l-Carnosine supplementation attenuated fasting glucose, triglycerides, advanced glycation end products, and tumor necrosis factor-α levels in patients with type 2 diabetes: a double-blind placebo-controlled randomized clinical trial.

Considering the pathologic importance of metabolic disturbances, advanced glycation end products (AGEs), and chronic inflammation in diabetes mellitus and ameliorating potentials of l-carnosine in hampering these detritions and because these effects have not been investigated in patients with type 2 diabetes (T2D) so far, we conducted the current study. We hypothesized that l-carnosine would improve glycemic control, lipid profile, AGE, soluble receptor of AGEs (sRAGE), and inflammatory markers. In a randomized, double-blind, placebo-controlled clinical trial, 54 patients with T2D were recruited and assigned into either intervention group (n=27, receiving 2 capsules of l-carnosine 500 mg each) or control group (n=27). Blood samples and dietary intakes information were collected at baseline and after 12 weeks of intervention. l-Carnosine supplementation resulted in significant decrease in fat mass and an increase in fat-free mass in the intervention group compared with the placebo group (1.5% and 1.7%, respectively) (P<.05). A significant reduction in fasting blood glucose (13.1 mg/dL); glycated hemoglobin (.6%); and serum levels of triglycerides (29.8 mg/dL), carboxymethyl lysine (91.8 ng/mL), and tumor necrosis factor-α was detected in the l-carnosine group compared with the placebo group (P<.05). In the l-carnosine group, a significant reduction in serum pentosidine levels (2.8 ng/mL) was observed compared with those at baseline (P<.05). No significant differences were observed in dietary intake, body mass index, systolic and diastolic blood pressure, fasting insulin levels, homeostasis model assessment of insulin resistance and secretion, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, sRAGE, interleukin (IL)-6, and IL-1β levels between the groups after adjusting for baseline values and covariates (P>.05). Collectively, l-carnosine lowered fasting glucose, serum levels of triglycerides, AGEs, and tumor necrosis factor-α without changing sRAGE, IL-6, and IL-1β levels in T2D patients.