Keep reading to see what L-citrulline is and why it promises to be so beneficial to your health. Plus: Discover creative ways to up your intake with plenty of sweet, juicy watermelon.
What is L-citrulline?
“L-citrulline is a non-protein amino acid found in the flesh and rind of watermelon that may have promising health results,” says Kim Rose, RDN, CDCES, CNSC, a Florida-based dietitian. While some amino acids include proteins, L-citrulline is not one of them. That said, a 2013 review in The international journal of applied and basic nutritional sciences explains that L-citrulline”stimulates protein synthesis in skeletal muscle‘ and ‘could play a central role in maintaining protein homeostasis’, so it’s not a complete misfire in that regard.
L-citrulline is also a non-essential amino acid, which means your body makes it on its own. However, it is produced at lower levels than you would get from eating watermelon or through supplementation.
The health benefits of L-citrulline
“L-citrulline may support heart health by lowering blood pressure; increase blood flow and reduce heart rate during and after a workout, respectively; and can help decrease cognitive decline,” says Rose.
L-citrulline increases vasodilation, ie the dilation of blood vessels, which lowers blood pressure and improves blood flow. According to a 2018 Nutrients article, it works by increasing the bioavailability of arginine, which “subsequently leads to elevations in nitric oxide synthesis”. (Nitric oxide is a compound that relaxes constriction in the small muscles of blood vessels.) Over time, greater consumption of L-citrulline – via watermelon as well as by other vasodilating foods— may help reduce the risk of high blood pressure and heart disease.
Hence, a study published in theJournal of Agricultural and Food Chemistry demonstrated the functional benefits of L-citrulline after exercise. Although it used a small sample size, the study found that athletes who drank either 500 milliliters of pure watermelon juice (1.17 grams of L-citrulline) or watermelon juice fortified with 4.83 Additional grams of L-citrulline helped reduce not only the participants’ heart rate recovery, but also their muscle soreness after 24 hours compared to a placebo group.
Finally, Rose mentions a 2020 study published in Alzheimer’s and dementiain which researchers found that L-citrulline supplementation in mice may alter cognitive decline since nitric oxide “plays an important role in synaptic plasticity, learning, and memory.”
Simply put, thanks to its abundant L-citrulline content, everyone’s favorite summer fruit works overtime to support an array of impressive functions throughout the body, all while delighting your taste buds and keeping you hydrated.
How to Increase Your L-Citrulline Intake
Again, watermelon is your best bet for replenishing this amino acid through the diet, although supplementation is also an option to increase your intake even further or when watermelon is no longer in season. . (Note: As always, consult a trusted healthcare professional before adding any new supplements to your regimen.)
Although there are currently no specific intake recommendations for L-citrulline, Rose shares that a two-cup serving of watermelon (which can contain 286 to 1,266 milligrams, according to quality and breed) “may help support vascular health and maintain healthy blood circulation.” She continues to say that for further benefits, the exact amounts recommended are still being researched.
In any case, favoring watermelon in your diet this summer is a safe bet to progress in the right direction. Luckily, Rose shares several creative ways to enjoy them that go beyond simple cutting, such as: