Effects of Acute Intake of Flavanols on Cerebral Oxygenation and Cognition in Young Male Adults

Study Overview
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Brief Summary
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The study evaluates the impact of one acute dose of cocoa flavanols on brain oxygenation during a hypercapnia challenge, as well as impact on cognitive performance in young healthy males. It further assesses the impact of flavanols on peripheral vascular function, as measured by brachial Flow-mediated dilation (FMD). All participants received a high-flavanol cocoa intervention (185.5 mg of flavanols (-)-epicatechin and (+)- catechin) and a low-flavanol cocoa intervention (< 4 mg of flavanols). It is hypothesized that the high-flavanol intervention increases cerebral oxygenation during hypercapnia and vascular function in comparison to the low-flavanol intervention.

Detailed Description
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Cocoa flavanols have been shown to be protective against vascular disease in humans, as evidenced by improvements in peripheral endothelial function (as measured by brachial Flow-mediated dilatation, FMD). There is also emerging evidence suggesting that flavanol-rich diets protect against cognitive aging, but mechanisms remain elusive. In this study the investigators suggest that such mechanisms might be associated with benefits within the brain vasculature. The aim of the present study was therefore to determine whether intake of flavanols enhances cerebral oxygenation in frontal cortical areas of the brain during a hypercapnia challenge (which is a well-established biomarker of vascular reactivity in the brain) to a greater extent than a low-flavanol intervention in young healthy adults.

Official Title
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A Placebo-controlled, Randomized, Double-masked, Cross-over Acute Intervention Study Investigating the Effects of Flavanols on Cerebral Oxygenation and Cognition in Young Adults

Conditions
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Healthy

Intervention / Treatment
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* Dietary Supplement: High-flavanol cocoa powder
* Dietary Supplement: Low-flavanol cocoa powder


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male 18-45 years old Exclusion Criteria: smokers hypertensive with history of cerebrovascular, cardiovascular or respiratory disease allergies or intolerances to ingredients present in cocoa powders taking long-term medication (e.g., hyperlipidaemia) on antibiotics for the previous 3 months before enrollment suffering from blood-clotting disorders known infections at the time of the study on a weight-reducing regimen

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: High-flavanol Cocoa powder<br>Dietary supplement: single serving of a high-flavanol cocoa powder containing 150 mg of (-)-epicatechin and 35.5 mg of (+)-catechin | Dietary Supplement: High-flavanol cocoa powder<br>* Non-alkalized fat-reduced cocoa powder (Natural Acticoa)<br>|
| Active Comparator: Low-flavanol Cocoa powder<br>Dietary supplement: single serving of a low-flavanol cocoa powder intervention containing < 4 mg of (-)-epicatechin and (+)-catechin and matched as best as possible for macronutrients and micronutrients, such as caffeine and theobromine. | Dietary Supplement: Low-flavanol cocoa powder<br>* Alkalized fat-reduced cocoa powder (10/12 DDP Royal Dutch)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cortical Blood Oxygenation reactivity to hypercapnia using functional near-infrared spectroscopy (fNIRS) | Cerebral oxygenated haemoglobin maximum levels in the frontal cortical regions of the brain during the 5% carbon-dioxide breathing challenge (average across minutes 3 and 4 of breathing challenge) | Change from baseline to 2 hours | 
| Time to reach 90% of maximum cortical blood oxygenation during hypercapnia using functional near-infrared spectroscopy (fNIRS) | Time to reach 90% of maximum oxygenated haemoglobin in the frontal cortical regions of the brain during the 5% carbon-dioxide breathing challenge | Change from baseline to 2 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cortical Blood Deoxygenation reactivity to hypercapnia using functional near-infrared spectroscopy (fNIRS) | Cerebral deoxygenated haemoglobin minimal levels in the frontal cortical regions of the brain during the 5% carbon-dioxide breathing challenge (average across minutes 3 and 4 of breathing challenge) | Change from baseline to 2 hours | 
| Inverse Efficiency scores in a Modified version of the Stroop Task | The modified Stroop included task blocks (designated as Colour match; Word match; Stroop and Double Stroop) of increasing difficulty so that performance could be compared between simple and more demanding tasks. Reaction time and accuracy of choice were recorded to estimate inverse efficiency scores (in seconds). Higher 'inverse efficiency scores' reflect worse performance on the task, whilst lower scores reflects better performance. | 2 hours post intervention | 
| Flow-mediated dilatation (FMD) of the brachial artery using ultrasound (expressed as % FMD: change in brachial diameter from baseline to peak dilation following 5 minutes of arterial occlusion).. | FMD of the brachial artery | Change from baseline to 2 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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flavanol, cocoa, brain, oxygenation, vascular, cognition, hypercapnia, functional near-infrared spectroscopy