l-Citrulline Supplementation: Impact on Cardiometabolic Health.
Diminished bioavailability of nitric oxide (NO), the gaseous signaling molecule involved in the regulation of numerous vital biological functions, contributes to the development and progression of multiple age- and lifestyle-related diseases. While l-arginine is the precursor for the synthesis of NO by endothelial-nitric oxide synthase (eNOS), oral l-arginine supplementation is largely ineffective at increasing NO synthesis and/or bioavailability for a variety of reasons. l-citrulline, found in high concentrations in watermelon, is a neutral alpha-amino acid formed by enzymes in the mitochondria that also serves as a substrate for recycling l-arginine. Unlike l-arginine, l-citrulline is not quantitatively extracted from the gastrointestinal tract (i.e., enterocytes) or liver and its supplementation is therefore more effective at increasing l-arginine levels and NO synthesis. Supplementation with l-citrulline has shown promise as a blood pressure lowering intervention (both resting and stress-induced) in adults with pre-/hypertension, with pre-clinical (animal) evidence for atherogenic-endothelial protection. Preliminary evidence is also available for l-citrulline-induced benefits to muscle and metabolic health (via vascular and non-vascular pathways) in susceptible/older populations. In this review, we examine the impact of supplementing this important urea cycle intermediate on cardiovascular and metabolic health outcomes and identify future directions for investigating its therapeutic impact on cardiometabolic health.
['Allerton|Timothy D|TD|', 'Proctor|David N|DN|', 'Stephens|Jacqueline M|JM|', 'Dugas|Tammy R|TR|', 'Spielmann|Guillaume|G|', 'Irving|Brian A|BA|0000-0002-4131-9523']
D000818:Animals D000894:Anti-Inflammatory Agents, Non-Steroidal D000959:Antihypertensive Agents D000975:Antioxidants D002956:Citrulline D003925:Diabetic Angiopathies D019587:Dietary Supplements D004730:Endothelium, Vascular D019317:Evidence-Based Medicine D006801:Humans D006973:Hypertension D007004:Hypoglycemic Agents D007333:Insulin Resistance D024821:Metabolic Syndrome D008954:Models, Biological D055948:Sarcopenia D059289:Vascular Stiffness D014665:Vasodilator Agents
supplements nitric oxide watermelon mitochondria enterocytes liver interventions muscle therapeutics adipocytes aging arginine cardiovascular disease diabetes endothelial function flow mediated dilation hypertension immune cells inflammation insulin resistance obesity