Endothelial FunctionPhase 4NCT01055418
Cognitive and Cerebral Blood Flow Effects of Vitamin C
A Phase 4 study testing Vitamin C in people with Endothelial Function and Cognition, run by Northumbria University at 1 site in United Kingdom.
Trial summary
This investigation is interested in the effects of high dose vitamin C on endothelial function in healthy humans. A high fat meal will be utilized to induce endothelial dysfunction. Read more about this study
- Who is it for?
- Ages 18 to 35 yearsHealthy volunteers can take part
- Conditions the study is for
- Endothelial Function, Cognition
- What is being tested?
- Vitamin C
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 24 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- Jan 2010to Sep 2010
- Phase
- Phase 4
- 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 35 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Male/Female,
- 18-35
Who cannot join
- Smokers,
- not proficient in English,
- are (or are seeking to become) pregnant, are currently taking illicit,
- over the counter/prescription medication (including the contraceptive pill),
- and/or dietary/herbal supplements.
- Food allergies or sensitivities that are relevant to the study,
Show all 10Show fewer
- a history of/current head trauma,
- learning difficulties,
- ADHD and
- migraines.
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
Brain, Performance and Nutrition Research Centre, Northumbria University
Newcastle upon Tyne, Tyne and Wear, NE1 8ST
About this study
This investigation is interested in the effects of high dose vitamin C on endothelial function in healthy humans. A high fat meal will be utilized to induce endothelial dysfunction. It is hypothesized that, via antioxidant actions, vitamin C will reverse these effects and in turn improve blood flow- the involvement of nitric oxide suggests that this could extend to cerebral blood flow. This will be monitored by trans cranial doppler flow meter and near infrared spectroscopy.
Read the detailed description
The acute effect of administering vitamins has received little research attention. The exceptions are a number of studies that have observed that single doses of a variety of vitamins, including Vitamin C, E and several B vitamins, ameliorate endothelial dysfunction in the periphery in participants who smoke, or suffer disorders such as diabetes mellitus and cardio-vascular disease. Endothelial function also varies in healthy people as a consequence of diet, and it is possible that antioxidant vitamins can attenuate the vaso-constriction associated with commonly consumed foodstuffs. Indeed, a study by Title et al (2000) showed that vitamin C improved endothelial function in the forearm following a glucose drink. Given the putative underlying mechanisms involved (e.g. nitric oxide synthesis) any improvement may well also extend to cerebral blood flow (CBF), and therefore improvements in aspects of cognitive function.
The study will therefore assess the effects of a single dose of 1000 mg of vitamin C on cognitive performance and cerebral arterial blood flow velocity (cBFV) using Trans-cranial Doppler, following a high fat meal that has been used in previous endothelial function research.
The high fat meal will be administered 2 hours before testing begins. Research shows that a meal of this type produces effects on the endothelium which are similar to those induced by dysfunctions such as diabetes i.e. blood flow restriction. No adverse effects have been reported with regards this methodology however.
In order to monitor the effects of vitamin C (or not in the case of placebo) on endothelial function and cerebral blood flow near infrared spectroscopy (NIRS) and trans cranial Doppler (TCD) recordings will be taken throughout (in the case of the former technique) and at intermittent stages (in the case of the latter). Both neuroimaging modalities, when used correctly) are entirely safe. Blood pressure readings will also be taken intermittently throughout testing sessions.
- Conditions
- Endothelial Function, Cognition
- Being tested
- Vitamin C
- Keywords
- Vitamin C, Cognitive performance, Cerebral blood flow, Trans cranial doppler, Near infrared spectroscopy
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Vitamin CDietary supplement
Vitamin C will be administered at a dose of 1000mg. There will be at least a 48 hour wash out period between both conditions (placebo and vitamin C), with the order dicteted by Latin square.
| Study group | Role | What they receive |
|---|---|---|
| placebo | Placebo comparator | Not described Receives: Dietary Supplement: Vitamin C |
| Vitamin C | Experimental | Not described Receives: Dietary Supplement: Vitamin C |
What is being measured
The primary outcome is the main question the study is designed to answer.
Endothelial function (using cerebral blood flow as a proxy measurement as measured by TCD and NIRS.
Measured: ~100 mins
Secondary outcomes (1)
Cognitive performance
Measured: ~50 mins
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Jan 2010 (estimated)
- Study startJan 2010
- Primary completionSep 2010
- Study completionSep 2010
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Endothelial FunctionStudies 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 4
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Investigator, Outcomes assessor
- Enrolment
- 24 participants (actual)
Sponsor and investigators
- Lead sponsor
- Northumbria University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, David Kennedy, Northumbria University
- Investigators
- David Kennedy, Study director, Northumbria University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01055418
- Sponsor's protocol ID
- 24AD1
- Status last verified
- May 2013
- First submitted
- 22 Jan 2010
- Last updated
- 3 May 2013
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 May 2013. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Cognitive and Cerebral Blood Flow Effects of Vitamin C
- ClinicalTrials.gov ID
- NCT01055418
- Acronym / sponsor ID
- 24AD1
- Conditions
- Endothelial Function, Cognition
- Keywords
- Vitamin C, Cognitive performance, Cerebral blood flow, Trans cranial doppler, Near infrared spectroscopy
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 24 participants (actual)
- Lead sponsor
- Northumbria UniversityUniversity, hospital or other
- Study start
- Jan 2010
- Primary completion
- Sep 2010 (actual)
- Study completion
- Sep 2010 (actual)
- First posted
- 25 Jan 2010 (estimated)
- 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.
This investigation is interested in the effects of high dose vitamin C on endothelial function in healthy humans. A high fat meal will be utilized to induce endothelial dysfunction. It is hypothesized that, via antioxidant actions, vitamin C will reverse these effects and in turn improve blood flow- the involvement of nitric oxide suggests that this could extend to cerebral blood flow. This will be monitored by trans cranial doppler flow meter and near infrared spectroscopy.
Detailed description
The acute effect of administering vitamins has received little research attention. The exceptions are a number of studies that have observed that single doses of a variety of vitamins, including Vitamin C, E and several B vitamins, ameliorate endothelial dysfunction in the periphery in participants who smoke, or suffer disorders such as diabetes mellitus and cardio-vascular disease. Endothelial function also varies in healthy people as a consequence of diet, and it is possible that antioxidant vitamins can attenuate the vaso-constriction associated with commonly consumed foodstuffs. Indeed, a study by Title et al (2000) showed that vitamin C improved endothelial function in the forearm following a glucose drink. Given the putative underlying mechanisms involved (e.g. nitric oxide synthesis) any improvement may well also extend to cerebral blood flow (CBF), and therefore improvements in aspects of cognitive function.
The study will therefore assess the effects of a single dose of 1000 mg of vitamin C on cognitive performance and cerebral arterial blood flow velocity (cBFV) using Trans-cranial Doppler, following a high fat meal that has been used in previous endothelial function research.
The high fat meal will be administered 2 hours before testing begins. Research shows that a meal of this type produces effects on the endothelium which are similar to those induced by dysfunctions such as diabetes i.e. blood flow restriction. No adverse effects have been reported with regards this methodology however.
In order to monitor the effects of vitamin C (or not in the case of placebo) on endothelial function and cerebral blood flow near infrared spectroscopy (NIRS) and trans cranial Doppler (TCD) recordings will be taken throughout (in the case of the former technique) and at intermittent stages (in the case of the latter). Both neuroimaging modalities, when used correctly) are entirely safe. Blood pressure readings will also be taken intermittently throughout testing sessions.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| placebo | Placebo comparator | Dietary Supplement: Vitamin C |
| Vitamin C | Experimental | Dietary Supplement: Vitamin C |
Who may qualify
- Ages
- 18 to 35 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- Male/Female,
- 18-35
Key exclusion criteria (10 listed)
- Smokers,
- not proficient in English,
- are (or are seeking to become) pregnant, are currently taking illicit,
- over the counter/prescription medication (including the contraceptive pill),
- and/or dietary/herbal supplements.
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 |
|---|---|---|
| Vitamin CVitamin C will be administered at a dose of 1000mg. There will be at least a 48 hour wash out period between both conditions (placebo and vitamin C), with the order dicteted by Latin square. | Dietary supplement | Vitamin C, placebo |
Primary outcome
Endothelial function (using cerebral blood flow as a proxy measurement as measured by TCD and NIRS.
Time frame: ~100 mins
1 secondary outcome
Cognitive performance
Time frame: ~50 mins
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 3 May 2013.
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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.
David Kennedy study director
Northumbria University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Vitamin C in people with Endothelial Function and Cognition, run by Northumbria University 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 2 inclusion and 10 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 3 May 2013. 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.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
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?
Endothelial function (using cerebral blood flow as a proxy measurement as measured by TCD and NIRS. (time frame: ~100 mins). 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 3 May 2013; AzTrials last refreshed its copy on 7 Nov 2026.