Watermelon juice and blood vessel function in postmenopausal women
What it found
Drinking watermelon juice for four weeks raised lycopene levels but did not change blood vessel function in healthy postmenopausal women.
Fasting blood sugar rose slightly, though the authors say the change was too small to matter clinically.
What they found
Studies in people
Lycopene levels in blood
Drinking the watermelon juice raised lycopene levels in the blood compared to the placebo drink. Lycopene is a plant compound found heavily in watermelon.
Blood vessel measures unchanged
The juice did not change any measure of blood vessel function. Arterial stiffness, blood pressure over 24 hours, and how well arteries widened all stayed about the same as with the placebo.
Amino acids in blood
Even though the juice provided extra arginine and citrulline, fasting blood levels of these amino acids did not rise. The daily dose may have been too low to change blood levels in this group.
Fasting blood sugar
Fasting blood sugar was slightly higher after the juice period than after the placebo. The authors note the levels stayed well below the point considered impaired fasting glucose.
Body weight and fat
Drinking the juice did not noticeably change body mass index or estimated body fat percentage over the four weeks.
What the authors conclude
- They conclude that four weeks of pasteurized watermelon juice raised blood lycopene but did not improve blood vessel function in healthy postmenopausal women.
- They suggest the juice might work differently in people who already have high blood pressure or other heart risks, based on earlier studies.
- They call for more research into how processing methods affect the active compounds in watermelon.
How it was done
Heart disease risk rises after menopause, and stiffening blood vessels are an early warning sign. The authors wanted to see if drinking watermelon juice could support blood vessel health before problems start, since earlier work used extracts that are hard to buy in stores.
Twenty-one healthy women aged 55 to 70 who had been through menopause took part. Each woman drank two 360 mL servings of 100% watermelon juice daily for four weeks, then a matching placebo drink for four weeks, with a two-week break between them. Researchers measured blood vessel stiffness, blood pressure, and blood markers before and after each period.
What it can’t tell you
- This trial only included healthy, non-obese women who had been through menopause, so the results may not apply to men, younger adults, or people with existing heart conditions.
- Seventeen of the 21 women finished the study, which is a small group for detecting subtle changes in some blood vessel measurements.
- The trial lasted four weeks per drink, so it cannot show what happens when people drink watermelon juice over many months or years.
Who paid
- Funding
- Funded by NIA NIH HHS; NIDDK NIH HHS (from the PubMed record).
- Conflicts
- Declaration of competing interest The authors have no conflicts of interest to disclose.
- Authors work at
- University of Alabama, USA; University of Alabama at Birmingham, USA
The paper
- Title
- Daily 100% watermelon juice consumption and vascular function among postmenopausal women: A randomized controlled trial
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Ellis AC, Mehta T, Nagabooshanam VA, Dudenbostel T, Locher JL, Crowe-White KM (2021). Daily 100% watermelon juice consumption and vascular function among postmenopausal women: A randomized controlled trial. Nutrition, metabolism, and cardiovascular diseases. doi:10.1016/j.numecd.2021.06.022Free full textPubMed 34344546DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error