Can Watermelon Enhance Physical Health?

Background

Watermelon (Citrullus lanatus L.) originates from arid regions of southern Africa, and its fruit contains a large amount of the amino acid citrulline, an efficient free radical scavenger. The elevated content of l-citrulline allows wild watermelon to resist drought-mediated oxidative stress in harsh environments.

Until recently, l-citrulline attracted little interest among the nutrition community, almost certainly because it is a non-protein amino acid and was viewed solely as a metabolic intermediary in the urea cycle.

L-citrulline is mostly absent from natural foods, watermelon being a notable exception. These antioxidant properties, together with the ability to generate nitric oxide (NO), make citrulline an excellent candidate for the treatment of pathological situations characterized by oxidative stress

For example, heart failure, atherosclerosis, sickle cell disease, and sexual stamina and erectile functions. A dietary supplement rich in l-citrulline also helps in smooth muscle relaxation thus lowering blood pressure.

Other benefits associated with l-citrulline intake include improving athletic performance due to nitric oxide production and increasing glucose transport in skeletal muscle. L-Citrulline was shown to increase levels of arginine and ornithine (which are important for muscle growth) and influence levels of growth hormone. For example, in aged rats, 1 week of feeding an l-citrulline-enriched diet induced an increase in absolute muscle protein synthesis rate together with an increase in protein.

Recent studies indicate that watermelon supplementation as a nutritional might also enhance core skeletal muscle contractility and improve the speed and power of muscle contraction.  L-Citrulline also accelerates lactic acid removal, allowing better physical performance, that is, more intense training and faster recovery after each workout.

Moreover, several investigations suggest that nitric oxide supplementation may improve aspects of cognitive performance both at rest and during exercise. 

When watermelons were analyzed to determine the citrulline content among varieties, types, flesh colors, and tissues, citrulline content weight was similar between seeded and seedless types.  Red flesh watermelons had slightly less citrulline than the yellow or orange flesh watermelons.  The rind contained more citrulline than flesh.  Spatial determinations have found the highest content of citrulline in the peel, then the rind followed by the center fleshy portions.   

Increased watermelon consumption appears to represent a promising new approach for enhancing aspects of the bodily response to exercise, such as muscle efficiency and oxygenation, which augments performance.  This suggests that increasing natural dietary nitric oxide intake may act prophylactically in countering the beginning of ageing and certain heart and metabolic disorders.

The efficacy of nitric oxide might well depend on factors such as the person, including age, diet, and health and fitness status; the intensity, duration, and nature of the exercise challenge; and the dose applied and duration of the supplementation regimen.

In conclusion, citrulline is a unique amino acid that exerts its effects on cardio-metabolic health and improved muscle oxygenation during exercise. The variety of applications for which citrulline has been utilized underscores the importance of citrulline in vascular health, protein metabolism, lipid metabolism, and athletic performance.

Start adding watermelon to your post-workout routine and see if you notice a difference!