Introduction for Watermelon Benefits are Related to L-citrulline, and Citrulline malate
Watermelon benefits are related to it’s L-citrulline, and citrulline malate content. L-citrulline is an amino acid produced in the body or taken into the body by the diet. It can be found in everyday foods such as watermelons. After consuming watermelon, the kidneys and vascular endothelium (smooth muscle lining of blood vessels), convert the citrulline into arginine. Arginine levels in the body then increase, which produce nitric oxide to be used for dilation of blood vessels. Citrulline is found in yellow watermelons in a higher concentration than red watermelon. L-citrulline has some evidence in research for benefit in the treatment of high-blood pressure, erectile disfunction, in improvement of exercise performance, as well as faster exercise recovery.
Watermelon and High Blood Pressure:
The watermelon benefits of L-citrulline was examined by Figueroa A, et al (1). The authors found that watermelon extracts may prevent the progression of prehypertension to hypertension. Nine participants (4 men and 5 postmenopausal women, ages 51-57) were randomly divided into two groups. The treatment group received watermelon powder supplementation, containing 1.35 g of L-citrulline and 0.65 g of L-arginine, twice every day for six weeks after which a 4-week washout period was observed. The control subjects received a similar looking placebo. At the end of study period, there was improved arterial function and consequently lowered aortic blood pressure in all 9 of their prehypertensive subjects. Compared to the control group, those who consumed watermelon supplementation had their blood pressure in the arm reduced by 8 mm of Hg, aortic systolic blood pressure reduced by 7 mm of Hg, and augmentation index (a surrogate measure of arterial stiffness) reduced by about 6%. These findings suggested that L-citrulline and L-arginine dilates blood vessels, which consequently may prevent prehypertension from progressing to full-blown hypertension.
Watermelon, L-Citrulline and Sexual Dysfunction:
L-citrulline is a natural substance in watermelon which has shown to improve erection in men in a study. Cormio L et al (2) tested oral L-citrulline supplementation in improving erection hardness in patients with mild erectile dysfunction (ED). Twenty-four men with an average age of 56.5 years old with mild ED (erection hardness score [EHS] of 3) received a placebo for 1 month, followed by L-citrulline, at 1.5 g/day for another month. The equivalent amount in red watermelon would be about 3 to 4 large wedges per day or 1 wedge of yellow watermelon due to higher L-citrulline content. At the end of the study, improvement in the EHS from 3 (mild ED) to 4 (normal erectile function) occurred in 2 (8.3%) of the men when taking placebo during the first half of the study. But when the subjects were switched to L-citrulline, 12 (50%) of the men reported achieving an EHS of 4. An EHS of 3 is considered “hard enough for penetration but not completely hard,” while an EHS 4 is “completely hard and fully rigid.” At the same time, the mean number of intercourses per month increased from 1.37 at baseline to 1.53 at the end of the placebo phase (about 12% greater frequency) and 2.3 at the end of the treatment phase (about a 68% increase) for L-citrulline. L-citrulline increased successful intercourse by 56% more than placebo. L-citrulline may be successfully used among men with mild ED.
Citrulline malate and Exercise Performance:
Watermelon Benefits are Related to L-citrulline, and Citrulline malate. Citrulline is a non-essential amino acid which has previously been found to increase arginine in the body which converts to nitric oxide leading to dilation of blood vessels. Pérez-Guisado J, et al (3) examined the effects of citrulline malate on the performance of flat barbell bench presses in a randomized, double-blind, 2-period crossover study. Forty-one men each performed 2 consecutive training sessions of 16 sets of chest training. Each subject was given citrulline malate and a similar looking placebo, but randomly on either the first or second training session. Results show that when the subjects were using the citrulline malate they were able to perform more repetitions in the later sets (52.92% more repetitions), and also had significantly less reported muscle soreness—a decrease of 40% in muscle soreness at 24 hours and 48 hours after the training session. The only reported side effect was stomach discomfort experience by 14.63% of men. This research shows that citrulline malate may be beneficial to men in intensive high level training.
Summery for Watermelon Benefits are Related to L-citrulline, and Citrulline malate
- A study by Figueroa A et al included 9 pre-hypertensive subjects who took watermelon powder containing 1.35 g of L-citrulline and 0.65 g of L-arginine, twice every day for six weeks, lowered aortic blood pressure by 7 mm Hg and arm bp by 8 mm of Hg.
- Men who took L-citrulline in a study by Cormio L et al, at a dose of 1.5 g/day (equivalent to 3 to 4 large wedges of red watermelon per day or 1 wedge of yellow watermelon per day) for 1 month resulted in a completely hard and fully rigid erection in 50% of the treatment group vs. 8.3 % with placebo. Also the number of intercourses per month increased from 1.37 at baseline to 2.3 at the end of the treatment phase vs. 1.53 with placebo.
- Pérez-Guisado J et al showed in a trial that 8 grams of citrulline malate given to male subjects resulted in a performance of 52.92% more repetitions in later sets and a decrease of 40% in muscle soreness at 24 hours and 48 hours after the training session compared to placebo. Stomach discomfort was the only adverse effect reported in 14.63%
References for Watermelon Benefits, L-citrulline, and Citrulline malate
1.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. Am J Hypertens. 2011 Jan;24(1):40-4. http://www.nature.com/ajh/journal/v24/n1/fig_tab/ajh2010142t1.html#figure-title
2.Cormio L, De Siati M, Lorusso F, Selvaggio O, Mirabella L, Sanguedolce F, Carrieri G. Oral citrulline supplementation improves erection hardness in men with mild erectile dysfunction. Urology 2011 Jan;77(1):119-22. http://www.ncbi.nlm.nih.gov/pubmed/21195829
3.Pérez-Guisado J, Jakeman PM. Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. J Strength Cond Res. 2010 May;24(5):1215-22. http://www.ncbi.nlm.nih.gov/pubmed/20386132