L-Arginine and L-Citrulline in Sports Nutrition and Health

Amino acids are used for the synthesis of body proteins and other nitrogenous metabolites in cell signaling, and as regulators of hormone secretion and nutrient metabolism. Arginine and citrulline are especially important in the control of hemodynamics and whole-body homeostasis, as both participate in multiple metabolic pathways and play vital roles in maintaining the health and integrity of skeletal and cardiac muscles. Arginine contributes to the release of growth hormone and creatine synthesis, both of which positively improve muscle mass and strength. Arginine is also required for the production of nitric oxide, which improves vascular function and regulates growth and detection of changes in mechanical loading of skeletal muscle. Indeed, arginine supplementation positively contributes to heart and muscle health as well as the maintenance of exercise capacity. Citrulline is converted into arginine in almost all cell types and thus can be used to prevent arginine and nitric oxide deficiencies under various physiological and pathological conditions. Further, citrulline aids in the detoxification of ammonia, which helps to reduce fatigue and improve exercise performance. Collectively, arginine and citrulline are crucial for enhancing sports nutrition in humans. 2013 Elsevier Inc. All rights reserved.

L-Arginine and L-Citrulline in Sports Nutrition and Health Chapter