Research reveals watermelon offers cardiovascular and metabolic benefits well beyond summer refreshment

Watermelon has long been regarded as a quintessential summer fruit, but emerging research indicates that this 92%-water staple may offer significant cardiovascular and metabolic benefits that extend well beyond simple refreshment.

Two studies point to broader health gains

Two studies — one reviewing National Health and Nutrition Examination Survey (NHANES) data and another drawing on clinical trials from Louisiana State University — found that individuals who consume watermelon regularly tend to have better overall dietary patterns and may also show improvements in cardiovascular function.

Better diets among regular watermelon consumers

A 2022 analysis published in the journal Nutrients examined NHANES data, comparing the dietary habits of regular watermelon consumers with those who did not eat the fruit.

The findings revealed that both children and adults who ate watermelon on a regular basis tended to consume notably higher levels of dietary fibre, magnesium, potassium, vitamin C, vitamin A, lycopene, and carotenoids.

At the same time, those same groups showed lower intakes of added sugars and saturated fat — a dietary profile that many Americans find difficult to maintain.

This is particularly relevant given that the Dietary Guidelines for Americans recommend 1.5 to 2.5 cups of fruit per day, yet most children and adults consume closer to half that amount.

With its high water content and low-calorie profile — approximately 80 calories per two-cup serving — watermelon represents a practical and accessible way to increase daily fruit intake.

Cardiovascular benefits identified in a clinical trial

A separate study conducted at Louisiana State University examined the cardiovascular effects of watermelon more directly. The randomised, double-blind, placebo-controlled trial involved 18 healthy volunteers and found that watermelon consumption helped maintain healthy vascular function during periods of elevated blood sugar, whilst also positively affecting heart rate variability.

The role of L-citrulline and L-arginine

These benefits are attributed to two naturally occurring compounds found in watermelon: L-citrulline and L-arginine. Both stimulate the release of nitric oxide in the body, a substance that facilitates the relaxation and expansion of blood vessels.

According to Dr Jack Losso, Professor at the Louisiana State University School of Nutrition and Food Sciences, watermelons are among the most abundant natural sources of L-citrulline available.