Recent study results suggest that watermelon may help to lower blood pressure in people who are obese. Arturo Figueroa, an associate professor in nutrition, food, and exercise sciences at Florida State University, and colleagues carried out a 12-week study focused on 13 middle-aged, obese men and women who also had high blood pressure. The group was divided into 2, and for the first 6-weeks, one group was given a watermelon extract containing the amino acids 4 g L-citrulline and 2 g L-arginine each day. The other group was given a placebo for 6-weeks. After 6-weeks, the groups switched over for the second 6-weeks. During the study participants had to refrain from taking any anti-hypertensive medication or making any significant changes in their lifestyle. Results showed that consuming the amino acids from the watermelon reduced aortic blood pressure and myocardial oxygen demand both at rest and while under stress.

From: http://www.worldhealth.net/news/watermelon-extract-lowers-blood-pressure/