Researchers reported that a combination of watermelon and pomegranate juice enriched with citrulline and ellagitannins produced beneficial effects regarding metabolism and performance, according to data published in the Journal of Agricultural and Food Chemistry.
“[A] unique dose of 200 mL of watermelon juice enrichment with citrulline (3.3 g per 200 mL) showed an ergogenic effect, which was improved with ellagitannins supplementation (22.0 mg per 200 mL) from pomegranate fruit concentrate,” wrote researchers from the Cartagena-based Institute of Plant Biotechnology and the Hospital General Universitario Santa Lucı́a, and the Catholic University of Murcia.
“These functional juices have shown a benefit in athletes, increasing the average peak force around 3% and reducing around 5 times the decrease in peak torque. Moreover, the subjective [rating of perceived exertion (RPE)] and muscle soreness were lower than with placebo in enrichment juices.
“At the same time, levels of some biochemical markers associated with muscle damage such as [lactate dehydrogenase], myoglobin, uric acid, and urea were maintained. These kinds of beverages could be useful also in workers that need an extra physical effort. The promising results should take into account the synergic effect of the natural fruit drink matrix.”
The beverages for the study were provided by AMC Innova Juice and Drinks, S.L., and the study was supported financially by the Spanish National Centre for the Development of Industrial Technology.
The researchers recruited 19 young men aged between 18 and 30 to participate in their double-blind, randomized crossover study. The men were randomly assigned to consume a single dose (200 mL) one of four test beverages: Watermelon juice; watermelon juice enriched with citrulline; watermelon and pomegranate juice enriched with citrulline and ellagitannins; and placebo. A one week “washout” period followed each intervention before the men crossed over to a different group.
Results from physically intensive squat exercise indicated that the watermelon/pomegranate combination significantly reduced muscle soreness compared to placebo, with no muscle soreness at all reported after 48 hours.
Data from the placebo intervention indicated that myoglobin and lactate dehydrogenase (LDH), markers of muscle of muscle damage, were higher than when they drank the watermelon/pomegranate combination.
Effects on the mitochondria
Commenting on the potential mechanism(s) of action, the researchers noted that about 80% of citrulline is converted to arginine by the kidneys, which is subsequently converted to nitric oxide. NO is a potent vasodilator that has been reported to boost blood flow and mitochondrial respiration, “particularly during exercise and increases muscle contractility, muscle repair, muscle blood flow, glucose uptake, and resistance exercise performance”.
In addition, ellagitannins from pomegranate may be converted to urolithin A by bacteria in the gut, which may also improve mitochondrial respiratory capacity and enhance muscle strength
“Given the potential ergogenic mechanisms of citrulline involving oxygen delivery and mitochondrial efficiency, it is possible that citrulline and ellagitannins supplementation preferentially enhances aerobic exercise capacity compared to higher intensity anaerobic activities,” i“These mechanisms activated aerobic glycolysis, and therefore the reaction of pyruvate to lactate is reduced, thereby decreasing LDH compared to the placebo.”
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, Article ASAP, doi: 10.1021/acs.jafc.7b00586
“Consumption of Watermelon Juice Enriched in l-Citrulline and Pomegranate Ellagitannins Enhanced Metabolism during Physical Exercise”
Authors: A. Martinez-Sanchez et al.