Eating grapes before mental stress to protect brain and blood vessel health in young adults
Official title: A Placebo-controlled, Randomized, Double-masked, Cross-over Acute Intervention Study Investigating the Effects of Grape Polyphenols on Cerebral Oxygenation, Cognitive and Vascular Function in the Context of Mental Stress in Young Adults
Run by University of Birmingham · NCT06923722 · Data updated 2026-11-12
This test sees if eating a high-flavonoid grape snack before mental stress helps protect brain oxygenation, blood vessel function, mood, and thinking in healthy 18–40-year-olds.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 18 Years to 40 Years |
| Sex | All |
| Enrollment | 44 (estimated) |
| Sponsor | University of Birmingham Academic / other |
| Locations | 1 site (Birmingham, West Midlands) |
| Status | Recruiting |
| Started | April 1, 2025 |
| Main results expected | March 31, 2026 |
| Study ends | March 31, 2026 |
| Registry record updated | December 4, 2025 |
| Trial ID | NCT06923722 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Healthy non-smoking men and women aged 18–40 who are not on long-term medications or dietary supplements and have no major chronic illnesses are the intended participants.
✕Probably not a fit
People who smoke, drink heavily, have cardiovascular, metabolic, respiratory, liver, inflammatory or clotting disorders, who take long-term medications or recent antibiotics, or who are allergic to grapes are unlikely to be eligible or to benefit.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
In this crossover intervention, healthy adults aged 18–40 receive both a high-flavonoid grape supplement (60 g freeze-dried grape powder, equivalent to about 300 g fresh grapes) and an isocaloric low-flavonoid control on separate visits before undergoing a standardized mental stress task. Researchers will measure cortical oxygenation, cognitive performance, mood, and peripheral vascular function (brachial flow-mediated dilatation), and will explore influences of habitual diet, gut microbiome composition and cardiorespiratory fitness. Secondary measures include VO2 max testing and faecal samples to assess microbiome metabolites such as short-chain fatty acids. The design tests whether an acute grape "stress snack" can prevent stress-induced declines in vascular and brain function.
Why it matters
Potential benefit: If effective, grapes could be a simple, widely available 'stress snack' to help preserve brain oxygenation, cognitive performance, and vascular health during periods of acute mental stress.
How similar studies have gone: Previous work shows flavonoid-rich foods can improve peripheral and cerebrovascular function and blunt stress-related vascular declines, but using grapes specifically to protect brain oxygenation and cognition during acute mental stress is relatively novel.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Males and females * 18 - 40 years old Exclusion Criteria: * Smokers * Consumes \> 21 units of alcohol per week * History of cardiovascular, respiratory, metabolic, liver or inflammatory diseases * Suffers from blood-clotting disorders * Allergies or intolerances to foods * On a weight reducing dietary regiment * Currently taking dietary supplements, including fatty acids and vitamins * On long-term medication or have been on antibiotics in the last 3 months * Has an infection at present (e.g. cold) or viral infection
Where it's running
-
School of Sport, Exercise & Rehabilitation Sciences
Birmingham, West Midlands, United Kingdom Recruiting
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.