Recruiting

Watermelon Juice

Sponsor:

UCLA

Code:

NCT07006636

Conditions

Cardiometabolic Health Indicators

Whole-body Antioxidant Capacity

Eligibility Criteria

Sex: Female

Age: 0+

Healthy Volunteers: Accepted

Interventions

Watermelon Juice + liquid meal test at baseline

Sweetened placebo beverage +liquid meal test at baseline

Study Details

Brief summary:

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

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. 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.

This will be determined immediately after consuming the juice (to evaluate the effects the juice has on health right away), as well as after 4 weeks of daily juice consumption (to evaluate the effects the juice has on health when consumed consistently over time).

Conditions

Cardiometabolic Health Indicators

Whole-body Antioxidant Capacity

Study ID

NCT07006636

Start date

Apr 1, 2026

Status verified date

Jul, 2026

Completion date

Sep 1, 2027

Anticipated

Primary completion date

Sep 1, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: Female

Age: 0+

Healthy Volunteers: Accepted

Inclusion Criteria:

  • 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.

Exclusion Criteria:

  • 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

Study Design

Enrollment

22 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Prevention

Interventions and Outcome Measures

Arms

experimental: Watermelon Juice + liquid meal test at baseline

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.

placebo comparator: Sweetened placebo beverage + liquid meal test at baseline

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.

Interventions

Watermelon Juice + liquid meal test at baseline

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.

Sweetened placebo beverage +liquid meal test at baseline

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.

Primary outcome measure

  • Postprandial blood pressure [ Time Frame: Baseline and Week 4 ]
  • Postprandial heart rate [ Time Frame: Baseline and 4 weeks. ]
  • Postprandial pulse wave velocity [ Time Frame: Baseline and 4 weeks. ]

Central Contacts and Locations

Central contacts

Tatiana Diacova, PhD, MS, RDN

3102068292tdiacova@mednet.ucla.edu

Locations

UCLA Center for Human Nutrition

Recruiting

Los Angeles, California, United States, 90095

Contacts

Tatiana Diacova, PhD, MS, RD

310-206-8292tdiacova@mednet.ucla.edu

Principal Investigator:

Zhaoping Li, MD, PhD

More Information

Sponsor

University of California, Los Angeles

Last update posted

Jul 31, 2026

Last verified

Jul, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of California, Los Angeles on 2026-07-31.