed before and after a high-GI breakfast the following morning. The high-GI evening meal elicited significantly higher evening glycaemic responses than the low-GI evening meal. Verbal recall was better the morning following the high-GI evening meal compared to after the low-GI evening meal. In summary, the GI of the evening meal was associated with memory performance the next day, suggesting a second meal cognitive effect. The present findings imply that an overnight fast may not be sufficient to control for previous nutritional consumption.
Available from: Louise Dye
- "Typically, glucose levels will have returned to baseline at this late postprandial stage, however, hyperglycaemia induced by a high GL meal, is associated with other metabolic responses which potentially have a negative impact on cognitive function such as increased insulin and cortisol concentrations, oxidative stress, increased free fatty acids and increased inflammatory markers  . Furthermore, the second meal cognitive effect  indicates that GI/GL nutritional interventions may influence cognitive function substantially later than the immediate postprandial phase. The mechanisms which potentially underlie the association between IGT, obesity and cognitive impairment are discussed in detail elsewhere    and are beyond the scope of this paper. "
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ABSTRACT: Background and Aims
There has been no systematic investigation of the individual and combined effects of impaired glucose tolerance (IGT) and obesity on cognitive function in the absence of ageing. The aims were to examine the effects of IGT and increased waist circumference on cognitive function in ostensibly healthy adults, and to investigate whether a low glycaemic load (GL) breakfast can attenuate cognitive impairments in these populations.
Methods and Results
Sixty five females aged 30–50 years were classified into one of four groups following waist circumference (WC) measurements and an oral glucose tolerance test: NGT/low WC (n=25), NGT/high WC (n=22), IGT/low WC (n=9), IGT/high WC (n=9). Memory, psychomotor and executive functions were examined 30 and 120 minutes after consuming low GL, high GL and water breakfasts according to a randomised, crossover, counterbalanced design. IGT was associated with impairment of verbal and spatial memory, and psychomotor function relative to females with NGT, independent of waist circumference. Increased waist circumference was associated with impairment of verbal memory and executive function relative to females with low WC, independent of IGT. Consumption of the LGL breakfast attenuated verbal memory impairment in the IGT/high WC group relative to the HGL breakfast and no energy control.
Increased central adiposity and abnormalities in glucose tolerance preceding type 2 diabetes can have demonstrable negative effects on cognitive function, even in ostensibly healthy, middle-aged females. The potential for GL manipulations to modulate glycaemic response and cognitive function in type 2 diabetes and obesity merits further investigation.
- "Notwithstanding the OGTT, the procedure was identical for the IGT and type 2 diabetes studies. On the evening prior to the morning of all test days (including the OGTT) participants were required to eat a standard provided evening meal (Birdseye chicken and pasta ready meal containing 332 kcal, 37.6 g carbohydrate, 31.6 g protein and 6 g fat) between 18:00 and 21:00 h in order to control for any second meal cognitive effects . After the evening meal, only water consumption was permitted. "
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ABSTRACT: It has been established that type 2 diabetes, and to some extent, impaired glucose tolerance (IGT), are associated with general neuropsychological impairments in episodic memory. However, the effect of abnormalities in glucose metabolism on specific retrieval processes such as source monitoring has not been investigated. The primary aim was to investigate the impact of type 2 diabetes and IGT on simple word recognition (familiarity) and complex source monitoring (recollection). A secondary aim was to examine the effect of acute breakfast glycaemic load manipulations on episodic memory.
Data are presented from two separate studies; (i) 24 adults with type 2 diabetes and 12 controls aged 45-75years, (ii) 18 females with IGT and 47 female controls aged 30-50years. Controls were matched for age, IQ, BMI, waist circumference, and depression. Recognition of previously learned words and memory for specifically which list a previously learned word had appeared in (source monitoring) was examined at two test sessions during the morning after consumption of low glycaemic load, high glycaemic load and water breakfasts according to a counterbalanced, crossover design.
Type 2 diabetes (p<0.05) and IGT (p<0.01) were associated with significant source monitoring recollection deficits but not impairments in familiarity. Impairments were only observed in the late postprandial stage at the second test session. These impairments were not attenuated by the breakfast glycaemic load manipulations.
Isolated source monitoring recollection deficits indicate that abnormalities in glucose metabolism are not detrimental for global episodic memory processes. This enhances our understanding of how metabolic disorders are associated with memory impairments.
Available from: Samuele Cortese
- "Recent data in adults suggest that glycemic index of the evening meal may affect cognition in the following morning . In particular, high glycemic index dinner was associated with a better verbal recall 90 min after breakfast than a low glycemic index evening meal (Lamport et al., 2011). This effect was associated with increased blood glucose in the post-breakfast phase when a high glycemic index evening meal was consumed. "
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ABSTRACT: Skipping breakfast influences cognitive performance. The aim of our study was to investigate the relationship between the variation of hormonal and metabolic postprandial parameters induced by breakfast consumption or fasting and cognitive performance in obese children.
Cross-sectional study for repeated measures. Memory and attention assessment tests, hormones and nutrient oxidation were measured before and after consuming breakfast vs fasting in 10 prepubertal obese children.
Fasting induced a significant (P<0.05) increase of the Overall Index of the Continuous Performance Test II (a global index of inattention) and the Test of Memory and Learning Word Selective Reminding (a test of verbal memory), whereas no changes were found after breakfast. Fasting was associated with a reduction of insulin and an increase in glucagon, with no changes in glucose. The increase in inattention was associated with a reduction of carbohydrate oxidation (ρ=-0.66, P<0.05). We found no difference in the area under the curve of peptide YY and glucagon-like peptide-1 after breakfast or fasting, whereas Ghrelin was significantly lower. No association between postprandial hormone variation and cognitive performance was found.
Attention and visual memory performance in the morning were reduced when the children skipped breakfast. No association was found with hormones or metabolic changes, but we did find an association with a reduction of carbohydrate oxidation. Nevertheless, these preliminary findings need confirmation in larger sample size.
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