Blood pressure and metabolic changes during dietary L-arginine supplementation in humans

Dietary L-arginine supplementation has been proposed to reverse endothelial dysfunction in such diverse pathophysiologic conditions as hypercholestero lemia, coronary heart disease, and some forms of animal hypertension. In pa rticular, chronic oral administration of L-arginine prevented the blood pre ssure rise induced by sodium chloride loading in salt-sensitive rats. To in vestigate the effects of L-arginine-rich diets on blood pressure and metabo lic and coagulation parameters we performed a single-blind, controlled, cro ssover dietary intervention in six healthy volunteers. The subjects (aged 3 9 +/- 4 years, body mass index [BMI] 26 +/- 1 kg/m(2),mean +/- SEM) receive d, in random sequence, three different isocaloric diets, each for a period of 1 week (Diet 1: control; Diet 2: L-arginine enriched by natural foods; D iet 3: identical to Diet 1 plus oral L-arginine supplement). Sodium intake was set at a constant level (about 180 mmol/day) throughout the three study periods. A blood pressure decrease was observed with both L-arginine-rich diets (Diet 2 v 1, SEP: -6.2 mm Hg [95% CI: -0.5 to -11.8], DBP: -5.0 mm Hg [-2.8 to -7.2]; Diet 3 v 1, SEP: -6.2 mm Hg [-1.8 to -10.5], DBP: -6.8 mm Hg [-3.0 to -10.6]). A slight increase in creatinine clearance (P = .07) an d a fall in fasting blood glucose (P = .008) occurred after Diet 3 and, to a lesser extent, after Diet 2. Serum total cholesterol (P = .06) and trigly ceride (P = .009) decreased and HDL cholesterol increased (P = .04) after D iet 2, but not after Diet 3. These results indicate that a moderate increase in L-arginine significantly lowered blood pressure and affected renal function and carbohydrate metabo lism in healthy volunteers. (C) 2000 American Journal of Hypertension, Ltd.