L-arginine is a semiessential amino acid; although the body normally makes enough of it, supplementation with additional amounts is sometimes needed. Found in foods containing protein, such as red meat, poultry and fish, as well as dairy products, L-arginine changes into nitric oxide (NO), which causes blood vessel relaxation (vasodilation).

Early evidence suggests that L-arginine may help treat medical conditions that improve with vasodilation, such as chest pain, clogged arteries (atherosclerosis), coronary artery disease, erectile dysfunction (ED), heart failure, intermittent claudication/ peripheral vascular disease, and blood vessel swelling that causes headaches (vascular headaches). L-arginine also triggers the body to make protein and has been studied for wound healing, bodybuilding, enhancement of sperm production (spermatogenesis) and prevention of wasting in people with critical illnesses.

According to Kevin Somerville, senior vice president at New Jersey-based Daesang America, the market for L-arginine has potential, but recent factors— such as the tsunami in Japan that has Affected the availability of corn—have caused the amino acid market some turmoil. “However, consumer awareness about L-arginine is pretty strong, especially in the nutrition community,” he said. “Awareness is growing, and a big part of that is because consumers are reading product labels now more than ever.”

Science

In 2010, researchers from the University of Alberta (Canada) made a discovery about the way the body fights and prevents infections. Richard Lamb and Postdoctoral fellow Virginie Mieulet found that L-arginine is necessary for the immune system to properly detect and eliminate invading bacteria. Published in the journal Science Signalling, the discovery has massive implications in understanding the role of proper nutrition—particularly essential and non-essential amino acids—in maintaining good health and preventing disease. A healthy body is full of macrophage white blood cells that seek out infections and destroy them. Prior research has established that L-arginine plays an important role in the function of macrophages, but this study has expanded upon that to reveal that Larginine also acts as a watchdog for invaders, signaling to the rest of the body to “rally up the troops,” so to speak.

L-arginine’s role as a NO precursor offers many benefits for cardiovascular health. This includes benefits in the treatment of angina, congestive heart failure, hypertension and peripheral artery disease, according to Gene Bruno, MS, MHS, the Dean of Academics for Huntington College of Health Sciences.1

• Angina: Angina pectoris is a clinical syndrome that occurs when low blood flow to the heart limits delivery of oxygen to the heart muscle during exertion. Taking 6-18 g of L-arginine daily has been shown to decrease symptoms and improve exercise tolerance and quality of life in patients ranging in angina severity from occurring only with strenuous activity, to occurring at rest.2-4 This includes a reduction in inflammation5 and improvements in flow-mediated vasodilation.6 Also, some patients with angina who have frequent attacks at rest despite treatment with standard antianginal drugs, also experienced benefits from supplementation with L-arginine.7

• Congestive Heart Failure: Congestive heart failure (CHF) is a condition in which there is an inability of the heart to provide sufficient pump action to distribute blood flow to meet the needs of the body. A six-week, randomized, double-blind trial8 found that daily supplementation with 5.6-12.6 g of L-arginine significantly improved blood flow, arterial compliance and functional status compared to placebo in patients with CHF. Another doubleblind trial found that supplementation with 15 g L-arginine daily improved kidney function in people with CHF.9

• Hypertension: Small studies in both healthy individuals and hypertensive individuals with type 2 diabetes have benefited from L-arginine supplementation. In healthy subjects, an arginine-rich diet and supplementation with L-arginine lowered blood pressure and resulted in a fall in fasting blood glucose levels.10 In type 2 diabetes mellitus and mild hypertension three grams of L-arginine per hour for 10 hours (for two days) resulted in a drop in diastolic blood pressure two hours after starting L-arginine and returning to normal within one hour of stopping the arginine.11 Other research suggest that L-arginine supplementation may also improve the effect of angiotensin converting enzyme (ACE) inhibitors in treating hypertension.12

• Peripheral Arterial Disease: Also known as peripheral vascular disease, peripheral arterial disease is the medical name given to a group of problems with poor circulation to the feet and legs. One of the first recognizable symptoms of peripheral arterial disease is intermittent claudication—basically pain or cramps in the leg muscles on walking that goes away completely after a few minutes rest. In double-blind research13, patients with intermittent claudication treated with 6 g supplemental L-arginine daily experienced improved the pain-free walking distance by 230 percent and the absolute walking distance by 155 percent. L-arginine also improved vasodilation and restored NO formation.

Further, there is some evidence that L-arginine may benefit men with ED. In a study published in the journal BJU International, for instance, 50 men with erectile dysfunction took either 5 g of L-arginine per day or a placebo. After six weeks, more men in the L-arginine group showed improvement compared to those taking the placebo.

Like the drug sildenafil citrate (Viagra), L-arginine is thought to enhance the action of NO and—in turn—relax the muscles surrounding blood vessels supplying the penis. As a result, blood vessels in the penis dilate, increasing blood flow, which may help maintain an erection. The difference in how they work is that Viagra blocks an enzyme called PDE5, which destroys NO, and L-arginine is used to make NO. Unlike Viagra, L-arginine is taken on a daily basis for ED.

Daesang’s L-arginine is manufactured by the company via its fermentation technologies, and Somerville added that this specific L-arginine has higher density than other products on the market, which helps when making a capsule or tablet. According to the company, it helps produce healthy semen and comprises 60 percent of amino acids present in semen. It is a key intermediate in the Krebs-Henseleit urea cycle and is required to be present in the body.

And as the science behind the applications of L-arginine continues, so too will its use, said Somerville. “There has been tons of evidence and work done in nutritional areas such as bodybuilding, but there still needs to be more science for other applications, such as topical uses,” he added. “The more credibility that is behind it, the better, and I can’t stress that enough. It’s possible that some day what we see happening with Dr. Oz and raspberry ketone could happen to arginine, and that will do wonders for it.”

References:

1 Bruno, G. L-Arginine: A Semiessential Amino Acid. Vitamin Retailer, 2012; 20:37-9.

2 Blum A, Porat R, Rosenschein U, et al. Clinical and inflammatory effects of dietary L-arginine in patients with intractable angina pectoris. Am J Cardiol, 1999;15:1488-90.

3 Maxwell AJ, Zapien MP, Pearce GL, et al. Randomized trial of a medical food for the dietary management of chronic, stable angina. J Am Coll Cardiol, 2002;39:37-45.

4 Ceremuzynski L, Chamiec T, Herbaczynska-Cedro K. Effect of supplemental oral L-arginine on exercise capacity in patients with stable angina pectoris. Am J Cardiol, 1997;80:331-3.

5 Blum A, Porat R, Rosenschein U, et al. Clinical and inflammatory effects of dietary L-arginine in patients with intractable angina pectoris. Am J Cardiol, 1999;15:1488-90.

6 Maxwell AJ, Zapien MP, Pearce GL, et al. Randomized trial of a medical food for the dietary management of chronic, stable angina. J Am Coll Cardiol, 2002;39:37-45.

7 Blum A, Porat R, Rosenschein U, et al. Clinical and inflammatory effects of dietary L-arginine in patients with intractable angina pectoris. Am J Cardiol, 1999;15:1488-90.

8 Rector TS, Bank A, Mullen KA, et al. Randomized, double-blind, placebo controlled study of supplemental oral L-arginine in patients with heart failure.
Circulation, 1996;93:2135-2141.

9 Watanabe G, Tomiyama H, Doba N. Effects of oral administration of L-arginine on renal function in patients with heart failure. J Hypertens, 2000;18:229-234. 

10 Siani A, Pagano E, Iacone R, et al. Blood pressure and metabolic changes during dietary L-arginine supplementation in humans. Am J Hypertens, 2000;13:547-51.

11 Huynh NT, Tayek JA. Oral arginine reduces systemic blood pressure in type 2 diabetes: its potential role in nitric oxide generation. J Am Coll Nutr, 2002;21:422-7.

12 Cheng JW, Balwin SN. L-arginine in the management of cardiovascular diseases. Ann Pharmacother, 2001;35:755-64.

13 Boger RH, Bode-Boger SM, Thiele W, et al.

Restoring vascular nitric oxide formation by L-arginine improves the symptoms of intermittent claudication in patients with peripheral arterial occlusive disease. J Am Coll Cardiol, 1998;32:1336-44.

FOR MORE INFORMATION:

■ Daesang America, (201) 488-4010