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Postprandial Effect of Breakfast Glycemic Index on Vascular Function, Insulinemia and Cognitive Performance (BGI Study)

Not Applicable
Completed
Conditions
Healthy
Interventions
Other: Control breakfast
Other: High glycemic index breakfast
Other: Low glycemic index breakfast
Registration Number
NCT02616276
Lead Sponsor
Fundacion para la Investigacion y Formacion en Ciencias de la Salud
Brief Summary

This is a crossover clinical trial aimed at adults (aged 20-40 years, with no 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: control breakfast (water), low glycemic index breakfast (apple, yogurt, walnuts and black chocolate) and high glycemic index breakfast (grape juice, bread and strawberry jam). The postprandial effect will be assessed at 60 and 120 minutes from each breakfast, measuring blood glucose and insulin and cognitive performance. Measurements will be performed of central blood pressure, augmentation index, pulse wave velocity, cardiac output and total peripheral vascular resistance at minutes (-10, 0, +15, +30, +45, +60, +75, +90, +105 and +120).

Detailed Description

Objectives:

The primary objective of this study is to evaluate the postprandial effect of low and high glycemic index breakfasts on vascular function, measured by central blood pressure, augmentation index and pulse wave velocity, in a sample of healthy young adults. The second objective is to assess the postprandial effect of low and high glycemic index breakfasts on blood glucose and insulin values in a sample of healthy young adults. The third and last objective is to assess the postprandial effect of low and high glycemic index breakfasts on cognitive performance in a sample of healthy young adults.

Design and setting:

A controlled crossover clinical trial, where each subject will complete three interventions (control breakfast, high glycemic index breakfast and low glycemic index breakfast), with a washout period of one week between each, and whose order will be determined by a randomization sequence generated using the Randomization.com software (http://www.randomization.com).

Study setting:

The study will be conducted in the primary care health area of Salamanca in the Research Unit of La Alamedilla, belonging to the Spanish Network for Preventive Activities and Health Promotion (redIAPP) and Salamanca Institute for Biomedical Research (IBSAL).

Study population:

The subjects of the study population will be selected by consecutive sampling in the primary care clinics of urban health centers in Salamanca (Spain) between 2015 and 2016. As this crossover clinical trial, a consecutive sampling will ensure comparability of the groups.

Intervention:

Each of the three scheduled visits will last approximately 2 and a half hours, and will be structured as follows:

Min -10: Measurement of clinical blood pressure, central blood pressure, and central hemodynamic parameters; evaluation of cognitive performance; laboratory test sampling to determine glucose and insulin blood levels.

Min 0: Measurement of central blood pressure and central hemodynamic parameters; intake of assigned breakfast (10 minutes).

Min +15, +30, +45: Measurement of central blood pressure and central hemodynamic parameters.

Min +60: Measurement of central blood pressure and central hemodynamic parameters; evaluation of cognitive performance; laboratory test sampling to determine glucose and insulin blood levels.

Min +75, +90, +105: Measurement of central blood pressure and central hemodynamic parameters.

Min +120: Measurement of central blood pressure and central hemodynamic parameters; evaluation of cognitive performance; laboratory test sampling to determine glucose and insulin blood levels.

Recruitment & Eligibility

Status
COMPLETED
Sex
All
Target Recruitment
40
Inclusion Criteria
  • Young adults.
  • Aged between 20 and 40 years.
  • Both sexes.
  • Those agree to sign the informed consent.
Exclusion Criteria
  • History of cardiovascular events (acute myocardial infarction, stroke, etc.).
  • History of hypertension, diabetes mellitus or dyslipidemia.
  • Pharmacological treatment for any of the above conditions.
  • Diagnosis of clinically demonstrable neurological and/or neuropsychological disease.
  • Excessive consumption of toxic substances.
  • Celiac patients and/or those intolerant to lactose.
  • Subjects on a low-calorie and/or low-sodium diet.
  • Pregnant women.
  • Those with any other circumstance that the investigators consider could interfere with the study procedures.

Study & Design

Study Type
INTERVENTIONAL
Study Design
CROSSOVER
Arm && Interventions
GroupInterventionDescription
ControlControl breakfastControl breakfast
ControlLow glycemic index breakfastControl breakfast
Intervention 2Control breakfastLow glycemic index breakfast
Intervention 2Low glycemic index breakfastLow glycemic index breakfast
ControlHigh glycemic index breakfastControl breakfast
Intervention 1Control breakfastHigh glycemic index breakfast
Intervention 1Low glycemic index breakfastHigh glycemic index breakfast
Intervention 1High glycemic index breakfastHigh glycemic index breakfast
Intervention 2High glycemic index breakfastLow glycemic index breakfast
Primary Outcome Measures
NameTimeMethod
Augmentation indexChanges in augmentation index at 1 week, according to glycemic index of the breakfast

Measurement by Mobil-O-Graph® device

Secondary Outcome Measures
NameTimeMethod
Central blood pressureChanges in central blood pressure at 1 week, according to glycemic index of the breakfast

Measurement by Mobil-O-Graph® device

Delayed verbal memoryChanges in delayed verbal memory at 1 week, according to glycemic index of the breakfast

Assessment by free recall of the words learnt in the first part of the study after a period of approximately 10 minutes

Pulse wave velocityChanges in pulse wave velocity at 1 week, according to glycemic index of the breakfast

Measurement by Mobil-O-Graph® device

Blood glucoseChanges in blood glucose at 1 week, according to glycemic index of the breakfast

Measurement by laboratory test sampling

Insulin valuesChanges in insulin values at 1 week, according to glycemic index of the breakfast

Measurement by laboratory test sampling

Immediate verbal memoryChanges in immediate verbal memory at 1 week, according to glycemic index of the breakfast

Assessment by immediate recall of a list of 15 words, in three attempts

Phonological fluencyChanges in phonological fluency at 1 week, according to glycemic index of the breakfast

Assessment by enumerating for one minute as many words as possible starting with different letters

AttentionChanges in attention at 1 week, according to glycemic index of the breakfast

Assessment by Trail Making Test A

Sustained attentionChanges in sustained attention at 1 week, according to glycemic index of the breakfast

Assessment by Stroop test

Selective attentionChanges in selective attention at 1 week, according to glycemic index of the breakfast

Assessment by Stroop test

Processing speedChanges in processing speed at 1 week, according to glycemic index of the breakfast

Assessment by Trail Making Test B

Executive functionsChanges in executive functions at 1 week, according to glycemic index of the breakfast

Assessment by Trail Making Test B

Working memoryChanges in working memory at 1 week, according to glycemic index of the breakfast

Assessment by WAIS Digit Span Backward test

Trial Locations

Locations (1)

Primary Care Research Unit - The Alamedilla Center for Health

🇪🇸

Salamanca, Spain

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