Evaluation of Sports Supplements on Blood Flow

• ClinicalTrials.gov Identifier: NCT04278053
• Recruitment Status: Completed
• First Posted: February 20, 2020
• Last Update Posted: May 24, 2022
• Sponsor: University of Arkansas, Fayetteville
• Information provided by (Responsible Party): Michelle Gray, University of Arkansas, Fayetteville

Study Description

Brief Summary:

Many athletes seek to increase their plasma (blood) nitric oxide content prior to exercise in order to augment vasodilation. Increased vasodilation during exercise, especially high intensity resistance training, allows for more blood flow to muscle tissues, which may give the athlete benefits such as increased work capacity and acute muscle hyperemia, which is commonly referred to as muscle pump. Pre-workout supplements are typically taken 30 minutes to 1 hour prior to the onset of exercise, so the current investigation seeks to determine if citrulline malate or nitrosigine can effect vasodilation within 1 hour of supplementation, and if so, which supplement is more effective. Based on previous findings, we hypothesize that a certain exercise intensity needs to be present for citrulline malate and nitrosigine to have an effect, so a change may not be observable at rest.

Condition or disease	Intervention/treatment	Phase
Determine the Effects of Nitrosigine and Citrulline-malate on Flow-mediated Dilation Among Young Adults	Dietary Supplement: inositol-stabilized arginine silicate	Not Applicable

Detailed Description:

Data collection will be conducted by qualified research staff and students at the University of Arkansas Exercise Science Research Center (ESRC). Upon contact with the research team, a medical/health questionnaire will be sent via email to the subject. This will be the initial screening tool to determine if the subject qualifies for the project. The subjects must meet the inclusion and none of the exclusion criteria in order to qualify for the study. Participants will be instructed to do the following the day of data collection: 1. No caffeine, stimulants, or blood thinners (such as ibuprofen, advil, aspirin, warfarin, clopidogrel, etc.) 24 hours prior to testing. 2. Wear comfortable clothes (short sleeve top). 3. Take all medication as normal (aside from those mentioned in #1). Participant testing will be conducted as follows: participant arrives at ESRC; height, weight, blood pressure, and complete questionnaires (electronically): medical history, 24-hour dietary recall, International Physical Activity Questionnaire (IPAQ). IPAQ is a standardized questionnaire used to evaluate an individual's level of physical activity in their daily life. After completing all surveys, the subject will be asked to lie in a supine position for 15 minutes, then they will have the diameter of the brachial artery (medial side of upper arm) assessed with ultrasound (GE Logiq e). Ultrasound is a non-invasive way of determining the diameter of arteries. A total of 10 measurements will be taken of the brachial artery. After the initial 10 measurements (~3-5 minutes), flow-mediated dilation (FMD) will be performed. Flow mediated dilation will be performed with a Hokanson rapid cuff inflator. The cuff (blood pressure cuff) will be position on the forearm (just above the wrist) and will be inflated to 250-300mmHg for a period of 5 minutes to restrict blood flow. After the 5-minute inflation period, the cuff will deflate and vessel diameter will be re-assessed (10 additional trails). Following the initial FMD assessment, one of three supplements will be consumed: citrulline-malate (8 g), Nitrosigine (1.5 g), or placebo (8 g Dextrose). After consumption, participants will remain in ESRC for 60 minutes to allow for digestion of the substance. Following the 60-minute absorption period, FMD will be re-assessed.

Study Design

• Study Type: Interventional (Clinical Trial)
• Actual Enrollment: 24 participants
• Allocation: Randomized
• Intervention Model: Crossover Assignment
• Intervention Model Description: Randomized, double-blind, crossover design
• Masking: Double (Participant, Investigator)
• Masking Description: Both the participants and the researchers were blinded to the supplements until all data collection had been completed.
• Primary Purpose: Other
• Official Title: Effects of Nitrosigine on Flow-Mediated Dilation Among Young Adults
• Actual Study Start Date: October 15, 2018
• Actual Primary Completion Date: May 8, 2019
• Actual Study Completion Date: May 8, 2019

Arms and Interventions

Arm	Intervention/treatment
Experimental: Nitrosigine supplementation; Ultrasound is a non-invasive way of determining the diameter of arteries. A total of 10 measurements will be taken of the brachial artery. After the initial 10 measurements (~3-5 minutes), flow-mediated dilation (FMD) was performed. Flow mediated dilation was performed with a Hokanson rapid cuff inflator. The cuff (blood pressure cuff) was position on the forearm (just above the wrist) and was inflated to 250-300mmHg for a period of 5 minutes to restrict blood flow. After the 5-minute inflation period, the cuff was deflated and vessel diameter was re-assessed (10 additional trails). Following the initial FMD assessment, Nitrosigine (1.5 g) was provided in an 8 ounce solution with a cherry flavoring to mask taste. After consumption, participants remained in ESRC for 60 minutes to allow for digestion of the substance. Following the 60-minute absorption period, FMD was re-assessed.	Dietary Supplement: inositol-stabilized arginine silicate; Participants were asked to complete the experimental protocol in a 2-hour fasted state. Each participant's brachial artery FMD was assessed twice during each trial, once before supplement ingestion, and again 60 minutes post-ingestion. Male participants were required to wait for a minimum of seven days between trials as a supplement washout period. Female participants reported for supplement trials outside of their follicular phase of the menstrual cycle so that results were not confounded by changes in serum estradiol, which can significantly attenuate flow-mediated dilation. Sixty minutes after supplement consumption, each participant was asked which supplement they thought they had consumed. Participants were also asked whether they experienced any adverse side effects.
Experimental: Citrulline-Malate supplementation; Ultrasound is a non-invasive way of determining the diameter of arteries. A total of 10 measurements will be taken of the brachial artery. After the initial 10 measurements (~3-5 minutes), flow-mediated dilation (FMD) was performed. Flow mediated dilation was performed with a Hokanson rapid cuff inflator. The cuff (blood pressure cuff) was position on the forearm (just above the wrist) and was inflated to 250-300mmHg for a period of 5 minutes to restrict blood flow. After the 5-minute inflation period, the cuff was deflated and vessel diameter was re-assessed (10 additional trails). Following the initial FMD assessment, Citrulline-Malate (8 g) was provided in an 8 ounce solution with a cherry flavoring to mask taste. After consumption, participants remained in ESRC for 60 minutes to allow for digestion of the substance. Following the 60-minute absorption period, FMD was re-assessed.	Dietary Supplement: inositol-stabilized arginine silicate; Participants were asked to complete the experimental protocol in a 2-hour fasted state. Each participant's brachial artery FMD was assessed twice during each trial, once before supplement ingestion, and again 60 minutes post-ingestion. Male participants were required to wait for a minimum of seven days between trials as a supplement washout period. Female participants reported for supplement trials outside of their follicular phase of the menstrual cycle so that results were not confounded by changes in serum estradiol, which can significantly attenuate flow-mediated dilation. Sixty minutes after supplement consumption, each participant was asked which supplement they thought they had consumed. Participants were also asked whether they experienced any adverse side effects.
Placebo Comparator: Placebo; Ultrasound is a non-invasive way of determining the diameter of arteries. A total of 10 measurements will be taken of the brachial artery. After the initial 10 measurements (~3-5 minutes), flow-mediated dilation (FMD) was performed. Flow mediated dilation was performed with a Hokanson rapid cuff inflator. The cuff (blood pressure cuff) was position on the forearm (just above the wrist) and was inflated to 250-300mmHg for a period of 5 minutes to restrict blood flow. After the 5-minute inflation period, the cuff was deflated and vessel diameter was re-assessed (10 additional trails). Following the initial FMD assessment, dextrose (8 g) was provided in an 8 ounce solution with a cherry flavoring to mask taste. After consumption, participants remained in ESRC for 60 minutes to allow for digestion of the substance. Following the 60-minute absorption period, FMD was re-assessed.	Dietary Supplement: inositol-stabilized arginine silicate; Participants were asked to complete the experimental protocol in a 2-hour fasted state. Each participant's brachial artery FMD was assessed twice during each trial, once before supplement ingestion, and again 60 minutes post-ingestion. Male participants were required to wait for a minimum of seven days between trials as a supplement washout period. Female participants reported for supplement trials outside of their follicular phase of the menstrual cycle so that results were not confounded by changes in serum estradiol, which can significantly attenuate flow-mediated dilation. Sixty minutes after supplement consumption, each participant was asked which supplement they thought they had consumed. Participants were also asked whether they experienced any adverse side effects.

Outcome Measures

Primary Outcome Measures :

1. Vasodilation [ Time Frame: 60 minutes ]
   Amount of brachial vasodilation caused by supplementation as measured by flow-mediated dilation and ultrasound

Eligibility Criteria

• Ages Eligible for Study: 18 Years to 29 Years (Adult)
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

Criteria

Inclusion Criteria:

• Healthy, regularly exercising young adults

Exclusion Criteria:

• hypertension, metabolic disorders, previous consumption of pre-workout supplements 6 months prior to study, prescriptions medications known to effect the vasodilatory response.

Contacts and Locations

Locations

United States, Arkansas

University of Arkansas

Fayetteville, Arkansas, United States, 72701

Sponsors and Collaborators

University of Arkansas, Fayetteville

Investigators

• Principal Investigator: Michelle Gray, Ph.D; University of Arkansas

More Information

• Responsible Party: Michelle Gray, Associate Professor - Exercise Science, University of Arkansas, Fayetteville
• ClinicalTrials.gov Identifier: NCT04278053
• Other Study ID Numbers: 1812163576
• First Posted: February 20, 2020
• Last Update Posted: May 24, 2022
• Last Verified: May 2022

Individual Participant Data (IPD) Sharing Statement:

• Plan to Share IPD: No

• Studies a U.S. FDA-regulated Drug Product: No
• Studies a U.S. FDA-regulated Device Product: No

Keywords provided by Michelle Gray, University of Arkansas, Fayetteville:

flow-mediated dilation; vasodilation; Nitrosigine; Citrulline-Malate

Additional relevant MeSH terms:

Dilatation, Pathologic; Pathological Conditions, Anatomical; Inositol; Vitamin B Complex; Vitamins; Micronutrients; Physiological Effects of Drugs