Health Benefits Of Arginine

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Arginine is a semiessential amino acid whose indispensability sets in when critical illness and severe trauma occur; adults can produce this amino acid through the biosynthetic pathway, although its consumption from diet is still imperative to sustain satisfactory physiological levels our bodily functions require, especially in preterm infants who are incapable of natural arginine synthesis and in critically ill individuals with poor nutritional status and certain physical conditions. Similar to any amino acid, arginine is involved with protein synthesis and also increases growth hormone secretion, hence regulating immune function. Furthermore, arginine serves as the precursor of creatine, which in turn is used by the body for the growth and energy metabolism of muscles, nerve, and testes. ^[1] Arginine is a precursor as well for the synthesis of glutamate, polyamines, creatine, agmatine, proline and urea.

In general, a healthy person can easily replenish one’s own arginine supply, but once metabolic needs increase due to sickness and exceed more than what our arginine-producing mechanism can meet, extra amounts from diet and supplements can remedy the demand. Very good sources of arginine include turkey, pork, chicken, pumpkin seeds, soybeans, nuts (including peanuts) and egg white. ^[2]

Arginine and the Production of Nitric Oxide

There are many reasons why arginine is unanimously considered physiologically important in our bodies since this amino acid participates in numerous metabolic processes, but the foremost perhaps would be its role as the precursor (“building block”) for the body’s creation of nitric oxide. Nitric oxide serves as a neurotransmitter in the central nervous system, particularly in the brain, as a mediator of host defense in the immune system, and as a vasodilator and endogenous antiatherogenic molecule in the cardiovascular system. Nitric oxide is the chief form of the endothelium-derived relaxing factor as well. Böger (2007) notes that an intake of reasonably large doses of L-arginine either through our diets or intravenously leads to enhanced nitric oxide production in individuals exhibiting impaired endothelial function at baseline and to improved cardiovascular disease symptoms, as demonstrated in a number of controlled clinical trials. ^[3] Studies have demonstrated that systemic or oral intake of arginine enhances cardiovascular function, reduces blood pressure and decreases myocardial ischemia among patients with coronary artery disease. It also reduces renal vascular resistance in patients with high blood pressure and normal or insufficient kidney function. ^[1]

Arginine, Hormones, and Exercise

A number of recent studies have demonstrated that L-arginine, orally administered, at a tolerated dose range of 5-9 g, potently stimulates a dose-dependent increase in resting growth hormone responses. Notably, at least 100% of resting growth hormone levels is achieved upon oral arginine intake. ^[4] Furthermore, McConell (2007) reported that administration of L-arginine improves endothelial function in a range of disease states and elevates the levels of hormones such as plasma insulin, catecholamines, growth hormone, glucagon and prolactin. These in turn influence metabolism. Research evidence also points to L-arginine boosting the positive effects of exercise on capillary growth in muscles and insulin sensitivity. ^[5]

To date, a considerably good amount of data supports the claim that arginine can be regarded as an effective ergogenic aid or performance enhancer. The double-blind, placebo-controlled study of Camic et al. (2010), for instance, randomized fifty college-aged men into three groups, namely, those on placebo, on 1.5 g arginine, and on 3.0 g arginine treatment, to determine the effect of daily 4-week oral administration of arginine-based supplements on the physical working capacity at the fatigue threshold (PWCFT), which measures the ability of an individual to resist fatigue and hence his or her functional capacity. Results revealed significant mean increases in PWCFT among subjects on L-arginine supplementation but no change for the placebo group. ^[6]

Arginine and Wound Healing

Because arginine plays a role in protein synthesis, in cell signaling via nitric oxide production and in cell proliferation, its participation in wound healing comes as a no surprise. In fact, several studies have concluded that arginine supplementation can lead to normalization or improvement of wound healing, making supplementation with arginine either on its own or in combination with other amino acids a very reasonably attractive treatment option in the management and care of critically ill or traumatized patients. ^[7] In artificial incisional wounds in rodents and humans, arginine boosts wound strength and collagen deposition, but as of today, concrete data from robust clinical trials / human studies are still limited as regards the recommended safe dose of arginine to fulfill the metabolic necessities during wound healing and the efficacy of arginine supplementation in improving recovery from acute and chronic wounds. ^[8]

Arginine and Aging

The potential anti-aging benefits of arginine come from the various health-promoting effects this amino acid renders in the body, including its ability to reduct risk of heart and vascular disease, supporting healthy erectile function, immune response improvement and suppression of gastric hyperacidity. According to a number of human and experimental animal studies, exogenous L-arginine intake induces several pharmacological effects when administered in doses larger than what can be obtained through normal dietary consumption. ^[9]