Effect of Watermelon on Cardiometabolic Health

NCT07006636 | Not Yet Recruiting

• 1 other identifier: IRB-25-1126
• Study Type: interventional
• Target: 22
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this study is to determine whether consumption of 355 ml of watermelon juice will:

1. 1.improve cardiovascular and overall metabolic health markers like blood pressure, heart rate, stiffness/flexibility of arteries (blood vessels), blood sugar, cholesterol), and gut hormones
2. 2.contribute to the body's ability to protect itself from the potential cell damage caused by harmful chemical compounds (produced when skin is exposed to ultraviolet (UV) B light, for example). This will be evaluated by measuring how resistant skin is to the damage from UVB light exposure, as well as several markers of bodily stress blood and urine.

Conditions

Cardiometabolic Health Indicators; Whole-body Antioxidant Capacity

Outcome Measures

Primary Outcomes (3)

• Postprandial blood pressure

  To determine the acute and chronic effects of WMJ consumption on cardiometabolic health, specifically focusing on postprandial blood pressure. Previous studies showed that watermelon extract improved blood pressure management in subjects with prehypertension and hypertension and reduced arterial stiffness in postmenopausal women. Postprandial blood pressure response is recently identified to be the most sensitive postprandial clinical feature in predicting subclinical atherosclerosis. However, no study has evaluated the effect of watermelon on postprandial blood pressure. Blood pressure will be measured in mm/Hg.

  Baseline and Week 4

• Postprandial heart rate

  Will be measured in beats per minute.

  Baseline and 4 weeks.

• Postprandial pulse wave velocity

  Will be measured in meters/second.

  Baseline and 4 weeks.

Secondary Outcomes (6)

• Postprandial nitric oxide (NO)

  Baseline and 4 weeks.

• Postprandial glucose

  Baseline and 4 weeks.

• Postprandial blood lipids/lipoproteins (LDL cholesterol, HDL cholesterol, total cholesterol, triglycerides).

  Baseline and 4 weeks.

• Postprandial insulin

  Baseline and 4 weeks.

• Postprandial C-peptide

  Baseline and 4 weeks.

Other Outcomes (2)

• Minimal Erythema Dose (MED)

  Baseline and week 4.

• Blood and urinary malondialdehyde (MDA) concentrations

  Baseline and 4 weeks.

Study Arms (2)

Watermelon Juice + liquid meal test at baseline

EXPERIMENTAL

Acute (postprandial) as well as chronic (4 weeks) effects of WMJ consumption will be evaluated. To evaluate acute effects participants will consume a liquid meal test together with WMJ at the beginning of the intervention phase. In addition, the same liquid meal test will be consumed with only WMJ at the end of the intervention phase to assess whether drinking the juice for 4 weeks prior had any effects on postprandial responses.

Other: Watermelon Juice + liquid meal test at baseline

Sweetened placebo beverage + liquid meal test at baseline

PLACEBO COMPARATOR

Participants will consume placebo beverage + liquid meal test at baseline. They will then consume watermelon juice daily for 4 weeks. Watermelon juice + liquid meal test will be consumed at endpoint.

Other: Sweetened placebo beverage +liquid meal test at baseline

Interventions

Sweetened placebo beverage +liquid meal test at baseline OTHER

The placebo beverage made of water and sugar will match the sugar content provided in 355 ml of WMJ (approximately 10-20 g). The liquid meal test will be in the form of the Boost nutritional drink (8 fl.oz., vanilla flavor), which is commercially available.

Sweetened placebo beverage + liquid meal test at baseline

Watermelon Juice + liquid meal test at baseline OTHER

WMJ will be purchased from a commercially available brand. The liquid meal test will be in the form of the Boost nutritional drink (8 fl.oz., vanilla flavor), which is commercially available.

Watermelon Juice + liquid meal test at baseline

Eligibility Criteria

• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• Female
• Generally healthy
• Postmenopausal
• BMI 25-40 kg/m2
• Systolic blood pressure 120-139 mmHg and/or diastolic 80-89 mmHg
• Fitzpatrick Skin type II-IV
• Consume a typical Western diet (low in polyphenol/lycopene-rich foods and fiber)
• Willing to maintain habitual dietary and exercise patterns for the study duration
• Willing to maintain normal skin care products and pattern for the duration of the study
• Willing to come to Baseline Visit B and Week 4 study visits without any makeup and skin products on
• Subjects must read and sign the Institutional Review Board-approved written informed consent prior to the initiation of any study specific procedures or enrollment. A subject will be excluded for any condition that might compromise the ability to give truly informed consent.

You may not qualify if:

• Non-English speaker
• Vegetarian/vegan
• Known watermelon allergy
• Skin-related prescription medication, supplements, or non-prescription cosmeceutical agents
• Initiation of topical or oral prescription steroids and/or anti-inflammatory medications within 30 days prior to study enrollment
• Excessive exposure to either natural or artificial sunlight. Exposure to sunlight will be evaluated using Fitzpatrick Skin Type test score. Individuals receiving scores higher than the upper cutoff of the proposed range for the specific skin type will be excluded
• Screening laboratory values outside of the normal range that is considered clinically significant for study participation by the investigator
• Documented chronic disease, including diabetes, renal or liver diseases, metabolic syndrome, active cancer, MI or stroke, history of gastric bypass or GI disease (e.g., Crohn's disease, IBD, diverticulosis, diverticulitis, etc.)
• Taking medications or supplements known to affect metabolism or gut microbiota composition (antibiotics within the past 3 months, probiotics, fiber, etc.), unless willing to stop for the study duration
• Taking exogenous hormones (e.g., hormone replacement therapy)
• Recent weight fluctuations (\>10% in the last 6 months)
• Smoker or living with a smoker
• Use of \>20 g of alcohol per day
• Unable or unwilling to comply with the study protocol (including unwillingness to avoid watermelon and other lycopene-rich foods for the whole duration of the study)
• Unable to provide consent

Sponsors & Collaborators

• National Watermelon Promotion Board: collaborator
• University of California, Los Angeles: lead

Study Sites (1)

UCLA Center for Human Nutrition

Los Angeles, California, 90095, United States

Location

Study Officials

• Zhaoping Li, MD, PhD

  University of California, Los Angeles

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Tatiana Diacova, PhD, MS, RDN

CONTACT

3102068292; tdiacova@mednet.ucla.edu

Study Design

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

Study Record Dates

• First Submitted: May 28, 2025
• First Posted: June 5, 2025
• Study Start: April 1, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): September 1, 2027
• Last Updated: March 12, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)