title: Postprandial effect of breakfast glycaemic index on vascular function, glycaemic control and cognitive performance (BGI study): study protocol for a randomised crossover trial.
abstract: Postprandial glycaemic response affects cognitive and vascular function. The acute effect of breakfast glycaemic index on vascular parameters is not sufficiently known. Also, the influence of breakfasts with different glycaemic index on cognitive performance has been mostly studied in children and adolescents with varying results. Therefore, the purpose of this study is to analyse the postprandial effect of high and low glycaemic index breakfasts on vascular function and cognitive performance and their relationship with postprandial glycaemic response in healthy young adults.
  
  
  
  This is a crossover clinical trial targeting adults (aged 20-40 years, free from cardiovascular disease) selected by consecutive sampling at urban primary care health clinics in Salamanca (Spain). Each subject will complete three interventions with a washout period of one week: a control condition (consisting of water); a low glycaemic index breakfast (consisting of dark chocolate, walnuts, yogurt and an apple, with an overall glycaemic index of 29.4 and an energy contribution of 1489 kJ); and a high glycaemic index breakfast (consisting of bread, grape juice and strawberry jam, with an overall glycaemic index of 64.0 and an energy contribution of 1318 kJ). The postprandial effect will be assessed at 60 and 120 minutes from each breakfast including blood sampling and cognitive performance evaluations. Measurements of arterial stiffness and central haemodynamic parameters will be taken at -10, 0, 15, 30, 45, 60, 75, 90, 105 and 120 minutes.
  
  
  
  The differences in postprandial glycaemic response due to breakfast glycaemic index could affect vascular parameters and cognitive performance with important applications and implications for the general population. This could provide necessary information for the establishment of new strategies in terms of nutritional education and work performance improvement.
  
  
  
  ClinicalTrials.gov: ﻿ NCT02616276 ﻿. Registered on 19 November 2015.
authors: Primary Care Research Unit, The Alamedilla Health Centre, Castilla and León Health Service (SACYL), Institute of Biomedical Research of Salamanca (IBSAL), Salamanca, Spain. natalia.san.ag@gmail.com.|Primary Care Research Unit, The Alamedilla Health Centre, Av. Comuneros N° 27, 37003, Salamanca, Spain. natalia.san.ag@gmail.com.
authors: Natalia
authors: N
authors: Sanchez-Aguadero
authors: Primary Care Research Unit, The Alamedilla Health Centre, Castilla and León Health Service (SACYL), Institute of Biomedical Research of Salamanca (IBSAL), Salamanca, Spain.|Department of Biomedical and Diagnostic Sciences, University of Salamanca, Salamanca, Spain.
authors: Luis
authors: L
authors: Garcia-Ortiz
authors: Department of Statistics, University of Salamanca, Salamanca, Spain.|Primary Care Research Unit, The Alamedilla Health Centre, Institute of Biomedical Research of Salamanca (IBSAL), Salamanca, Spain.
authors: Maria C
authors: MC
authors: Patino-Alonso
authors: Primary Care Research Unit, The Alamedilla Health Centre, Institute of Biomedical Research of Salamanca (IBSAL), Salamanca, Spain.|School of Labor Relations, University of Salamanca Affiliated Centre, Zamora, Spain.
authors: Sara
authors: S
authors: Mora-Simon
authors: Primary Care Research Unit, The Alamedilla Health Centre, Castilla and León Health Service (SACYL), Institute of Biomedical Research of Salamanca (IBSAL), Salamanca, Spain.|Department of Medicine, University of Salamanca, Salamanca, Spain.
authors: Manuel A
authors: MA
authors: Gomez-Marcos
authors: Primary Care Research Unit, The Alamedilla Health Centre, Castilla and León Health Service (SACYL), Institute of Biomedical Research of Salamanca (IBSAL), Salamanca, Spain.
authors: Rosario
authors: R
authors: Alonso-Dominguez
authors: Primary Care Research Unit, The Alamedilla Health Centre, Castilla and León Health Service (SACYL), Institute of Biomedical Research of Salamanca (IBSAL), Salamanca, Spain.
authors: Benigna
authors: B
authors: Sanchez-Salgado
authors: Primary Care Research Unit, The Alamedilla Health Centre, Castilla and León Health Service (SACYL), Institute of Biomedical Research of Salamanca (IBSAL), Salamanca, Spain.|Department of Nursing and Physiotherapy, University of Salamanca, Salamanca, Spain.
authors: Jose I
authors: JI
authors: Recio-Rodriguez
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D062408:Breakfast; D002985:Clinical Protocols; D003071:Cognition; D018592:Cross-Over Studies; D002149:Energy Intake; D005260:Female; D038321:Glycemic Index; D006439:Hemodynamics; D006801:Humans; D008297:Male; D019518:Postprandial Period; D012107:Research Design; D013030:Spain; D013997:Time Factors; D059289:Vascular Stiffness; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001786:Blood Glucose
keywords: Blood glucose; Cognition; Glycaemic index; Postprandial period; Vascular stiffness