Bioactive Compounds in Watermelon Modulating Oxidative Stress and Inflammation in Elders (MOXIE)

May 16, 2022 updated by: Amy Ellis, University of Alabama, Tuscaloosa

Bioactive Compounds in Watermelon Modulating Oxidative Stress and Inflammation in Elders: The MOXIE Study

Watermelon is the only food with a unique combination of amino acids and antioxidants that may reduce artery stiffness. However, only 27% of older adults meet the daily recommendation for fruit intake. Because it tastes good and is convenient and easy to consume, watermelon juice is an innovative and impactful intervention to help elders easily meet recommendations for fruit servings. If effective, this intervention would be a simple, inexpensive way to combat cardiovascular diseases (CVD). Results will advance science by providing a better understanding whether four-week consumption of 100% watermelon juice may impact measures of vascular health and inflammation in postmenopausal women.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Purpose and Objectives:

Vascular endothelial dysfunction is an early independent predictor of cardiovascular diseases (CVD), the leading cause of death for women ages 60 and older in the United States1. It is well-known that age-related decreases in vascular endothelial function are partially due to increases in oxidative stress and inflammation.In attempts to combat CVD, previous intervention studies have investigated provision of isolated bioactive food compounds (BFC) in supplemental form. For example, purified lycopene has been shown to decrease oxidative stress, and our previous work supports the supplemental use of glutamine and arginine in improving vascular endothelial function of older adults. Arginine is a precursor for the vasodilatory molecule nitric oxide (NO), and both glutamine and arginine have been shown to attenuate inflammation. Thus, if supplemented together, these compounds would be expected to exert synergist mechanistic effects that improve vascular function.

Watermelon is one of the richest sources of lycopene, and it is among the greatest plant sources of arginine and glutamine. Watermelon also provides high amounts of citrulline (a precursor of arginine) along with the antioxidant ascorbic acid, which enhances the antioxidant and anti-inflammatory effects of carotenoids such as lycopene in biological samples. To date, clinical studies evaluating the potential synergy of these compounds provided by the whole food are lacking on mechanistic and clinical outcomes of CVD. The effects of watermelon supplementation on robust measures of vascular function, inflammation, and oxidative stress in women ages 60 and older are unknown. This study will evaluate the possible impact of multiple bioactive compounds in the natural food matrix of watermelon in order to fully characterize their potential synergy and their influence on CVD risk. Specifically, our proposed study seeks to evaluate the influence of bioactive compounds in 100% watermelon juice, a convenient serving alternative to fresh fruit, using a randomized, double-blind placebo-controlled trial with a crossover design.

Specific Aims:

  1. Mechanistic: To determine whether community-dwelling, non-obese women ages 55-69 consuming two 12-ounce servings of 100% watermelon juice per day versus placebo for four weeks will demonstrate:

    1. increases in circulating levels of serum lycopene, citrulline, and arginine using ultra high performance liquid chromatography with photodiode array detector (UPLC-PDA).
    2. improvement in antioxidant status as assessed by the oxygen radical absorbance capacity assay (ORAC) of whole and deproteinated serum
    3. decreases in circulating biomarkers of inflammation Hypotheses: Four-week dietary supplementation with 100% watermelon juice will result in increased antioxidant capacity and decreased inflammation, related to increased serum lycopene, citrulline, and arginine

  2. Clinical: To determine whether community-dwelling, women ages 55-69 consuming two 12-ounce servings of 100% watermelon juice per day versus placebo for four weeks will exhibit:

    1. improved vascular endothelial function as assessed by flow-mediated dilation (FMD) and decreased arterial stiffness as assessed by pulse wave analysis (PWA)
    2. decreased low density lipoprotein (LDL) oxidation as assessed by enzyme immunoassay Hypotheses: Four-week dietary supplementation with 100% watermelon juice will result in improved vascular endothelial function, decreased arterial stiffness, and decreased LDL oxidation.

Study Type

Interventional

Enrollment (Actual)

21

Phase

  • Not Applicable

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

55 years to 69 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • Ambulatory
  • Female
  • Age 55-69 years
  • Body mass index 18.5 - 29.9 kg/m2 (non-obese)

Exclusion Criteria:

  • Food allergy to watermelon
  • History of hypotension, chronic hypertension, chronic kidney disease, diabetes, previous cardiac events or procedures, phenylketonuria
  • Smoking or other tobacco use
  • Use of anticoagulant medications, cholesterol-lowering medications, blood-pressure medications, vasodilatory dietary supplements (garlic, fish oil), or dietary supplements containing lycopene, ascorbic acid, L-glutamine, L-arginine, or L-citrulline
  • Weight change > 10% in the previous year

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: PREVENTION
  • Allocation: NON_RANDOMIZED
  • Interventional Model: CROSSOVER
  • Masking: TRIPLE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
ACTIVE_COMPARATOR: Consumption of 100% watermelon juice
Consumption of two 12-ounce doses of pasteurized 100% watermelon juice for a four-week period
Dietary supplement: 100% watermelon juice
Participants drank two 12-ounce servings of 100% watermelon juice per day for a four-week period.
PLACEBO_COMPARATOR: Consumption of a placebo beverage
Consumption of a placebo beverage with comparable sugar content, pH, taste, texture, and color for a four-week period
Other: Placebo beverage
Participants drank two 12-ounce servings of a placebo beverage per day for a four-week period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change From Baseline in Serum Levels of Lycopene at 4 Weeks
Time Frame: Baseline and 4 Weeks
Lycopene determined by ultra high performance liquid chromatography with photodiode array detector (UPLC-PDA).
Baseline and 4 Weeks
Change in Vascular Endothelial Function at 4 Weeks
Time Frame: Baseline and 4 weeks
Determined by brachial artery flow-mediated dilation (FMD). FMD uses ultrasound technology to quantify changes in brachial artery diameter in response to hyperemia. A blood pressure cuff was placed distal to the brachial artery of the right arm with the participant supine and rested. Pre-inflation diameter was recorded for one minute, and the cuff was inflated to 50 mmHg above resting SBP for five minutes. Then, images were recorded for 120 seconds after cuff deflation. Peak diameter was determined as an average of the five highest measurements over five seconds post-deflation. FMD was expressed as the percentage increase in peak diameter.
Baseline and 4 weeks
Change in Arterial Stiffness at 4 Weeks
Time Frame: Baseline and 4 weeks
Determined by pulse wave velocity (PWV). A cuff-based system was used to measure brachial oscillometric pressure waveforms and generate central pressure curves by propriety algorithms. PWV was quantified as the rate at which a pulse wave moves down a vessel.
Baseline and 4 weeks

Collaborators and Investigators

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

Sponsor

University of Alabama, Tuscaloosa

Investigators

  • Principal Investigator: Kristi Crowe-White, PhD, RD, University of Alabama at Birmingham

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)

February 16, 2016

Primary Completion (ACTUAL)

May 12, 2018

Study Completion (ACTUAL)

May 12, 2018

Study Registration Dates

First Submitted

July 24, 2018

First Submitted That Met QC Criteria

August 7, 2018

First Posted (ACTUAL)

August 10, 2018

Study Record Updates

Last Update Posted (ACTUAL)

May 17, 2022

Last Update Submitted That Met QC Criteria

May 16, 2022

Last Verified

May 1, 2022

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 16MCPRP27260233

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

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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