title: Glucose facilitation of cognitive performance in healthy young adults: examination of the influence of fast-duration, time of day and pre-consumption plasma glucose levels Glycaemic index and glycaemic load of breakfast predict cognitive function and mood in school children: a randomised controlled trial. Glycemic index of foods: a physiological basis for carbohydrate exchange. Brief fasting, stress, and cognition in children. Effects on cognitive performance of modulating the postprandial blood glucose profile at breakfast Breakfast reduces declines in attention and memory over the morning in schoolchildren Ingesting breakfast meals of different glycaemic load does not alter cognition and satiety in children Breakfast glycaemic index and exercise: Combined effects on adolescents' cognition The delivery rate of dietary carbohydrates affects cognitive performance in both rats and humans The influence on cognition of the interaction between the macro-nutrient content of breakfast and glucose tolerance Blood glucose influences memory and attention in young adults
abstract: Abstract . Rationale : Previous investigations have demonstrated increased performance after the administration of a glucose-load on certain aspects of cognitive functioning in healthy young adults . Generally these studies have used a procedure where participants were tested in the morning after an overnight fast . Objective : The aim of the present study was , for the first time , to investigate the glucose cognitive facilitation effect under more natural testing times and with shorter duration of the previous fast . Methods : Measures of verbal and non-verbal memory performance were compared under different fasting intervals ( 2-h fast versus overnight fast ) , times ( morning versus afternoon ) and glycaemic conditions ( glucose versus aspartame drinks ) in healthy young participants . Results : There was a significant glucose facilitation effect on long-term verbal memory performance . In addition , glucose significantly enhanced long-term spatial memory performance . The effect of glucose was essentially equivalent whether it was given after an overnight fast or a 2-h fast following breakfast or lunch . There was no effect of drink and time of day on working memory performance . Conclusions : The results of this study further support the hypothesis that glucose administration can enhance certain aspects of memory performance in healthy young adults . More significantly , the findings indicate that this cognitive facilitation effect persists under more naturalistic conditions of glucose administration and is not restricted to long fast duration s or morning administration The macronutrient composition of a breakfast that could facilitate performance after an overnight fast remains unclear . As glucose is the brain 's major energy source , the interest is in investigating meals differing in their blood glucose-raising potential . Findings vary due to unaccounted differences in glucoregulation , arousal and cortisol secretion . We investigated the effects of meals differing in glycaemic index ( GI ) and glycaemic load ( GL ) on cognition and mood in school children . A total of seventy-four school children were matched and r and omly allocated either to the  high-GL or low-GL  group . Within each GL group , children received high-GI and low-GI breakfasts .  Cognitive function ( CF ) and mood were measured 95 - 140 min after breakfast . Blood glucose and salivary cortisol were measured at baseline , before and after the CF tests . Repeated- measures ANOVA was used to identify differences in CF , mood , glucose and cortisol levels between the breakfasts . Low-GI meals predicted feeling more alert and happy , and less nervous and thirsty ( P < 0·05 for each ) ; high-GL meals predicted feeling more confident , and less sluggish , hungry and thirsty ( P < 0·05 for each ) . High-GL ( P < 0·001 ) and high-GI ( P = 0·05 ) meals increased glucose levels 90 min after breakfast , and high-GI meals increased cortisol levels ( P < 0·01 ) . When baseline mood , glucose and cortisol levels were considered , low-GI meals predicted better declarative-verbal memory ( P = 0·03 ) , and high-GI meals better vigilance ( P < 0·03 ) ; observed GI effects were valid across GL groups . GI effects on cognition appear to be domain specific . On balance , it would appear that the low-GI high-GL breakfast may help to improve learning , and of potential value in informing government education policies relating to dietary recommendations and implementation concerning breakfast The determine the effect of different foods on the blood glucose , 62 commonly eaten foods and sugars were fed individually to groups of 5 to 10 healthy fasting volunteers .  Blood glucose levels were measured over 2 h , and expressed as a percentage of the area under the glucose response curve when the same amount of carbohydrate was taken as glucose . The largest rises were seen with vegetables ( 70 + /- 5 % ) , followed by breakfast cereals ( 65 + /- 5 % ) , cereals and biscuits ( 60 + /- 3 % ) , fruit ( 50 + /- 5 % ) , dairy products ( 35 + /- 1 % ) , and dried legumes ( 31 + /- 3 % ) . A significant negative relationship was seen between fat ( p less than 0.01 ) and protein ( p less than 0.001 ) and postpr and ial glucose rise but not with fiber or sugar content Effects of skipping breakfast on speed and accuracy of response in a number of problem solving tasks were assessed in 9- to 11-yr-old , well-nourished children . The conceptual framework for this study was derived from an experimental model of the effects of mild environmental stress , e.g. , noise , on human performance . Plasma glucose , beta-hydroxybutyrate , lactate , and free fatty acids were used as indicators of the induced metabolic stress , and the extent of their association with the behavioral measures was determined . Fasting had an adverse effect on the accuracy of responses in problem solving , but it had a beneficial effect on immediate recall in short-term memory . Both effects are explained by a heightened arousal level associated with the brief experimental fast Background / Objectives : Considering the importance of glucose as a brain substrate , the postpr and ial rate of glucose delivery to the blood could be expected to affect cognitive functions . The purpose was to evaluate to what extent the rate of glucose absorption affected measures of cognitive performance in the postpr and ial period . In addition , cognitive performance was evaluated in relation to individual glucoregulation . Subjects/ Methods : A white wheat bread ( WWB ) enriched with guar gum ( G-WWB ) with the capacity to produce a low but sustained blood glucose net increment was developed . The G-WWB was evaluated in the postpr and ial period after breakfast with respect to effects on cognitive function ( working memory and selective attention ( SA ) ) in 40 healthy adults ( 49–71 years , body mass index 20–29 kg/m2 ) , using a high glycaemic index WWB for comparison in a r and omised crossover design . Results : The G-WWB improved outcome in the cognitive tests ( SA test ) in the later postpr and ial period ( 75–225 min ) in comparison with the WWB ( P<0.01 ) . Subjects with better glucoregulation performed superior in cognitive tests compared with subjects with worse glucoregulation ( P<0.05 ) . Conclusions : Beneficial effects on cognitive performance were observed with the G-WWB in the late postpr and ial period . The positive effect is suggested to emanate from improved insulin sensitivity , possibly in a combination with an enhanced neural energy supply . The results highlight the importance of carbohydrate foods that induces a low but sustained blood glucose profile in enhancing postpr and ial cognitive functions Twenty-nine schoolchildren were tested throughout the morning on 4 successive days , having a different breakfast each day ( either of the cereals Cheerios or Shreddies , glucose drink or No breakfast ) . A series of computerised tests of attention , working memory and episodic secondary memory was conducted prior to breakfast and again 30 , 90 , 150 and 210 min later . The glucose drink and No breakfast conditions were followed by declines in attention and memory , but the declines were significantly reduced in the two cereal conditions . This study provides objective evidence that a typical breakfast of cereal rich in complex carbohydrates can help maintain mental performance over the morning Background / Objectives : The effect of Glycaemic Index ( GI ) and Load ( GL ) of breakfasts on satiety and aspects of cognitive function in children is inconclusive . We aim ed to assess if isocaloric breakfasts differing in GL ( by replacing high-GI carbohydrate foods with dairy protein foods ) acutely alter cognitive function and satiety in 10- to 12-year-old children . Subjects/ Methods : A total of 39 children , aged 11.6±0.7 years with body mass index 18.9±3.0 kg/m2 ( Mean±s.e . ) participated in a r and omised crossover trial of three isocaloric breakfasts ( 1.3 MJ ) : high GL ( HGL : 7 g protein , 9 g fat , 50 g carbohydrate , GL 33 ) ; medium GL ( MGL : 14 g protein , 9 g fat , 45 g carbohydrate , GL 24 ) and low GL ( LGL : 18 g protein , 10 g fat , 38 g carbohydrate , GL 18 ) . Blood glucose was recorded using a continuous glucose monitor . Subjective hunger and cognitive performance were measured before and hourly after consuming the test breakfast via a computer-delivered battery . Ad libitum intake at a buffet lunch meal was measured at 3 h at the end of testing . Results : Incremental area under the glucose curve ( iAUC ) was significantly different with HGL > MGL > LGL ( P<0.001 ) . Glucose concentrations fell below baseline after 83±6 min for HGL , 63±5 min ( MGL ) and 67±5 min (LGL)(P=0.009 ) . Breakfast GL did not significantly alter changes in cognitive function or self-reported satiety throughout testing . Energy intake at lunch was not significantly different between treatments ( HGL 2943±168 kJ ; MGL 2949±166 kJ ; LGL 2993±191 kJ ) . Conclusions : Reducing breakfast GL by replacing carbohydrate with protein does not alter satiety or cognition over 3 h in 10- to 12-year-old children The aim of the present study was to examine the combined effects of breakfast glycaemic index ( GI ) and a mid-morning bout of exercise on  adolescents ' cognitive function . Participants were r and omly allocated to a high or low GI breakfast group in a mixed research design , where each participant completed two experimental trials ( exercise and resting ) . Forty-two adolescents ( 12.4±0.5 years old ) , undertook a bout of exercise ( ten repeats of level one of the multi-stage fitness test ; exercise trial ) or continued to rest ( resting trial ) following consumption of either a high or low GI breakfast . A battery of cognitive function tests ( visual search test , Stroop test and Sternberg paradigm ) was completed 30 min before and 45 min following the  exercise . Average heart rate during exercise was 170±15 beats·min(-1 ) . On the complex level of the Stroop test , response times improved across the morning following the low GI breakfast on both the exercise and resting trials , though the improvement was greatest on the exercise trial . However , response times only improved on the resting trial following the high GI breakfast ( p=0.012 ) . On the 5 letter level of the Sternberg paradigm , response times improved across the morning following the low GI breakfast ( regardless of exercise ) and only on the exercise trial following the high GI breakfast ( p=0.019 ) . The findings of the present study suggest that the combined effects of breakfast GI and exercise in adolescents depend upon the component of cognitive function examined . A low GI breakfast and mid-morning bout of exercise were individually beneficial for response times on the Sternberg paradigm , whereas they conferred additional benefits for response times on the Stroop test Rationale . Glucose is the main metabolic fuel of the brain . The rate of glucose delivery from food to the bloodstream depends on the nature of carbohydrates in the diet , which can be summarized as the glycaemic index ( GI ) . Objectives . To assess the benefit of a low versus high GI breakfast on cognitive performances within the following 4 h. Methods . The influence of the GI of the breakfast on verbal memory of young adults was measured throughout the morning in parallel to the assessment of blood glucose levels . The learning abilities of rats performing an operant-conditioning test 3 h after a breakfast-like meal of various GI was also examined . Results . A low GI rather than high GI diet improved memory in humans , especially in the late morning ( 150 and 210 min after breakfast ) . Similarly , rats displayed better learning performance 180 min after they were fed with a low rather than high GI diet . Conclusion . Although performances appeared to be only remotely related to blood glucose , our data provide evidence that a low GI breakfast allows better cognitive performances later in the morning Previously it has been found that both missing breakfast and having poorer glucose tolerance were associated with better memory . The present study therefore examined the impact of eight breakfasts , in a factorial design , that contained either high or low levels of carbohydrate , fat or protein . The meals were design ed to vary the rate of release of glucose into the blood stream . Memory , reaction times and vigilance were assessed 30 , 75 and 120 min following breakfast . Using fasting blood glucose levels as a measure of glucose tolerance , better memory was found to be associated with better glucose tolerance and the consumption of meals that more slowly release glucose into the blood . The effects of the meals on reaction times and vigilance were opposite to those with memory in that higher levels of blood glucose tended to be associated with better performance . It was concluded that individual differences in glucose tolerance interact with the glycaemic load of a meal to influence cognitive functioning There is evidence from animal studies that increased blood glucose levels are associated with improved memory and attention . Although previous studies have found human memory to be facilitated by the administration of glucose , attentional measures have been largely ignored . Therefore the impact of a glucose drink , or a placebo , on the Rapid Information Processing Task and the Stroop Task was examined . The reaction times of those taking the Rapid Information Processing Task were faster both during the baseline period and after a glucose drink if the blood glucose values were high . With the  Stroop task  the ability to perform the most cognitively dem and ing sub-test was selectively enhanced if blood glucose values were increasing prior to starting the test . The ability to recall words from a word list was greater if a glucose drink had been consumed , although primary and recency were not differentially influenced . The possibility is discussed that higher levels of brain glucose are associated with better memory and attention
target: In summary , GI breakfasts do not affect cognitive domains in children and adolescents
background: This systematic review and meta- analysis aims to compare the effect of High-Glycemic Index ( GI ) versus Low-GI breakfasts on cognitive functions , including memory and attention , of children and adolescents .