Cognitive and Cerebral Blood Flow Effects of Vitamin C

Cognition Clinical Trial

Official title:

Cognitive and Cerebral Blood Flow Effects of Vitamin C

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01055418
• Other study ID #: 24AD1
• Status: Completed
• Phase: Phase 4
• First received: January 22, 2010
• Last updated: May 1, 2013
• Start date: January 2010
• Est. completion date: September 2010

Study information

• Verified date: May 2013
• Source: Northumbria University
• Contact: n/a
• Is FDA regulated: No
• Health authority: United Kingdom: Research Ethics Committee
• Study type: Interventional

Clinical 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. 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 24
• Est. completion date: September 2010
• Est. primary completion date: September 2010
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 18 Years to 35 Years

Eligibility

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.

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Investigator, Outcomes Assessor), Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Cognition
• Endothelial Function

Intervention

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.

Locations

Country	Name	City	State
United Kingdom	Brain, Performance and Nutrition Research Centre, Northumbria University	Newcastle upon Tyne	Tyne and Wear

Sponsors (1)

Lead Sponsor	Collaborator
Northumbria University

Country where clinical trial is conducted

United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Endothelial function (using cerebral blood flow as a proxy measurement as measured by TCD and NIRS.		~100 mins	No
Secondary	Cognitive performance		~50 mins	No