The flesh and rind of watermelons contain citrulline, which reacts with the body's enzymes when consumed in large quantities. The compound is changed into arginine, an amino acid that benefits the heart and the circulatory and immune systems. Just like the popular Viagra and other drugs meant to treat erectile dysfunction (ED), it also helps relax and dilate blood vessels.
Researchers are now working on breeding watermelons with higher concentrations of citrulline in the flesh of the fruit. Nearly 60 percent of this phyto-nutrient is found in watermelon rind than the flesh. Though found in all colors of watermelon, it has the highest concentration in the yellow fleshed types.
However, a person would need to eat about six cups of watermelon to get enough citrulline to boost the body's arginine level and have the desired effect.
The organic compound citrulline is an alpha-amino acid. Its name is derived from citrullus, the Latin word for watermelon, from which it was first isolated in 1930. Citrulline in the form of citrulline malate is sold as a performance-enhancing athletic dietary supplement which is said to reduce muscle fatigue.
