Clinical Observations: Arginine vs Protein Supplementation in HIV-infected Men

Abstract

Background: The enhancement of immune function and nutritional status is a challenge in the care of HIV-infected persons. The semiessential amino acid, L-arginine, has been shown to enhance immune function by promoting T-cell proliferation and nitrogen retention in animal and human models. Objective: We studied the effect of three levels of arginine supplementation in isonitrogenous doses on immune function and parameters commonly used to assess nutritional status. The side effect profile of oral arginine in HIV-infected male volunteers was also assessed. Design: The study design was experimental double-blinded with 19 HIV patients from an outpatient clinic randomized to consume 20 g (n = 7), 10 g (n = 6), or 0 g (n = 6) of arginine per day for four weeks. Protein powder was added to 0 g and 10 g arginine doses to make them isonitrogenous with the 20 g arginine dose. To assess immune function, peripheral blood CD4 T-cell numbers and viral loads were obtained at week 0, 4, and 8. The parameters used to assess nutritional status included weight, body mass index (BMI), body cell mass (BCM), albumin, and body fat at week 0, week 4, and week 8. A series of weekly (weeks 0 to 4) 3-day diet records was collected from each patient, and dietary protein, energy, and dietary arginine were determined. Results: Three-day diet records collected from each patient indicated that compliance was good, and the side-effect profile of the oral arginine supplement was favorable during the one-month period. In the three groups, the following were identified: weight gain was 1.1 kg at week 4 for the 20 g arginine group, -0.09 kg in the 10 g arginine group, and -0.45 kg in the 0 g arginine group (p > .05). There was an increase in BCM at week 4 in all three supplemented groups with a larger increase (1% vs 0.5%) in BCM from baseline to week 4 for the patients treated with protease inhibitors vs other antiretroviral agents (p > .05). Viral load and CD4 lymphocyte counts were not changed in the three groups with supplementation, Conclusions: The study findings suggest that enrichment of a diet with protein or arginine may improve BCM and supplementation with arginine 20 g per day may safely increase body weight. However, arginine or protein supplementation did not significantly changes analyzed nutritional or immunological parameters in this population. Further study needs to consider a larger sample and a longer study duration to determine if changes are statistically significant.