Cardiometabolic Health IndicatorsNCT07006636
Effect of Watermelon on Cardiometabolic Health
A study testing Watermelon Juice + liquid meal test at baseline in people with Cardiometabolic Health Indicators and Whole-body Antioxidant Capacity, run by University of California, Los Angeles at 1 site in United States.
Trial 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. Read more about this study
- Who is it for?
- Any age, women onlyHealthy volunteers can take part
- Conditions the study is for
- Cardiometabolic Health Indicators, Whole-body Antioxidant Capacity
- What is being tested?
- Watermelon Juice + liquid meal test at baseline
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 22 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Apr 2026to 1 Sep 2027
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- Women only
- Healthy volunteers accepted
- Child, Adult, Older adult
Who may be able to join
- 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
Show all 11Show fewer
- 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.
Who cannot join
- 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
Show all 15Show fewer
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
UCLA Center for Human Nutrition
Los Angeles, California, 90095
Tatiana Diacova, PhD, MS, RD, 310-206-8292, tdiacova@mednet.ucla.edu
Zhaoping Li, MD, PhD
About this study
Official title: Effect of Watermelon Consumption on Cardiometabolic Health and Whole-Body Antioxidant Capacity
The purpose of this study is to determine whether consumption of 355 ml of watermelon juice will:
- improve cardiovascular and overall metabolic health markers like blood pressure, heart rate, stiffness/flexibility of arteries (blood vessels), blood sugar, cholesterol), and gut hormones
- 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).
Read the detailed description
Both hypertension and oxidative stress are among the major risk factors for cardiovascular disease (CVD). While CVD is a multifactorial disease, it has been established that diet plays an integral role in its pathogenesis. In fact, it has been previously demonstrated that almond and pomegranate consumption may be able to strengthen the body's antioxidant defense mechanisms and aid in improving several cardiometabolic health biomarkers. Watermelon, being rich in fiber, vitamins, minerals, and bioactive compounds (e.g., L-citrulline, lycopene, beta-carotene) may also have similar health effects. Notably, studies involving both mice and humans have demonstrated the potential of watermelon consumption to prevent CVD by lowering blood pressure and low-density lipoprotein cholesterol (LDL-C).
Emerging evidence suggests that postprandial biomarker levels may serve as better and earlier predictors of CVD development than their fasting levels. While watermelon is often consumed with or after a meal, no studies have evaluated the effect of watermelon on postprandial biomarker responses after a meal challenge. In addition, despite the high bioactive content of watermelon, its effects on whole-body antioxidant capacity have not been explored yet.
Therefore, in the present study it is proposed to evaluate the acute (postprandial) and chronic (4 weeks of daily consumption) effects of 355 ml of watermelon juice (WMJ) on: 1) cardiometabolic risk factors including blood pressure, heart rate, pulse wave velocity (PWV), blood glucose and lipids/lipoproteins, nitric oxide (NO), insulin/C-peptide, and GLP-1; and 2) whole-body antioxidant capacity by evaluating skin resistance to UV irritation, as well as blood and urine malondialdehyde (MDA) levels. A two-phase intervention study (2-week standardization phase and a 4-week intervention phase) involving 20 generally healthy non-vegetarian/vegan postmenopausal women with slightly elevated blood pressure, overweight/obese BMI, and Fitzpatrick's skin types II-IV will be performed. Investigating the effects of WMJ consumption on cardiometabolic risk factors and skin antioxidant defense/systemic oxidative status will uncover valuable new insights into whether bioactive compounds in watermelon can affect cardiometabolic risk and contribute to the total body antioxidant capacity.
- Being tested
- Watermelon Juice + liquid meal test at baseline, Sweetened placebo beverage +liquid meal test at baseline
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Watermelon Juice + liquid meal test at baselineOther
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 baselineOther
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.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: Other: Sweetened placebo beverage +liquid meal test at baseline |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: Baseline and Week 4
Postprandial heart rate
Will be measured in beats per minute.
Measured: Baseline and 4 weeks.
Postprandial pulse wave velocity
Will be measured in meters/second.
Measured: Baseline and 4 weeks.
Secondary outcomes (6)
Postprandial nitric oxide (NO)
Will be measured in µmol/L
Measured: Baseline and 4 weeks.
Postprandial glucose
Dysregulation of postprandial glucose and lipid responses has been implicated in the development of metabolic diseases. A previous study showed that watermelon juice consumption acutely stabilized postprandial glucose and insulin levels compared to matched sugar water in healthy subjects. Here, we will evaluate both acute and chronic effects of watermelon juice on postprandial circulating biomarker responses.
Measured: Baseline and 4 weeks.
Postprandial blood lipids/lipoproteins (LDL cholesterol, HDL cholesterol, total cholesterol, triglycerides).
All will be measured in mg/dL.
Measured: Baseline and 4 weeks.
Postprandial insulin
Will be measured in international units.
Measured: Baseline and 4 weeks.
Postprandial C-peptide
Will be measured in nmol/L
Measured: Baseline and 4 weeks.
Postprandial GLP-1
Will be measured in pmol/L
Measured: Baseline and week 4
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted5 Jun 2025
- Study start1 Apr 2026
- Primary completion1 Sep 2027 (estimated)
- Study completion1 Sep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cardiometabolic Health IndicatorsStudies of the same condition, open and under way.
- More trials run by University of California, Los AngelesThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 22 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, Los Angeles
- Sponsor type
- University, hospital or other
- Collaborators
- National Watermelon Promotion Board
- Responsible party
- Principal investigator, Zhaoping Li, University of California, Los Angeles
- Investigators
- Zhaoping Li, MD, PhD, Principal investigator, University of California, Los Angeles
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07006636
- Sponsor's protocol ID
- IRB-25-1126
- Status last verified
- Jul 2026
- First submitted
- 28 May 2025
- Last updated
- 31 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Data analysis will be performed in-house.