HealthyNCT07864545
Impact of Dietary Flavanols on Microvascular Function in Young Females During Mental Stress
A study testing High-flavanol cocoa powder and Low-flavanol cocoa powder in people with Healthy, run by University of Birmingham at 1 site in United Kingdom.
Trial summary
The aim of this project is to examine whether flavonoids, which are small molecules naturally present in cocoa, as well as fruits and vegetables such as berries, tea, citrus fruits, apple (typically responsible for giving these foods their strong colours), can be used to protect the human vascular system. Read more about this study
- Who is it for?
- Ages 18 to 26 years, women onlyHealthy volunteers can take part
- Conditions the study is for
- Healthy
- What is being tested?
- High-flavanol cocoa powder and Low-flavanol cocoa powder
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 23 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 7 Feb 2020to 23 Feb 2023
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 26 years
- Women only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Female (White or Black African or South Asian ethnicity (with ethnic roots in India, Pakistan, Bangladesh, Sri Lanka, or Nepal)
- Healthy
- Aged 18 to 26 years old
- Do not smoke
- Do not consume more than 21 units of alcohol per week
- Have no history of cardiovascular, respiratory, metabolic, liver, inflammatory diseases
Show all 13Show fewer
- Do not suffer from blood-clotting disorders
- Do not have allergies or intolerances to any foods
- Are not on a weight reducing dietary regime
- Are not taking any dietary supplements, including fatty acids and vitamins
- Are not taking any long-term medication or been on antibiotics for the last 3 months
- You do not have an infection at the time of the intervention (e.g. cold)
- Experience a regular menstrual cycle (controlled by contraceptive pill or otherwise)
Who cannot join
- Male
- Not from White European or South Asian Ethnicity
- Aged 27 years or older
- Smoke
- Consume more than 21 units of alcohol per week
- Have history of cardiovascular, respiratory, metabolic, liver, inflammatory diseases
Show all 13Show fewer
- Suffer from blood-clotting disorders
- Have allergies or intolerances to any foods
- Are on a weight reducing dietary regime
- Are taking any dietary supplements, including fatty acids and vitamins
- Are taking any long-term medication or been on antibiotics for the last 3 months
- Have an infection at the time of the intervention (e.g. cold)
- Experience a irrregular menstrual cycle
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
School of Sport, Exercise & Rehabilitation Sciences
Birmingham, West Midlands, B15 2TT
About this study
Official title: Acute Effects of Dietary Flavanols on Microvascular Responses to Mental Stress in White European and South Asian Women: A Randomised, Placebo-controlled, Double-blind, Cross-over Preliminary Intervention Study
The aim of this project is to examine whether flavonoids, which are small molecules naturally present in cocoa, as well as fruits and vegetables such as berries, tea, citrus fruits, apple (typically responsible for giving these foods their strong colours), can be used to protect the human vascular system. Impaired vascular function, as determined by measuring vasodilator responses to various everyday stimuli, can be linked to elevated blood pressure (hypertension) and prevalence of cardiovascular disease. Vascular response to mental stress in particular have been shown to be associated with future risk of cardiovascular disease. Findings from this study could have implications for effective prevention of cardiovascular events in groups with increased cardiovascular risk, such as South Asians and in particular, South Asian women.
Read the detailed description
Psychological stress is linked to cardiovascular health, specifically there is evidence of increased risk of cardiovascular events following episodes of psychological stress, suggesting a vulnerability of the cardiovascular system to the experience of stress.
Individuals of South Asian ethnicity are at higher risk of CVD but also have higher incidence of stress and mood disorders. SA women, in particular, have higher incidence of mental disorders and depression, compared to age-matched WE women, suggesting that this may be a particular vulnerable group.
Flavanols are polyphenolic molecules abundant in cocoa, apples, berries and tea, which have been shown to exert both acute and chronic benefits in the vascular system, by improving conduit artery endothelial function and blood pressure.
However, the effect of flavonoid-rich interventions in ethnic groups at higher risk of CVD, such as South Asians, have not been studied. Intake of flavonoid-rich foods in this population may be able to protect vascular function, particularly in the context of psychological stress.
In this preliminary acute study (randomised, placebo-controlled, double-blind, cross-over intervention) in SA and WE women we assess the effect of an acute cocoa flavanol intervention on the microvascular and cardiovascular responses to acute mental stress. We further compare the impact of flavanols on microvascular responses between women who showed vasodilation in comparison to women that exhibit vasoconstriction during mental stress.
- Conditions
- Healthy
- Being tested
- High-flavanol cocoa powder, Low-flavanol cocoa powder
- Keywords
- microvascular function, flavanols, polyphenols, cocoa, mental stress, female, south asian, white european, near-infrared spectroscopy, vasoconstriction, vasodilator
- Medical subject headings
- Stress, Psychological
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
High-flavanol cocoa powderDietary supplement
12 g of fat-reduced natural cocoa powder containing 695 mg of total flavanols, including 150 mg (-)-epicatechin
Low-flavanol cocoa powderDietary supplement
12 g of fat-reduced alkalized cocoa powder containing 5.6 mg of total flavanols
| Study group | Role | What they receive |
|---|---|---|
| High-flavanol cocoa powder | Experimental | 12 g of fat-reduced natural cocoa powder containing 695 mg of total flavanols, including 150 mg (-)-epicatechin Receives: Dietary Supplement: High-flavanol cocoa powder |
| Low-flavanol cocoa powder | Placebo comparator | 12 g of fat-reduced alkalized cocoa powder containing 5.6 mg of total flavanols Receives: Dietary Supplement: Low-flavanol cocoa powder |
What is being measured
The primary outcome is the main question the study is designed to answer.
Forearm oxygen saturation (NIRS) during mental stress (SO2)
Forearm levels of tissue saturation (SO2) will be assessed by functional Near-Infrared Spectroscopy (fNIRS). The NIRS device measures changes in chromophore concentrations of oxyhaemoglobin (O2Hb) and deoxyhaemoglobin (HHb), providing depth-resolved measures of total tissue oxygen saturation: oxyHb /(oxyHb+deoxyHb)
Measured: Change from pre-intervention baseline to 1. 5 hours post-intervention (during mental stress)
Secondary outcomes (6)
Forearm total haemoglobin (NIRS) during mental stress (total Hb)
Forearm levels of tissue saturation (totalHb) will be assessed by functional Near-Infrared Spectroscopy (fNIRS). The NIRS device measures changes in chromophore concentrations of oxyhaemoglobin (O2Hb) and deoxyhaemoglobin (HHb), providing depth-resolved measures of changes in total haemoglobin, which is an index of tissue perfusion/blood flow: oxyHb+deoxyHb
Measured: Change from pre-intervention to 1.5 hours post-intervention (during mental stress)
Beat-to-beat systolic blood pressure (SBP)
Beat-to-beat systolic blood pressure (SBP) will be measured using a Finometer (mmHg)
Measured: Change from pre-intervention baseline to 1.5 hour post-intervention (during mental stress)
Beat-to-beat diastolic blood pressure (DBP)
Beat-to-beat diastolic blood pressure (DBP) will be measured using a Finometer (mmHg)
Measured: Change from pre-intervention to 1. 5 hours post-intervention (during mental stress)
Beat-to-beat mean arterial pressure (MAP)
Beat-to-beat mean arterial pressure (MAP) will be estimated from beat to beat diastolic and systolic blood pressure
Measured: Change from pre-intervention to 1. 5 hours post-intervention (during mental stress
Forearm Vascular Conductance index (FVC) during mental stress
Forearm levels of vascular conductance (FVC) will be assessed by functional Near-Infrared Spectroscopy (fNIRS). The NIRS device measures changes in chromophore concentrations of oxyhaemoglobin (O2Hb) and deoxyhaemoglobin (HHb), which is used to estimate totalHb. Pulsatile (beat to beat) Arterial Blood pressure will be monitored using a Finometer® MIDI (Finapres Medical Systems) during mental stress. FVC index will be estimated by dividing ∆totalHb by Mean Arterial Blood pressure
Measured: Change from pre-intervention to 1. 5 hours post-intervention (during mental stress)
Heart rate (HR) during mental stress
Heart rate (HR, bpm) is assessed using an electrocardiogram.
Measured: Change from pre-intervention to 1. 5 hours post-intervention (during mental stress)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Oct 2026
- Study start7 Feb 2020
- Primary completion23 Feb 2023
- Study completion23 Feb 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 23 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Birmingham
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07864545
- Sponsor's protocol ID
- ERN17_1755B
- Status last verified
- Aug 2026
- First submitted
- 2 Sep 2026
- Last updated
- 7 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 7 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Acute Effects of Dietary Flavanols on Microvascular Responses to Mental Stress in White European and South Asian Women: A Randomised, Placebo-controlled, Double-blind, Cross-over Preliminary Intervention Study
- ClinicalTrials.gov ID
- NCT07864545
- Acronym / sponsor ID
- ERN17_1755B
- Conditions
- Healthy
- Keywords
- microvascular function, flavanols, polyphenols, cocoa, mental stress, female, south asian, white european
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 23 participants (actual)
- Lead sponsor
- University of BirminghamUniversity, hospital or other
- Study start
- 7 Feb 2020 (actual)
- Primary completion
- 23 Feb 2023 (actual)
- Study completion
- 23 Feb 2023 (actual)
- First posted
- 7 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of this project is to examine whether flavonoids, which are small molecules naturally present in cocoa, as well as fruits and vegetables such as berries, tea, citrus fruits, apple (typically responsible for giving these foods their strong colours), can be used to protect the human vascular system. Impaired vascular function, as determined by measuring vasodilator responses to various everyday stimuli, can be linked to elevated blood pressure (hypertension) and prevalence of cardiovascular disease. Vascular response to mental stress in particular have been shown to be associated with future risk of cardiovascular disease. Findings from this study could have implications for effective prevention of cardiovascular events in groups with increased cardiovascular risk, such as South Asians and in particular, South Asian women.
Detailed description
Psychological stress is linked to cardiovascular health, specifically there is evidence of increased risk of cardiovascular events following episodes of psychological stress, suggesting a vulnerability of the cardiovascular system to the experience of stress.
Individuals of South Asian ethnicity are at higher risk of CVD but also have higher incidence of stress and mood disorders. SA women, in particular, have higher incidence of mental disorders and depression, compared to age-matched WE women, suggesting that this may be a particular vulnerable group.
Flavanols are polyphenolic molecules abundant in cocoa, apples, berries and tea, which have been shown to exert both acute and chronic benefits in the vascular system, by improving conduit artery endothelial function and blood pressure.
However, the effect of flavonoid-rich interventions in ethnic groups at higher risk of CVD, such as South Asians, have not been studied. Intake of flavonoid-rich foods in this population may be able to protect vascular function, particularly in the context of psychological stress.
In this preliminary acute study (randomised, placebo-controlled, double-blind, cross-over intervention) in SA and WE women we assess the effect of an acute cocoa flavanol intervention on the microvascular and cardiovascular responses to acute mental stress. We further compare the impact of flavanols on microvascular responses between women who showed vasodilation in comparison to women that exhibit vasoconstriction during mental stress.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| High-flavanol cocoa powder | Experimental | Dietary Supplement: High-flavanol cocoa powder12 g of fat-reduced natural cocoa powder containing 695 mg of total flavanols, including 150 mg (-)-epicatechin |
| Low-flavanol cocoa powder | Placebo comparator | Dietary Supplement: Low-flavanol cocoa powder12 g of fat-reduced alkalized cocoa powder containing 5.6 mg of total flavanols |
Who may qualify
- Ages
- 18 to 26 years
- Sex
- Female only
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (13 listed)
- Female (White or Black African or South Asian ethnicity (with ethnic roots in India, Pakistan, Bangladesh, Sri Lanka, or Nepal)
- Healthy
- Aged 18 to 26 years old
- Do not smoke
- Do not consume more than 21 units of alcohol per week
Key exclusion criteria (13 listed)
- Male
- Not from White European or South Asian Ethnicity
- Aged 27 years or older
- Smoke
- Consume more than 21 units of alcohol per week
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| High-flavanol cocoa powder12 g of fat-reduced natural cocoa powder containing 695 mg of total flavanols, including 150 mg (-)-epicatechin | Dietary supplement | High-flavanol cocoa powder |
| Low-flavanol cocoa powder12 g of fat-reduced alkalized cocoa powder containing 5.6 mg of total flavanols | Dietary supplement | Low-flavanol cocoa powder |
Primary outcome
Forearm oxygen saturation (NIRS) during mental stress (SO2)
Time frame: Change from pre-intervention baseline to 1. 5 hours post-intervention (during mental stress)
Forearm levels of tissue saturation (SO2) will be assessed by functional Near-Infrared Spectroscopy (fNIRS). The NIRS device measures changes in chromophore concentrations of oxyhaemoglobin (O2Hb) and deoxyhaemoglobin (HHb), providing depth-resolved measures of total tissue oxygen saturation: oxyHb /(oxyHb+deoxyHb)
6 secondary outcomes
Forearm total haemoglobin (NIRS) during mental stress (total Hb)
Time frame: Change from pre-intervention to 1.5 hours post-intervention (during mental stress)
Beat-to-beat systolic blood pressure (SBP)
Time frame: Change from pre-intervention baseline to 1.5 hour post-intervention (during mental stress)
Beat-to-beat diastolic blood pressure (DBP)
Time frame: Change from pre-intervention to 1. 5 hours post-intervention (during mental stress)
Beat-to-beat mean arterial pressure (MAP)
Time frame: Change from pre-intervention to 1. 5 hours post-intervention (during mental stress
Forearm Vascular Conductance index (FVC) during mental stress
Time frame: Change from pre-intervention to 1. 5 hours post-intervention (during mental stress)
Heart rate (HR) during mental stress
Time frame: Change from pre-intervention to 1. 5 hours post-intervention (during mental stress)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Oct 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing High-flavanol cocoa powder and Low-flavanol cocoa powder in people with Healthy, run by University of Birmingham at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 13 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 7 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Forearm oxygen saturation (NIRS) during mental stress (SO2) (time frame: Change from pre-intervention baseline to 1. 5 hours post-intervention (during mental stress)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 Oct 2026.