I consume watermelon on a regular basis. This fruit has been used for myself and the athletes that I train, during and after competitions have urged them to incorporate watermelon consumption as part of their regular diet. I had no idea how much good was coming from eating the fruit. Not only is watermelon an extremely tasty whole food, but it has a positive effect upon the functions of the human body.
Watermelon Consumption Increases Plasma Arginine Concentrations in Adults was the title of research article that I selected. The 19 week study including 12 males and 11 females between the ages of 36-69 was approved by the committee on human research of the Johns Hopkins School of Public Health and Hygiene in Baltimore, MD. The purpose of the study was to determine the level of effectiveness of consuming specific amounts of watermelon over the three week period and measure the results. Watermelon contains a large amount of citrulline which the body converts to arginine. The amino acid arginine is required to produce proteins and other molecules, including nitric oxide, proline and creatine. Nitric oxide (NO), is responsible for regulation of vascular tone and aids in the prevention of pathogens and tumor cells as an important part in boosting immunity. Proline is essential part of collagen and is critical to joint function and wound healing. Creatine is a major energy storing substance for and critical to the function of skeletal muscle and neuronal cells. Taking an oral form of arginine has been used to aid the bodily functions, but 40% is catabolized by the intestinal tissues and another 10 to 15% of the amino acid is processed by the liver. Whereas citrulline by passes the liver completely with minimal intestinal absorption, therefore leaving the body free to access the full amount of converted arginine.
The subjects were given either 3 cups (780 grams) or 6 cups (1560 grams) of watermelon juice. There was no control group for this experiment. There were several periods prior, during and upon completion of the watermelon juice consumption that fasting measurements taken revealed that plasma levels of arginine and ornithine and stable amounts of plasma citrulline were present. The rates were up to 22% greater than prior to ingestion of the watermelon juice.
I do believe that the experiment has validity. Though the group was not large a one, the data provided significant proof that watermelon ingestion does increase the levels of arginine and other amino acids that are essential to maintaining and achieving good health.
Collins, J K., Wu, G., Perkins-Veazie, P., Spears, K., Claypool, P. L. et al. (Mar, 2007) Watermelon consumption increases plasma arginine concentrations in adults. Nutrition; Kidlington Vol. 23, Iss. 3. Doi_10.1016_j.nut.2007.01