Effect of Oral Caffeine and L-Citrulline Supplementation on Arterial Function in Healthy Males

NCT02214290 | Completed Results

• 1 other identifier: HSC2013.10514
• Study Type: interventional
• Target: 16
• Locations: 0 countries
• Sites: N/A

Brief Summary

Caffeine is an exceedingly popular and consumed pharmacological agent. Although caffeine is primarily consumed from coffee and tea beverages, it is also available in other forms such as sodas, energy drinks, tablets and capsules. Nevertheless, caffeine acutely increases brachial and aortic systolic blood pressure (BP) and arterial stiffness. Arterial stiffness is an independent predictor of cardiovascular disease (CVD) and assessed through pulse wave velocity (PWV). Interestingly, previous studies have proposed that caffeine may increase aortic BP through increases in aortic PWV and augmentation index (AIx), a measurement of wave reflection. Yet, these effects were seen in middle-aged adults with treated hypertension and a wide age range. Therefore, it is imperative to consider that caffeine may cause different effects in young normotensive individuals than in older adults independently of BP levels. Importantly, oral supplementation of the amino-acid, L-citrulline has been shown to enhance the bioavailability of L-arginine levels and nitric oxide (NO) production and, therefore, improve arterial function. L-citrulline supplementation for 7 days given at 6 g/day has shown to increase NO levels while improving PWV. Previous studies by our group also demonstrated that L-citrulline supplementation reduces the BP response to cold exposure; a condition with an increased vasoconstriction. Therefore, the acute effects of caffeine on central and peripheral PWV and BP in healthy young men are yet to be fully evaluated. We hypothesized that acute caffeine intake would increase peripheral and aortic BP and PWV and that L-citrulline supplementation would attenuate the effects induced by acute caffeine ingestion.

Conditions

Hypertension; Healthy

Keywords

Cardiovascular; Caffeine; L-citrulline; Arterial Function; Hemodynamics; Blood Pressure; Pulse Wave Velocity; Pulse Wave Analysis

Outcome Measures

Primary Outcomes (1)

• Aortic Blood Pressure

  Aortic blood pressure at rest and 30 minutes after acute ingestion of 200 mg of caffeine before and after 7 days of either 6g/day of Citrulline or 6 g/day of Placebo.

  Baseline and Day 7 (Calculated change between rest and 30 minutes post-caffeine ingestion at these time points)

Secondary Outcomes (2)

• Changes in Reflected Wave Pressure (P2)

  Baseline and Day 7 (Calculated change between rest and 30 minutes post-caffeine ingestion at these time points)

• Changes in Femoral-ankle Pulse Wave Velocity After 7 Days of Either L-Citrulline or Placebo (6g/Day)

  Baseline and Day 7 (Calculated change between rest and 30 minutes post-caffeine ingestion at these time points)

Study Arms (3)

Caffeine

ACTIVE COMPARATOR

200 mg caffeine tablet produced by CVS Pharmacy, USA

Drug: Caffeine

Placebo

PLACEBO COMPARATOR

Placebo pill produced by NOW FOODS, USA

Drug: Placebo

L-citrulline

EXPERIMENTAL

L-citrulline capsule (750 mg) provided by NOW FOODS

Dietary Supplement: L-citrulline

Interventions

Caffeine DRUG

A 200 mg caffeine tablet was given to subject to examine the drugs effect on arterial function.

Also known as: Caffeine tablet (CVS Pharmacy)

Caffeine

Placebo DRUG

A 750 mg placebo capsule (maltodextrin) was given to subjects to examine the effect of the drug on arterial function.

Also known as: Placebo from NOW FOODS, USA

Placebo

L-citrulline DIETARY_SUPPLEMENT

L-citrulline was used to examine the effect of the supplement on arterial function.

Also known as: L-citrulline (750 mg/capsule)

L-citrulline

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Young healthy males
• Non smoker
• Non endurance trained athlete
• No previous history of cardiovascular disease

You may not qualify if:

• Female
• Blood pressure greater than 160/100
• Smoker

Sponsors & Collaborators

• Florida State University: lead

MeSH Terms

Conditions

Hypertension

Interventions

Caffeine; Citrulline

Condition Hierarchy (Ancestors)

Vascular Diseases; Cardiovascular Diseases

Intervention Hierarchy (Ancestors)

Xanthines; Alkaloids; Heterocyclic Compounds; Purinones; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring; Amino Acids, Diamino; Amino Acids; Amino Acids, Peptides, and Proteins

Results Point of Contact

• Title: Dr. Arturo Figueroa
• Organization: Texas Tech University

arturo.figueroa@ttu.edu

8068345587

Study Officials

• Arturo Figueroa, M.D. Ph.D

  Florida State University

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: August 4, 2014
• First Posted: August 12, 2014
• Study Start: September 1, 2012
• Primary Completion: March 1, 2014
• Study Completion: March 1, 2014
• Last Updated: December 29, 2020
• Results First Posted: December 29, 2020

Record last verified: 2020-10

Data Sharing

• IPD Sharing: Will not share