NCT07006636 · University of California, Los Angeles
Effect of Watermelon on Cardiometabolic Health
What this study is about
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.
View original scientific description
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).
Interventions
OTHER
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.
OTHER
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 measures
Postprandial blood pressure
Time frame: Baseline and Week 4
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.
Postprandial heart rate
Time frame: Baseline and 4 weeks.
Will be measured in beats per minute.
Postprandial pulse wave velocity
Time frame: Baseline and 4 weeks.
Will be measured in meters/second.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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
Where
- Los Angeles, California
Collaborators
National Watermelon Promotion Board
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 31, 2026 · Source of record for eligibility and locations