PHYSIOLOGIC EFFECTS OF GLUTAMINE SUPPLEMENTATION IN HUMANS

Glutamine Supplementation and Glucose Metabolism

The potential clinical benefits of glutamine are derived from glutamine’s physiologic and metabolic roles as shown in Table 14.2. Because critical illness is associated with increased glucose production, hyperglycemia, and insulin resistance and glutamine is an important precursor for glucose production, it was hypothesized that glutamine could attenuate these alterations in glucose metabolism. In one study of 114 patients with multiple trauma, postsurgical complications, or pancreatitis randomized to either intravenous alanyl-glutamine (Ala-Gln) or intravenous alanine and proline (Ala + Pro), patients receiving Ala-Gln had significantly less hyperglycemia, less requirement for insulin therapy, and fewer nosocomial infections when compared with the Ala + Pro group

TABLE 14.2

Clinical Outcomes Demonstrating Improvements in Patients Supplemented with Glutamine

^a In some studies.

(Dechelotte et al. 2006). The reduction in infections was mainly a result of decreased incidence of pneumonia. In a smaller study of patients with multiple trauma, supplementation with parenteral Ala-Gln led to a decrease in endogenous insulin secretion, less insulin resistance in the fasting state, and better insulin-mediated glucose disposal (Bakalar et al. 2006). In a Spanish multicenter study, administration of Ala-Gln dipeptide-supplemented total parenteral nutrition (TPN) led to statistically though not clinically significant decreases in plasma glucose concentration (149 ± 46 mg/dL with supplementation vs. 155 ± 51 mg/dL without, p < 0.04) and hourly insulin dose (4.3 ± 3.3 IU with supplementation vs. 4.7 ± 3.7 IU without, p < 0.001) when compared with TPN alone (Grau et al. 2011). In addition, insulin administration for the same level of glycemia was 54% less in the Ala-Gln supplemented group.