Food scientists at Florida State University found that consumption of six grams of L-citrulline from watermelon extract for six weeks normalized the blood pressure of all nine adults in the study who previously had elevated blood pressure, The News reported.
Dr. Arturo Figueroa, lead researcher of the new study, claimed that they are the first to document improved aortic hemodynamics in pre-hypertensive but otherwise healthy middle-aged men and women receiving therapeutic doses of watermelon.
These findings suggest that this 'functional food' has a vasodilatory effect, and one that may prevent prehypertension from progressing to full-blown hypertension, added Figueroa.
The large watermelon fruit is the richest edible source of the amino acid L-citrulline, which regulates healthy blood pressure. L-citrulline is converted to another amino acid, L-arginine, once in the body.
However, taking L-arginine as a dietary supplement can cause nausea, gastrointestinal problems and diarrhea, especially among adults who already suffer from raised blood pressure.
Figueroa suggested that people with increased blood pressure and arterial stiffness - especially those who are older and those with chronic diseases such as type 2 diabetes - would benefit from L-citrulline in either the synthetic or natural (watermelon) form.
The study has just been published in the American Journal of Hypertension.