Role of Flavanols in Exercise and Aging

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Robert M. Brothers, University of Texas at Austin
ClinicalTrials.gov Identifier:
NCT01557738
First received: March 8, 2012
Last updated: June 24, 2014
Last verified: May 2014
  Purpose

It has well known that diets rich in fruits, vegetables and cocoa products are associated with positive health benefits and these positive effects have been shown to be due to compounds they contain called flavanols. Flavanols have been shown to exert their positive effects by indirectly increasing nitric oxide (NO) bioavailability. NO is a potent vasodilator that is believed to play a role in increasing blood flow to active muscle during exercise. This regulatory process is impaired with healthy aging. The underlying premise to this study is that if NO bioavailability can be increased following flavanol ingestion, will there be a restoration of blood flow during exercise in older individuals? Accordingly, the first part of this research project will compare the acute vascular effects of flavanol ingestion between a young and old group. The investigators have hypothesized that both groups will show an improvement in blood flow to active muscle during exercise, though the magnitude of the change will be greater in the older group. The second part of this project will look at the effects of 4 weeks of daily flavanol ingestion in the old group. The investigators hypothesize that subjects will demonstrate an improvement in blood flow to active muscle during exercise after the 4 week intervention and that the magnitude of the change will be greater than the acute effects. Findings from this proposal will provide evidence for the efficacy of flavanols to be used (as a simple and safe lifestyle intervention) to reverse or combat impaired blood flow regulation in older individuals.


Condition Intervention
Aging
Dietary Supplement: High Flavanol Trial
Dietary Supplement: Low Flavanol Trial
Dietary Supplement: High Flavanol Trial; long-term
Dietary Supplement: Low Flavanol Trial; long-term effects

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Basic Science
Official Title: Acute and Long-term Effects of Dietary Flavanols on Local Control of Skeletal Muscle Blood Flow During Exercise in Young and Old Humans

Resource links provided by NLM:


Further study details as provided by University of Texas at Austin:

Primary Outcome Measures:
  • Change in femoral blood flow during exercise following flavanol consumption [ Time Frame: During knee extension exercise, change from baseline in blood flow 2 hours post flavanol ingestion ] [ Designated as safety issue: No ]
    Blood flow regulation to active muscles during knee extension exercise can be assessed by using ultrasound to measure blood flow in the femoral artery. This will be done before and after stimulation of the sympathetic nervous system. A baseline value will be obtained and then the measurement will be performed again 2 hours after flavanol ingestion.


Secondary Outcome Measures:
  • Change in flow-mediated dilation (FMD) following flavanol consumption [ Time Frame: Change from baseline in FMD 2 hours post flavanol ingestion ] [ Designated as safety issue: No ]
    Flow-mediated dilation is commonly used as an index of nitric oxide bioavailability. Nitric oxide is believed to play a role in blood flow regulation during exercise. A baseline value will be obtained and then the measurement will be performed again 2 hours after flavanol ingestion.


Enrollment: 20
Study Start Date: December 2012
Study Completion Date: April 2014
Primary Completion Date: April 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Acute effects of flavanol consumption
The outcome measurements will be made on all study participants before and 2 hours after consumption of the high flavanol beverage.
Dietary Supplement: High Flavanol Trial
The experimental trial (high flavanol content) will involve the consumption of a beverage containing about 1000mg of cocoa flavanols.
Placebo Comparator: Low Flavanol Trial; acute effects
Once again, the outcome measurements will be made on all study participants before and 2 hours after consumption of the low flavanol beverage.
Dietary Supplement: Low Flavanol Trial
The placebo trial (low flavanol content) will involve the consumption of a beverage containing 75 mg of cocoa flavanols.
Experimental: Long-term effects of flavanol consumption
Only those study participants over 60 years of age will continue with this arm of the trial. The same outcome measures will be performed following 4 weeks of daily consumption of a high flavanol beverage.
Dietary Supplement: High Flavanol Trial; long-term
The experimental trial (high flavanol content) will involve the daily consumption of a beverage containing about 1000mg of cocoa flavanols for 4 weeks. Subjects will be provided with 28 packets of the beverage to take home with them.
Placebo Comparator: Low Flavanol Trial; long-term effects
Only those study participants over 60 years of age will continue with this arm of the trial. The same outcome measures will be performed following 4 weeks of daily consumption of a low flavanol beverage.
Dietary Supplement: Low Flavanol Trial; long-term effects
The placebo trial (low flavanol content) will involve the daily consumption of a beverage containing 75 mg of cocoa flavanols for 4 weeks. Subjects will be provided with 28 packets to take home with them.

  Eligibility

Ages Eligible for Study:   18 Years to 80 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Males and Females between 18 - 30 years old
  • Males and Females between 60 - 80 years old

Exclusion Criteria:

  • cardiovascular and/or microvascular disease
  • blood clotting disorder
  • pregnant lady
  • current smoker (or regularly smoked within last year)
  • a history of an adverse reaction to cold
  • taking medications known to effect the autonomic nervous system
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01557738

Locations
United States, Texas
University of Texas at Austin: Environmental and Autonomic Physiology Laboratory
Austin, Texas, United States, 78712
Sponsors and Collaborators
University of Texas at Austin
Investigators
Principal Investigator: Michelle Harrison, M.A. University of Texas at Austin
  More Information

No publications provided

Responsible Party: Robert M. Brothers, Assistant Professor, University of Texas at Austin
ClinicalTrials.gov Identifier: NCT01557738     History of Changes
Other Study ID Numbers: 2012-02-0114
Study First Received: March 8, 2012
Last Updated: June 24, 2014
Health Authority: United States: Institutional Review Board

Keywords provided by University of Texas at Austin:
Exercise
Blood Flow
Nitric Oxide
Aging
Antioxidant
Flavanol
Young (18-30 yrs)
Aging (60 - 80 yrs)

ClinicalTrials.gov processed this record on August 21, 2014