The watermelon is a deliciously sweet and refreshing fruit that is packed with nutrients. Regularly eating watermelon is an excellent way to replenish and hydrate the body - and now there's more. Evidence from a pilot study suggests that watermelon can be an effective natural weapon that lowers blood pressure and is linked to protecting against prehypertension, a precursor to cardiovascular disease.

Researchers reported that amino acids found in the fruit improved the performance of arteries and lowered blood pressure in each of nine subjects with prehypertension.

Study Details

In the first investigation of its kind in humans, scientists found that when six grams of the amino acid L-citrulline / L-arginine from watermelon extract was administered daily for six weeks, there was improved arterial function and consequently lowered aortic blood pressure in all nine of their prehypertensive subjects.

"We are the first to document improved aortic hemodynamics in prehypertensive but otherwise healthy middle-aged men and women receiving therapeutic doses of watermelon," one of the authors said.

"These findings suggest that this 'functional food' has a vasodilatory effect, and one that may prevent prehypertension from progressing to full-blown hypertension, a major risk factor for heart attacks and strokes.

"Given the encouraging evidence generated by this preliminary study, we hope to continue the research and include a much larger group of participants in the next round," he said.

Why watermelon?

The amino acid L-arginine is essential to maintaining healthy blood pressure, and as one of the study authors explained:

"Watermelon is the richest edible natural source of L-citrulline, which is closely related to L-arginine, the amino acid required for the formation of nitric oxide essential to the regulation of vascular tone and healthy blood pressure."

Once in the body, the L-citrulline is converted into L-arginine. Simply consuming L-arginine as a dietary supplement isn't an option for many hypertensive adults, because it can cause nausea, gastrointestinal tract discomfort, and diarrhea.

In contrast, the study revealed no adverse effects from subjects eating watermelon, which is rich in a compound that is converted to L-arginine once inside the body. And, in addition to the benefits of citrulline, watermelon provides abundant amounts of vitamins A, B6, C, and is one of the richest sources of lycopene, a powerful antioxidant.

Research Paper Details

Figueroa A, Sanchez-Gonzalez MA, Perkins-Veazie PM, Arjmandi BH. Effects of watermelon Supplementation on Aortic blood pressure and Wave Reflection in Individuals With Prehypertension: A Pilot Study. American Journal of hypertension, 2010.