N-acetylcysteine, Alpha-Lipoic Acid, L-Glutamine, and L-Carnitine - Nutrients and HIV, part 3

Alternative Medicine Review, August, 2000 by Lyn Patrick

Glutamine

L-glutamine is found in the body in higher quantities and concentrations than any other free amino acid; along with taurine it is the most abundant amino acid in skeletal muscle.[74] Although it can be manufactured in all cells, the majority is manufactured in skeletal muscle and transported to intestinal cells, kidney, and lymphocytes, particularly under conditions of physiologic stress. When the stress is prolonged, production in skeletal muscle may not meet the demand in organ and lymphoid tissue, and a deficiency can occur.[75] Lymphocytes, macrophages, and enterocytes of the small intestine are dependent on glutamine as their primary source of fuel.[76] Numerous studies have shown benefit when parenteral glutamine was given to patients undergoing surgery, chemotherapy, or irradiation; glutamine was effective both in improving immunocompetence and preventing small bowel mucosal damage.[77-79] Glutamine also minimizes enterocolitis secondary to chemotherapy in animal models.[80]

HIV infection appears to induce glutamine deficiency, possibly as a result of the rapid turnover of immune cells that occurs in the acute and chronic stages of the infection.[81] Glutamine supplies appear to be depleted even in asymptomatic individuals; supplementation with 20 grams of glutamine daily for a month failed to normalize glutamine levels in a cohort of symptomatic HIV-positive patients.[82]

Loss of lean body mass (also known as "wasting") is common in the AIDS stage of HIV infection, and glutamine loss from skeletal muscle may further accelerate in situations where diarrhea, fever, anorexia, malabsorption, and opportunistic infections occur.[81] Total parenteral nutrition or medications given to stimulate appetite in HIV infection promote weight gain that is predominately adipose tissue or body fluid; they are not successful at promoting gain of lean body mass.[81]

Glutamine and Clinical Trials

A double-blind, placebo-controlled trial examining the effect of glutamine in HIV-infected patients was conducted on 21 HIV-positive men and women (CD4 count 1-364/[mm.sup.3]).[83] The subjects had all experienced at least five-percent unintentional weight loss since the onset of their diagnoses and were excluded if they had infectious diarrhea. Only two subjects were taking testosterone and 18 were on antiretrovirals. All patients received nutritional counseling and had bioimpedance analysis done at 0, 1, 2, and 3 months to determine body cell mass and fat mass. The patients were given 40 grams glutamine daily with an antioxidant combination that included N-acetylcysteine. For complete protocol see Table 1. The results of the study showed a significant effect of glutamine on lean body mass gain over the three-month period: the supplemented subjects gained an average of 1.8 kg lean body mass (body cell mass) over 12 weeks. The control group initially gained mass but could not sustain it, and at three months had only a net gain of 0.4 kg lean body mass. The results for the supplemented group were similar to effects gained with recombinant growth hormone (rhGH), currently the most effective FDA-approved treatment for wasting in HIV, at approximately 1/30 the cost ($31.00 vs. $1,000.00). The cost-savings is substantial. To gain 1 kg lean body mass costs approximately $9200 using rhGH; according to the results of the above study, the same amount of lean body mass could be gained with L-glutamine for $220.[84]