Breakfast glycaemic index and exercise: Combined effects on adolescents' cognition Glycaemic index and glycaemic load of breakfast predict cognitive function and mood in school children: a randomised controlled trial. The delivery rate of dietary carbohydrates affects cognitive performance in both rats and humans Postprandial Effects of Breakfast Glycemic Index on Vascular Function among Young Healthy Adults: A Crossover Clinical Trial Second-meal effect: low-glycemic-index foods eaten at dinner improve subsequent breakfast glycemic response. Dietary fiber, glycemic index, glycemic load and renal cell carcinoma risk. Prolongation of satiety after low versus moderately high glycemic index meals in obese adolescents. Low glycemic index breakfasts and reduced food intake in preadolescent children. Four-week low-glycemic index breakfast with a modest amount of soluble fibers in type 2 diabetic men. Effects of long-term intervention with low- and high-glycaemic-index breakfasts on food intake in children aged 8-11 years. Dietary fiber, whole grains, carbohydrate, glycemic index, and glycemic load in relation to risk of prostate cancer
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 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 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 This study aim ed to evaluate the postpr and ial effects of high and low glycemic index ( GI ) breakfasts on vascular function . It was a crossover trial that included 40 young healthy adults ( 50 % women ) , aged 20–40 years , who were recruited at primary care setting s. They consumed three experimental breakfasts in r and omized order , each one separated by a 1-week washout period : ( 1 ) control conditions ( only water ) ; ( 2 ) low GI ( LGI ) breakfast ( 29.4 GI and 1489 KJ energy ) ; and ( 3 ) high GI ( HGI ) breakfast ( 64.0 GI and 1318 KJ energy ) . Blood sample s were collected at 60 and 120 min after each breakfast to determine glucose and insulin levels . Vascular parameters were measured at 15 min intervals . Augmentation index ( AIx ) was studied as a primary outcome . Secondary outcomes comprised glucose , insulin , heart rate ( HR ) and pulse pressures ( PPs ) . We found a trend toward increased AIx , HR and PPs for the HGI versus the LGI breakfast . A significant interaction between the type of breakfast consumed and all measured parameters was identified ( p < 0.05 ) except for central PP . Stratifying data by sex , this interaction remained significant for AIx and augmentation pressure only in males ( p < 0.05 ) . In conclusion , breakfast GI could affect postpr and ial vascular responses in young healthy adults The effects of the glycemic index ( GI ) of carbohydrate eaten the previous night on the glycemic response to a st and ard test meal eaten subsequently in the morning ( breakfast ) was studied . On separate evenings normal subjects ate low- or high-GI test meals of the same nutrient composition . The dinners consisted of single foods in two experiments and mixed meals containing several foods in the third . The differences between the observed glycemic responses to low- and high-GI dinners were predicted by their GIs . The glycemic responses to breakfast were significantly lower on mornings after low-GI dinners than after high-GI dinners . Eating , at dinner , foods with different fiber contents but the same GI had no effect on postbreakfast glycemia . We conclude that the GI predicts the difference between glycemic responses of mixed dinner meals ; breakfast carbohydrate tolerance is improved when low-GI foods are eaten the previous evening Several epidemiological studies have investigated the potential association between dietary fiber , glycemic index ( GI ) or glycemic load ( GL ) , and renal cell carcinoma ( RCC ) risk with inconsistent results . The aim of this study was to systematic ally evaluate this issue with a meta- analysis approach . A comprehensive literature search up to March 2018 was performed in PubMed and Web of Science data bases . Summary relative risks ( RRs ) and 95 % confidence intervals ( CIs ) were estimated with a r and om-effects model . Twelve studies were finally included in this study ( eight for fiber analysis , five for GI and five for GL ) . A significant positive association was observed between GI and the risk of RCC ( summary RR 1.16 , 95 % CI 1.02 - 1.32 ) , and no significant heterogeneity was detected among studies ( I2 = 22.8 % , P = 0.262 ) . A significant inverse association was found between fiber intake and the risk of RCC ( summary RR 0.82 , 95 % CI 0.72 - 0.92 ) , and no significant heterogeneity was observed across studies ( I2 = 27.6 % , P = 0.218 ) . GL was not significantly associated with RCC risk ( summary RR 1.14 , 95 % CI 0.81 - 1.60 ) , and significant heterogeneity was found across studies ( I2 = 78.6 % , P < 0.001 ) . In conclusion , this systematic review and meta- analysis suggests that dietary GI and fiber may be associated with the risk of RCC . Further large prospect i ve cohort studies are still warranted to confirm our preliminary findings BACKGROUND One in 5 American children is overweight , despite a decrease in total fat consumption . This has sparked an interest in the carbohydrate composition of diets , including the glycemic index ( GI ) . OBJECTIVE To investigate whether a low-GI meal replacement ( LMR ) produced similar metabolic , hormonal , and satiety responses in overweight adolescents as a low-GI whole-food meal ( LWM ) when compared with a moderately high-GI meal replacement ( HMR ) . METHODS R and omized , crossover study comparing LMR , HMR , and LWM in 16 ( 8 male/8 female ) adolescents during 3 separate 24-hour admissions . The meal replacements consisted of a shake and a nutrition bar . Identical test meals were provided at breakfast and lunch . Metabolic and hormonal indices were assessed between meals . Measures of participants ' perceived satiety included hunger scales and ad libitum food intake . RESULTS The incremental areas under the curve for glucose were 46 % and 43 % lower after the LMR and LWM , respectively , compared with the HMR .  Insulin 's incremental area under the curve was also significantly lower after both low GI test meals ( LMR = 36 % ; LWM = 51 % ) compared with the HMR .  Additional food was requested earlier after the HMR than the LMR ( 3.1 vs 3.9 hours , respectively ) , although voluntary energy intake did not differ . CONCLUSIONS Differences in insulin response between the meal replacements occurred , and prolongation of satiety after the LMR , based on time to request additional food , was observed . We speculate that the prolonged satiety associated with low GI foods may prove an effective method for reducing caloric intake and achieving long-term weight control OBJECTIVE Recent reports have suggested that a low glycemic index ( GI ) diet may have a role in the management of obesity through its ability to increase the satiety value of food and modulate appetite . To date , no long-term clinical trials have examined the effect of dietary GI on body weight regulation . The majority of evidence comes from single-day studies , most of which have been conducted in adults . The purpose of this study was to investigate the effect of 3 test breakfasts-low-GI , low-GI with 10 % added sucrose , and high-GI-on  ad libitum lunch intake , appetite , and satiety and to compare these with baseline values when habitual breakfast was consumed . METHODS A 3-way crossover study using block r and omization of breakfast type was conducted in a school that already ran a breakfast club . A total of 37 children aged 9 to 12 years ( 15 boys and 22 girls ) completed the study . The proportion of nonoverweight to overweight/obese children was 70:30 . Children were divided into 5 groups , and a rolling program was devised whereby , week by week , each group would r and omly receive 1 of 3 test breakfasts for 3 consecutive days , with a minimum of 5 weeks between the test breakfasts . Participants acted as their own control . The 3 test breakfasts were devised to match the energy and nutritional content of an individual 's habitual breakfast as far as possible . All test breakfasts were composed of fruit juice , cereal , and milk with/without bread and margarine ; foods with an appropriate GI value were selected . After each test breakfast , children were instructed not to eat or drink anything until lunchtime , except water and a small serving of fruit supplying approximately 10 g of carbohydrate , which was provided . Breakfast palatability , satiation after breakfast , and satiety before lunch were measured using rating scales based on previously used tools . Lunch was a buffet-style meal , and children were allowed free access to a range of foods . Lunch was served in the school hall where the rest of the schoolchildren were eating . Food intake at lunch was unobtrusively observed and recorded . Leftovers and food swapping were recorded , and plate waste was estimated . Lunch intakes were analyzed using a multilevel regression model for repeated measures data . The likelihood ratio statistic was used to determine whether the type of breakfast eaten had a significant effect on lunch intake after allowing for sex and weight status . RESULTS The type of breakfast eaten had a statistically significant effect on mean energy intake at lunchtime : lunch intake was lower after low-GI and low-GI with added sucrose breakfasts compared with lunch intake after high-GI and habitual breakfasts ( which were high-GI ) . Overweight and sex did not have a significant effect on lunch intake . Pairwise comparisons among the 3 types of test breakfasts and between each test breakfast and habitual breakfast were made . Lunch intake after the high-GI breakfast was significantly higher than after the low-GI breakfast and low-GI breakfast with added sucrose . The details of the pairwise comparisons were as follows : high-GI versus low-GI = 145 + /- 54 kcal ; high-GI versus low-GI plus sucrose = 119 + /- 53 kcal ; low-GI plus sucrose versus low-GI = 27 + /- 54 kcal . Lunch intake after the low-GI breakfast and the low-GI breakfast with added sucrose was significantly lower than after the habitual breakfast . The details of the pairwise comparisons were as follows : low-GI versus habitual = -109 + /- 75 kcal ; low-GI plus sucrose versus habitual = -83 + /- 75 kcal ; high-GI versus habitual = 36 + /- 75 kcal . There were no significant differences between the test breakfasts in immediate satiation . The high-GI breakfasts were rated to be more palatable than the low-GI breakfasts . At lunchtime , hunger ratings were greater after the high-GI breakfast compared with the other 2 test breakfasts on 2 of the 3 experimental days . Prelunch satiety scales were inversely related to subsequent food intake . CONCLUSIONS These results suggest that low-GI foods eaten at breakfast have a significant impact on food intake at lunch . This is the first study to observe such an effect in a group of normal and overweight children and adds to the growing body of evidence that low-GI foods may have an important role in weight control and obesity management . The potentially confounding effect of differences in the macronutrient and dietary fiber content of the test breakfasts warrants additional study . In addition , the impact of GI on food intake and body weight regulation in the long term needs to be investigated Low-glycemic index diets are associated with a wide range of benefits when followed on a chronic basis . The chronic effects , however , of the substitution of 1 meal per day are not well known in diabetic subjects . Therefore , we aim ed to evaluate whether the chronic use of a low-glycemic index breakfast ( low-GIB ) rich in low-GI carbohydrates and a modest amount of soluble fibers could have an effect on lipemia at a subsequent lunch , and improve glucose and lipid metabolism in men with type 2 diabetes . A total of 13 men with type 2 diabetes were r and omly allocated in a double-blind cross-over design to a 4-week daily intake of a low-GI versus a high-GI breakfast separated by a 15-day washout interval . The low-GI breakfast was composed of whole grain bread and muesli containing 3 g beta-glucan from oats . Low-GIB induced lower postpr and ial plasma glucose peaks than the high-GIB at the beginning ( baseline , P < .001 ) and after the 4-week intake ( P < .001 ) . The incremental area under the plasma glucose curve was also lower ( P < .001 , P < .01 , baseline , and 4 weeks , respectively ) . There was no effect on fasting plasma glucose , insulin , fructosamine , or glycosylated hemoglobin ( HbA(1c ) ) . Fasting plasma cholesterol , as well as the incremental area under the cholesterol curve , were lower ( P < .03 , P < .02 ) after the 4-week low-GIB period than after the high-GIB period . Apolipoprotein B ( apo B ) was also decreased by the 4-week low-GIB . There was no effect of the low-GI breakfast on triacylglycerol excursions or glucose and insulin responses at the second meal . The high-GIB , however , tended to decrease the amount of mRNA of leptin in abdominal adipose tissue , but had no effect on peroxisome proliferator-activated receptor gamma ( PPARgamma ) and cholesterylester transfer protein ( CETP ) mRNA amounts . In conclusion , the intake of a low-GI breakfast containing a modest amount ( 3 g ) of beta-glucan for 4 weeks allowed good glycemic control and induced low plasma cholesterol levels in men with type 2 diabetes . The decrease in plasma cholesterol associated with low-GI breakfast intake may reduce the risk of developing cardiovascular complications in subjects with type 2 diabetes The aim of the present study was to investigate the effects of long-term intervention of low-glycaemic-index ( GI ) v. high-GI breakfasts on energy and macronutrient intakes in children aged 8 - 11 years . Preadolescent children were assigned to one of two groups in a r and om cross-over design . Each group was given low-GI and high-GI breakfasts on two non-consecutive days per week for 10 weeks per breakfast type . Each breakfast provided approximately 1273 kJ ( 300 kcal ) and was closely matched for macronutrient and dietary fibre content . Subsequent food intake at an ad libitum buffet lunch was recorded and daily energy and macronutrient intakes were measured by 24 h recall and 3 d food diaries . There was a tendency towards a reduced energy intake at lunch following the low-GI breakfast compared with the high-GI breakfast , although the mean difference of 75 kJ ( 18 kcal ) was not significant ( P = 0.406 ) . In particular , there was a trend towards a reduced energy intake in the low-GI arm compared with the high-GI arm among boys . In addition , data from the 3 d food diaries showed that there was a tendency towards a reduced energy intake during the low-GI compared with the high-GI study period . In conclusion , although the difference in energy intake following the low-GI and high-GI breakfasts was not statistically significant , the reduced energy intake following the low-GI breakfast is encouraging . Both dietary fibre and carbohydrate type may affect GI , thus their potential and relative modulating effect on appetite requires further investigation Background The relationships between dietary fiber , whole grains , carbohydrate , glycemic index ( GI ) , glycemic load ( GL ) , and prostate cancer risk are unclear . We conducted a systematic review and meta- analysis to investigate these associations . Methods Relevant studies were identified by a search of PubMed data base and EMBASE data base up to April 2015 . A r and om effects model was used to calculate the summary relative risks ( RRs ) and their corresponding 95 % confidence intervals ( CIs ) . Results Twenty-seven epidemiological studies ( 18 case – control studies and nine cohort studies ) were included in the final analysis .  The pooled RRs of prostate cancer were 0.94 ( 95 % CI 0.85–1.05 , P=0.285 ) , 1.13 ( 95 % CI 0.98–1.30 , P=0.095 ) , 0.96 ( 95 % CI 0.81–1.14 , P=0.672 ) , 1.06 ( 95 % CI 0.96–1.18 , P=0.254 ) , and 1.04 ( 95 % CI 0.91–1.18 , P=0.590 ) for dietary fiber , whole grains , carbohydrate , GI , and GL , respectively . There was no evidence of significant publication bias based on the Begg ’s test and Egger ’s test . Conclusion The findings of this meta- analysis indicate that , based on available information , dietary fiber , whole grains , carbohydrate , GI , and GL are not associated with the risk of prostate cancer
In summary , GI breakfasts do not affect cognitive domains in children and adolescents
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 .