title: Sex differences in adolescents' glycaemic and insulinaemic responses to high and low glycaemic index breakfasts: a randomised control trial.
abstract: During puberty young people undergo significant hormonal changes which affect metabolism and, subsequently, health. Evidence suggests there is a period of transient pubertal insulin resistance, with this effect greater in girls than boys. However, the response to everyday high and low glycaemic index (GI) meals remains unknown. Following ethical approval, forty adolescents consumed a high GI or low GI breakfast, in a randomised cross-over design. Capillary blood samples were taken during a 2-h postprandial period, examining the glycaemic and insulinaemic responses. Maturity offset and homoeostatic model assessment (HOMA) were also calculated. The glycaemic response to the breakfasts was similar between boys and girls, as shown by similar peak blood glucose concentrations and incremental AUC (IAUC) following both high and low GI breakfasts (all P>0·05). Girls exhibited a higher peak plasma insulin concentration 30 min post-breakfast following both high GI (P=0·043, g=0·69) and low GI (P=0·010, g=0·84) breakfasts, as well as a greater IAUC following high GI (P=0·041, g=0·66) and low GI (P=0·041, g=0·66) breakfasts. HOMA was positively correlated with the insulinaemic responses (all P<0·0005) and maturity offset (P=0·037). The findings of the present study suggest that pubertal insulin resistance affects the postprandial insulinaemic responses to both high and low GI meals. Specifically, girls exhibit a greater insulinaemic response than boys to both meals, despite similar glycaemic responses. This study is the first to report the glycaemic and insulinaemic responses to everyday meals in boys and girls, supporting the recommendation for young people to base their diet on low GI carbohydrates.
authors.affiliation: Exercise and Health Research Group, Department of Sports Science, Sport Health and Performance Enhancement (SHAPE) Research Centre,Nottingham Trent University,Nottingham NG11 8NS,UK.
authors.forename: Simon B
authors.initials: SB
authors.lastname: Cooper
authors.affiliation: Exercise and Health Research Group, Department of Sports Science, Sport Health and Performance Enhancement (SHAPE) Research Centre,Nottingham Trent University,Nottingham NG11 8NS,UK.
authors.forename: Karah J
authors.initials: KJ
authors.lastname: Dring
authors.affiliation: Exercise and Health Research Group, Department of Sports Science, Sport Health and Performance Enhancement (SHAPE) Research Centre,Nottingham Trent University,Nottingham NG11 8NS,UK.
authors.forename: John G
authors.initials: JG
authors.lastname: Morris
authors.affiliation: Exercise and Health Research Group, Department of Sports Science, Sport Health and Performance Enhancement (SHAPE) Research Centre,Nottingham Trent University,Nottingham NG11 8NS,UK.
authors.forename: Ben E W
authors.initials: BE
authors.lastname: Cousins
authors.affiliation: Exercise and Health Research Group, Department of Sports Science, Sport Health and Performance Enhancement (SHAPE) Research Centre,Nottingham Trent University,Nottingham NG11 8NS,UK.
authors.forename: Maria L
authors.initials: ML
authors.lastname: Nute
authors.affiliation: Exercise and Health Research Group, Department of Sports Science, Sport Health and Performance Enhancement (SHAPE) Research Centre,Nottingham Trent University,Nottingham NG11 8NS,UK.
authors.forename: Mary E
authors.initials: ME
authors.lastname: Nevill
mesh_terms: D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism; D062408:Breakfast; D002648:Child; D004032:Diet; D004040:Dietary Carbohydrates / Q000097:blood; D005247:Feeding Behavior; D005260:Female; D038321:Glycemic Index; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008297:Male; D019518:Postprandial Period; D011627:Puberty; D012737:Sex Factors
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D007328:Insulin
keywords:  GI glycaemic index;  HOMA homoeostatic model assessment;  IAUC incremental AUC; Breakfast glycaemic index; Insulin resistance; Puberty; Sex differences