The Effects of Watermelon Juice Supplementation on Postprandial Vascular Endothelial Function (WMJ)

July 29, 2024 updated by: Timothy Allerton, PhD, Pennington Biomedical Research Center

The Effects of Watermelon Juice Supplementation on Postprandial Vascular Endothelial Function and Blood Flow During Hyperglycemia: A Pilot Study

The purpose of this study is to test if watermelon juice supplementation improves vascular dysfunction experience during hyperglycemia.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The objective of this pilot study is to determine the potential for watermelon juice to attenuate the reduction postprandial endothelial function and skeletal muscle microvascular blood flow (MVBF) experienced during hyperglycemia.

The investigators will attempt to answer the following hypotheses:

Hypothesis 1: Watermelon juice supplementation will attenuate the reduction in endothelial dysfunction and microvascular blood flow during an oral glucose challenge.

Hypothesis 2: Watermelon juice will increase L-arginine bioavailability during hyperglycemia and correlate with improved vascular response.

Exploratory Aim: The postprandial period is defined by increased sympathetic nervous system activity (vasoconstriction) and NO• mediated vasodilation. Heart rate variability (HRV) is a measurement of the balance of parasympathetic to sympathetic activity. The investigators will measure HRV during the oral glucose challenge to interrogate the possibility that watermelon juice can modulate the balance of blood vessel constriction and relaxation during an oral glucose

Procedures Involved

There will be 1 screening visit, and 2 outpatient visits. Participants will consume watermelon juice or placebo for 2 weeks. The washout period will last 2 weeks prior to the cross-over to the opposite condition. Participants visits will be conducted at the Vascular and Resting Metabolism Lab located in the department of kinesiology at LSU.

Screening Visit

Participants will undergo consenting and fasting blood draws to measure glucose, lipids, and CBC. Vital signs (blood pressure, body weight, body composition (DXA), heart rate, etc) will be measured. For DXA procedure participants will undergo a whole body scan lasting approximately 10 minutes. Participants will remove all metal objects from their body and lie down on the table. The legs will be secured together using two Velcro straps. The participant will be instructed to remain completely still during the scan. Randomization will be performed to allocate the study participant for their initial group assignment to either the watermelon juice group or placebo. The initial six participants will be assigned treatment A for phase 1 and treatment B for phase 2, thereafter the following 6 will be assigned treatment B first then treatment A. The remaining participant will be randomly assigned either treatment A or B in a counterbalanced fashion.

Daily Juice Drop-in visits

Since the required supplementation duration is 14 days participants will be provided with 2 days (Saturday and Sunday) worth of watermelon juice or placebo to account for days when the LSU AG Center will not be open. To allow for scheduling conflicts and unforeseen circumstances a 3 day period of supplementation less then or greater than the 14 periods will be permitted. Participants will also be provided with juice or placebo for anticipated instances where they cannot be on campus. In order to monitor compliance participants will be asked return the juice container for the days where juice was consumed off premises.

Visit 2 and 3: Oral Glucose Challenge - Postprandial FMD and MVBF

Participants will arrive in morning at 6:00am fasted for 10-hours. Body composition will be measured by DXA. Next, participants will rest for 30 minutes in the supine positing while wearing a heart rate monitor (Zephyr, Bioharness) to measure heart rate and heart rate variability. Resting metabolic rate will be measured via indirect calorimetry for 20 minutes. Then fasting measures of blood glucose, FMD (ultrasound) and MVBF (near-infrared spectroscopy) will be taken followed by ingestion of 75 g of glucose (glucola). An IV line will be placed in the participants arm vein for blood draw purposes and will remain there throughout the testing. A blood sample will be drawn, and then the participant will drink a sugar solution consisting of 75 grams of glucose. Blood will be drawn at specific times after the participant consumes the drink. Each blood sample will be about 1 tablespoon. (6 tablespoons total for the test). During the IV procedure, a small amount of the participant's own blood (less than 1 teaspoon) will immediately be returned into the participants vein through the IV after each specimen is collected. Blood will be drawn at minute 15, 30, 60, 90, 120 minutes. Postprandial measurements of FMD and MVBF will be taken at 30, 60, 90, and 120 minutes.

Study Type

Interventional

Enrollment (Actual)

18

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Louisiana
      • Baton Rouge, Louisiana, United States, 70808
        • Pennington Biomedical Research Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 40 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Capable and willing to give written informed consent and understand inclusion and exclusion criteria.
  2. 18-40 years of age
  3. BMI between 18-29.9 kg/m2
  4. Willing to allow researchers to draw blood and conduct imaging (DXA) for research purposes.

Exclusion Criteria:

  1. Evidence or self-reported history of type 1 or 2 diabetes mellitus
  2. Self-reported family history of type 2 diabetes (first degree relative with type 2 diabetes)
  3. Evidence or self-report history of deep vein thrombosis, pulmonary embolism, cardiovascular, peripheral vascular, cerebral vascular, pulmonary, or renal disease
  4. Allergy to watermelon

  5. Use of medication known to influence study outcomes, such as:

    1. Insulin
    2. Anti-diabetics (metformin)
    3. Corticosteroids
    4. Beta-blockers
    5. Anti-coagulates

  6. Use of supplements known to influence study outcomes, such as;

    1. Beta-alanine
    2. L-arginine
    3. L-citrulline
  7. Active smoking

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Watermelon juice
The study participants consumed 500 ml of 100% watermelon juice for two weeks
Dietary supplement: Watermelon Juice
100% Watermelon Juice
Placebo Comparator: Placebo
The study participants consumed a watermelon flavored, fructose matched control
Dietary supplement: Watermelon Juice
100% Watermelon Juice

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Endothelial Function
Time Frame: Two weeks
Flow mediated dilation
Two weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Postprandial Blood Flow
Time Frame: Two weeks
microvascular blood flow
Two weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Pennington Biomedical Research Center

Investigators

  • Principal Investigator: Timothy D Allerton, PhD, Pennington Biomedical Research Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 12, 2019

Primary Completion (Actual)

March 20, 2020

Study Completion (Actual)

March 20, 2020

Study Registration Dates

First Submitted

September 15, 2019

First Submitted That Met QC Criteria

September 15, 2019

First Posted (Actual)

September 17, 2019

Study Record Updates

Last Update Posted (Actual)

July 30, 2024

Last Update Submitted That Met QC Criteria

July 29, 2024

Last Verified

July 1, 2024

More Information

Terms related to this study

Other Study ID Numbers

  • PBRC 2019-024

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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