L-Arginine Supplements Review & Information

Review And Details On L-Arginine
( 09/12/2004 )

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Supplement	L-Arginine

Description	Arginine is an amino acid and is also referred to as "L-Arginine" (the L stands for "levo" and designates the amino acid as naturally occurring and distinguishes from the D or " " synthetic amino acids.).

Claims	Protection from heart disease Reduces cholesterol Lowers blood pressure Improves poor circulation

Theory	Arginine is a key component of the nitric oxide pathway – and important cascade of reactions involved in vasodilation and related to cardiovascular function. Arginine supplements have been associated with reductions in symptoms associated with coronary artery disease and may be capable of slowing the progression of atherosclerosis In the body, arginine serves as the substrates for the nitric oxide synthase enzyme, which catalyzes the oxidation of arginine to produce citrulline and nitric oxide (NO). In the cells that line the blood vessels (endothelium cells), nitric oxide production causes vasodilation (opening of the vessels). NO is involved in the overall regulation of systemic vascular resistance, where it inhibits the adherence of cells and foreign substances to the blood vessel walls and helps suppress the overgrowth of smooth muscle cells in the lining of the vessels. Because humans can synthesize arginine, it has been classified as a non-essential amino acid. Recent evidence suggests that the rate of synthesis of arginine in the body is insufficient for optimal health – a situation which would re-classify arginine as a semi-essential or conditionally essential amino acid.

Scientific Support	In people with elevated cholesterol levels, it is common to see a reduced ability of the endothelium to produce NO and, therefore, to dilate effectively. In addition, because NO production may be limited, blood cells such as monocytes and platelets are more likely to attach themselves to the inner vessel wall and lead to blockages. Arginine supplements (8-21 grams per day) have been shown to restore endothelial vasodilation in the coronary arteries of people with high cholesterol and reduce the ability of blood cells to adhere to the vessel walls. Improvements in coronary artery blood flow and reductions in myocardial ischemia and walking pain due to claudication have been noted with arginine supplements (9-14 g/day).

Safety	Arginine supplements have been used safely in patients with heart disease in doses up to more than 20 grams per day.

Value	For those individuals at risk for coronary artery disease, including those who experience ischemia due to reduced blood flow and oxygen delivery, arginine supplements may be an effective strategy for improving circulation to the heart and other affected areas (such as vessels in the calves).

Dosage	A daily arginine requirement has been calculated to be approximately 8 grams per day (based on calculations for a 70-kg person). Since the average American diet contains only about 5 grams of arginine per day, there would appear to be a deficit in intake versus requirements. Importantly, the primary dietary sources of arginine, like all amino acids, are meats and other high protein foods (nuts, eggs).
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References	1. Alexander JW, Levy A, Custer D, Valente JF, Babcock G, Ogle CK, Schroeder TJ. Arginine, fish oil, and donor-specific transfusions independently improve cardiac allograft survival in rats given subtherapeutic doses of cyclosporin. JPEN J Parenter Enteral Nutr. 1998 May-Jun;22(3):152-5. 2. Brown SA, Langford K, Tarver S. Effects of certain vasoactive agents on the long-term pattern of blood pressure, heart rate, and motor activity in cats. Am J Vet Res. 1997 Jun;58(6):647-52. 3. Chaloupecky V, Hucin B, Tlaskal T, Kostelka M, Kucera V, Janousek J, Skovranek J, Sprongl L. Nitrogen balance, 3-methylhistidine excretion, and plasma amino acid profile in infants after cardiac operations for congenital heart defects: the effect of early nutritional support. J Thorac Cardiovasc Surg. 1997 Dec;114(6):1053-60. 4. Chin-Dusting JP, Kaye DM, Lefkovits J, Wong J, Bergin P, Jennings GL. Dietary supplementation with L-arginine fails to restore endothelial function in forearm resistance arteries of patients with severe heart failure. J Am Coll Cardiol. 1996 Apr;27(5):1207-13. 5. Dadmarz M, v d Burg C, Milakofsky L, Hofford JM, Vogel WH. Effects of stress on amino acids and related compounds in various tissues of fasted rats. Life Sci. 1998;63(16):1485-91. 6. de Lorgeril M, Salen P, Monjaud I, Delaye J. The 'diet heart' hypothesis in secondary prevention of coronary heart disease. Eur Heart J. 1997 Jan;18(1):13-8. 7. Fraser GE. Diet and coronary heart disease: beyond dietary fats and low-density-lipoprotein cholesterol. Am J Clin Nutr. 1994 May;59(5 Suppl):1117S-1123S. 8. Fraser GE. Nut consumption, lipids, and risk of a coronary event. Clin Cardiol. 1999 Jul;22(7 Suppl):III11-5. 9. Gnadinger MP, Weidmann P, Rascher W, Lang RE, Hellmuller B, Uehlinger DE. Plasma arginine-vasopressin levels during infusion of synthetic atrial natriuretic peptide on different sodium intakes in man. J Hypertens. 1986 Oct;4(5):623-9. 10. Hayakawa H, Raij L. Nitric oxide synthase activity and renal injury in genetic hypertension. Hypertension. 1998 Jan;31(1 Pt 2):266-70. 11. Hayashi T, Fukuto JM, Ignarro LJ, Chaudhuri G. Gender differences in atherosclerosis: possible role of nitric oxide. J Cardiovasc Pharmacol. 1995 Nov;26(5):792-802. 12. He H, Kimura S, Fujisawa Y, Tomohiro A, Kiyomoto K, Aki Y, Abe Y. Dietary L-arginine supplementation normalizes regional blood flow in Dahl-Iwai salt-sensitive rats. Am J Hypertens. 1997 May;10(5 Pt 2):89S-93S. 13. Ikeda K, Nara Y, Tagami M, Yamori Y. Nitric oxide deficiency induces myocardial infarction in hypercholesterolaemic stroke-prone spontaneously hypertensive rats. Clin Exp Pharmacol Physiol. 1997 May;24(5):344-8. 14. Laurant P, Demolombe B, Berthelot. Dietary L-arginine attenuates blood pressure in mineralocorticoid-salt hypertensive rats. Clin Exp Hypertens. 1995 Oct;17(7):1009-24. 15. Lou H, Kodama T, Wang YN, Katz N, Ramwell P, Foegh ML. L-arginine prevents heart transplant arteriosclerosis by modulating the vascular cell proliferative response to insulin-like growth factor-I and interleukin-6. J Heart Lung Transplant. 1996 Dec;15(12):1248-57. 16. Manning RD Jr, Hu L, Reckelhoff JF. Role of nitric oxide in the arterial pressure and renal adaptations to long-term changes in sodium intake. Am J Physiol. 1997 Apr;272(4 Pt 2):R1162-9. 17. Rajamohan T, Kurup PA. Lysine: arginine ratio of a protein influences cholesterol metabolism. Part 1--Studies on sesame protein having low lysine: arginine ratio. Indian J Exp Biol. 1997 Nov;35(11):1218-23. 18. Siani A, Pagano E, Iacone R, Iacoviello L, Scopacasa F, Strazzullo P. Blood pressure and metabolic changes during dietary L-arginine supplementation in humans. Am J Hypertens. 2000 May;13(5 Pt 1):547-51. 19. Stechenko LO, Sahach VF, Tkachenko MM, Skybins'ka TR, Andriienko TV. The effect of L-arginine on the ultrastructure of atrial cardiomyocytes in experimental hypercholesterolemia. Fiziol Zh. 1999;45(1-2):72-9. 20. Wu G, Flynn NE, Flynn SP, Jolly CA, Davis PK. Dietary protein or arginine deficiency impairs constitutive and inducible nitric oxide synthesis by young rats. J Nutr. 1999 Jul;129(7):1347-54.

(article courtesy of supplementwatch.com)