Watermelon might be doing more than cooling people down in hot weather.

Research highlighted by Wild Hive says people who eat watermelon tend to have higher-quality diets, and one clinical trial found watermelon juice may help support blood vessel function and heart health.

Studies published in Nutrients found regular watermelon consumers generally took in more dietary fiber, magnesium, potassium, vitamin C, vitamin A, lycopene and other carotenoids. They also consumed lower amounts of added sugars and saturated fat.

One of the studies looked at data from the National Health and Nutrition Examination Survey, comparing watermelon eaters and non-consumers across the United States. It found both children and adults who consumed watermelon generally had healthier overall diets. The study was originally published in Nutrients in 2022.

The findings come as many Americans still fall short of fruit intake targets. The Dietary Guidelines for Americans recommend between 1.5 and 2.5 cups of fruit a day, but most adults and children consume only about half that amount.

A separate clinical trial from Louisiana State University looked at watermelon juice and blood vessel function during periods of elevated blood sugar. The randomized, double-blind, placebo-controlled crossover study involved 18 healthy young adults who consumed watermelon juice daily for two weeks.

Researchers focused on L-citrulline and L-arginine, two naturally occurring compounds in watermelon involved in nitric oxide production. Nitric oxide helps blood vessels relax and expand, which is part of healthy circulation and cardiovascular function.

The study found evidence that watermelon juice supplementation helped maintain vascular function during hyperglycemia and influenced heart rate variability.

“We acknowledge that while the sample size was small (18 healthy young men and women) and more research is needed, this study adds to the current body of evidence supporting regular intake of watermelon for cardio-metabolic health. In addition to L-citrulline and L-arginine, watermelon is a rich source of antioxidants, vitamin C and lycopene, all of which can help reduce oxidative stress and play a role in heart disease prevention,” said Dr. Jack Losso, Ph.D., professor at Louisiana State University’s School of Nutrition and Food Sciences.

Wild Hive said later reviews and meta-analyses have continued to examine watermelon’s role in vascular and metabolic health. Researchers have reported that watermelon consumption and L-citrulline supplementation may improve measures linked to blood vessel flexibility and circulation, including pulse wave velocity and endothelial function.

Scientists are particularly interested in watermelon because it is one of the richest natural food sources of L-citrulline. Reviews have also pointed to its potential role in supporting nitric oxide production, healthy blood flow and cardiovascular function, though experts say larger long-term studies are still needed.

Watermelon also contains lycopene, which Wild Hive described as a powerful antioxidant associated with reduced oxidative stress and possible heart health benefits. Red watermelon varieties tend to contain especially high levels of lycopene.

The fruit is also low in calories and high in water. A 2-cup serving contains 80 calories, 25 percent of the daily value for vitamin C, and 8 percent of the daily value for vitamin B6. Watermelon is about 92 percent water.

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