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Cognitive and Cerebral Blood Flow Effects of Vitamin C

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01055418
Recruitment Status : Completed
First Posted : January 25, 2010
Last Update Posted : May 3, 2013
Information provided by (Responsible Party):
David Kennedy, Northumbria University

Brief 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. 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.

Condition or disease Intervention/treatment Phase
Endothelial Function Cognition Dietary Supplement: Vitamin C Phase 4

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.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 24 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double (Investigator, Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: Cognitive and Cerebral Blood Flow Effects of Vitamin C
Study Start Date : January 2010
Actual Primary Completion Date : September 2010
Actual Study Completion Date : September 2010

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Vitamin C

Arm Intervention/treatment
Placebo Comparator: placebo Dietary Supplement: Vitamin C
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.

Experimental: Vitamin C Dietary Supplement: Vitamin C
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.

Primary Outcome Measures :
  1. Endothelial function (using cerebral blood flow as a proxy measurement as measured by TCD and NIRS. [ Time Frame: ~100 mins ]

Secondary Outcome Measures :
  1. Cognitive performance [ Time Frame: ~50 mins ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 35 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Male/Female,
  • 18-35

Exclusion Criteria:

  • 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,
  • a history of/current head trauma,
  • learning difficulties,
  • ADHD and
  • migraines.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01055418

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United Kingdom
Brain, Performance and Nutrition Research Centre, Northumbria University
Newcastle upon Tyne, Tyne and Wear, United Kingdom, NE1 8ST
Sponsors and Collaborators
Northumbria University
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Study Director: David Kennedy Northumbria University
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Responsible Party: David Kennedy, Professor, Northumbria University Identifier: NCT01055418    
Other Study ID Numbers: 24AD1
First Posted: January 25, 2010    Key Record Dates
Last Update Posted: May 3, 2013
Last Verified: May 2013
Keywords provided by David Kennedy, Northumbria University:
Vitamin C
Cognitive performance
Cerebral blood flow
Trans cranial doppler
Near infrared spectroscopy
Additional relevant MeSH terms:
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Ascorbic Acid
Growth Substances
Physiological Effects of Drugs
Molecular Mechanisms of Pharmacological Action
Protective Agents