Compound in Watermelon Lowers Blood Pressure

TALLAHASSEE, Fla.—Will watermelon be the next on-trend flavor featured in heart-healthy foods or beverages? New research published in the American Journal of Hypertension reveals watermelon could significantly reduce blood pressure in overweight individuals while under the stress of cold weather conditions.

Researchers at Florida State University conducted the study to assess the effect of L-citrulline-rich watermelon supplementation on aortic hemodynamic responses to CPT in hypertensive adults. They studied 13 middle-aged obese men and women with high blood pressure during a 12-week study. To simulate cold weather conditions, one hand of the subject was dipped into 39° water, while Figueroa’s team took his or her blood pressure and other vital measurements.

The group was divided into two. For the first six weeks, one group was given 4 grams of the amino acid L-citrulline and 2 grams of L-arginine per day, both from watermelon extract. The other group was given a placebo for six weeks. Then, they switched for the next six weeks. Participants also had to refrain from taking any medication for blood pressure or making any significant changes in their lifestyle, particularly related to diet and exercise, during the study. 

The study's results indicated that consuming watermelon had a positive impact on aortic blood pressure and other vascular parameters. Notably, study participants showed improvements in blood pressure and cardiac stress while at rest and while they were exposed to the cold water.

“That means less overload to the heart, so the heart is going to work easily during a stressful situation, such as cold exposure," said lead author Arturo Figueroa, FSU associate professor.

Figueroa isn't the first to discover watermelon's heart health properties. Previous research from Purdue University and the University of Kentucky shows eating watermelon can significantly boost heart health while also helping subjects lose weight. The findings suggest the compound citrulline, found naturally in watermelon, plays a key role in heart health.