RESUMO
It has been suggested that the administration of certain nutrients may improve the immune response of patients with cancer. Experimental studies have shown that deficiencies in specific amino acids have a worse effect on humoral immunity than they do on cell-mediated immunity because they impair antibody synthesis. Here, arginine plays a particularly important role, and research with several experimental and human tumor models to determine the therapeutic utility of this amino acid is under way. In this paper, we review current literature on the use of arginine as pharmacologic nutritional support for cancer patients. Dietary supplementation with arginine has been shown to benefit these patients by reducing the growth of transplantable tumors, the incidence of metastases, and the tumor-producing potential of carcinogens. However, results observed in humans have given rise to controversy regarding the optimal dosage of arginine supplementation and the types of cancer best treated with amino acids. Further prospective and randomized studies will be necessary in order to determine the proper utilization and the therapeutic benefits of such dietary supplementation.