Arginine

Okamoto Y, Okano K, Izuishi K, Usuki H, Wakabayashi H, Suzuki Y. Attenuation of the systemic inflammatory response and infectious complications after gastrectomy with preoperative oral arginine and omega-3 fatty acids supplemented immunonutrition. World J Surg. 2009 Sep;33(9):1815-21.
In this randomized study, 60 patients with gastric cancer received immune-enhanced formulas supplemented with arginine and omega-3 fatty acids (immune-enhancing diet, ID group) or standard formulas (conventional diet, CD group) for 7 days before they underwent gastrectomy. The postoperative outcome was determined based on infectious and noninfectious complications, and duration of systemic inflammatory response syndrome (SIRS). Researchers reported a significant reduction in the incidence of postoperative infectious complications in the ID group (6%) (p < 0.05) compared to those in the CD group (28%). The duration of SIRS in the ID group (0.77 +/- 0.9 days) was also significantly (p < 0.05) shorter than the CD group (1.34 +/- 1.45 days). Whereas the lymphocyte and CD4(+)T-cell counts significantly decreased (p < 0.05) in both groups, the number of CD4(+)T-cells on preoperative day 1 and postoperative day 7 was significantly (p < 0.05) higher in the ID group compared to the CD group.
Preoperative oral immune-enhancing formulas containing arginine and omega-3 fatty acids may benefit patients with gastric cancer by decreasing postoperative infectious complications.

Wilson AM, et al. L-arginine supplementation in peripheral arterial disease: no benefit and possible harm. Circulation. Jul 10 2007;116(2):188-195.Because arginine supplementation provides short-term benefits to patients with peripheral artery disease (PAD), the objective of the Nitric Oxide in Peripheral Arterial Insufficiency (NO-PAIN) study, a prospective, randomized, double-blind, placebo-controlled trial, was to assess its long-term benefits. After 6 months of arginine (3 g/day) or placebo, 133 participants with PAD were examined for claudication distance and NO availability. Reduced improvements in NO, flow-mediated vasodilation, and walking distance were detected in participants receiving arginine as compared to the placebo group. The discordance between previously reported short-term studies and this long-term study may be due to unknown counterregulatory mechanisms such as arginase induction.

Lucotti P, et al. Beneficial effects of a long-term oral L-arginine treatment added to a hypocaloric diet and exercise training program in obese, insulin-resistant type 2 diabetic patients. Am J Physiol Endocrinol Metab. Nov 2006;291(5):E906-912.
The effect of arginine supplementation (8.3 g/day) was assessed in this study of 33 middle-aged, obese, type 2 diabetic participants undergoing an exercise training program and a hypocaloric diet. After 21 days, participants receiving arginine supplementation showed greater improvements in body composition as assessed by reduced fat mass and waste circumference as well as improved glucose tolerance as compared to the control group. Long-term studies are required to determine if arginine supplementation further reduces cardiovascular disease in these subjects.

Matsuda A, Takasaki H, Suzuki H, et al. Preoperative Oral Immune-Enhancing Nutritional Supplementation Corrects Th1/Th2 Imbalance in Patients Undergoing Elective Surgery for Colorectal Cancer. Dis Colon Rectum 2006 ;49(4):507-16.
Thirty-six patients with colorectal cancer scheduled for surgery were randomly divided into two groups; 19 patients received preoperative 750ml/day oral supplementation containing arginine, omega-3 fatty acids and ribonucleic acid for five days. The control group did not receive oral supplementation pre or post-operatively. Peripheral blood samples were drawn on the morning of surgery and 3, 7 and 14 days postoperatively. Flow cytometry determined the proportions of CD4+ T cells producing intracellular cytokines. Th1/Th2 balance shifted to Th2 dominance in the control group. Th2 dominance is associated with immune suppression in the cancer bearing state preoperatively, and surgical stress postoperatively. The supplemented group maintained the preoperative levels of Th1/Th2 until day 14. Preoperative immunonutrition may correct the altered Th1/Th2 balance in the preoperative cancer-bearing state and postoperatively.

Palloshi A, Fragasso G, Piatti P, et al. Effect of oral L-arginine on blood pressure and symptoms and endothelial function in patients with systemic hypertension, positive exercise tests, and normal coronary arteries. Am J Cardiol. 2004;93(7):933-935.
Thirteen patients with grade 2 to 3 hypertension, microvascular angina and positive exercise tests received 2 grams of oral Arginine for 4 weeks. The patients were on full antihypertensive and antianginal therapy aimed at optimal control of blood pressure. Compared with baseline measurements, Arginine supplementation significantly decreased mean systolic blood pressure at rest (166 +/- 27 to 146 +/- 12 mm Hg; p<0.005). The frequency of angina attacks decreased from 12 +/- 3 to 4 +/- 1 per week, and nitroglycerin use decreased from 9 +/ 2 to 3 +/- 1 per week. The patients self-rated overall quality of life increased. (p values < 0.001) The authors suggest that Arginine may represent a useful therapeutic option for hypertension and microvascular angina, However, this study is based on a small sample size. Large well-designed clinical trials are needed to confirm this effect.