The Effects of Lactobacillus casei on Glycemic Response, Serum Sirtuin1 and Fetuin-A Levels in Patients with Type 2 Diabetes Mellitus: A Randomized Controlled Trial

BACKGROUND: Type 2 diabetes mellitus (T2DM) is related to the gut microbiota with numerous molecular mechanisms. Modulating the gut microbiota by probiotics could be effective in management of T2DM. The aim of the present trial was to evaluate the effect of Lactobacillus casei on glycemic control and serum sirtuin1 (SIRT1) and fetuin-A in patients with T2DM. METHODS: Forty patients with T2DM (n = 20 for each group) were divided into intervention (probiotic) and placebo groups. The intervention group received a daily capsule containing 10(8) cfu of L. casei for eight weeks. The patients in placebo group took capsules containing maltodextrin for the same time duration. Anthropometric measurements, dietary intake questionnaires, and blood samples were collected, and the patients were assessed by an endocrinologist at the beginning and at the end of the trial. RESULTS: Fasting blood sugar, insulin concentration, and insulin resistance significantly decreased in probiotic group compared with placebo group (-28.32 [-50.23 to -6.41], 0.013; -3.12 [-5.90 to -0.35], 0.028; -32.31 [-55.09 to -9.54], 0.007, respectively). Moreover, HbA1c reduced after intervention, but the reduction was not significant (-0.45 [-0.96 to 0.05], 0.077). In comparison with placebo, the L. casei supplementation significantly increased SIRT1 and decreased fetuin-A levels at the end of the trial (0.52 [0.026 to 1.02], 0.040; -17.56 [-32.54 to -2.58], 0.023, respectively). CONCLUSION: L. casei supplementation affected SIRT1 and fetuin-A levels in a way that improved glycemic response in subjects with T2DM. Affecting the SIRT1 and fetuin-A levels introduces a new known mechanism of probiotic action in diabetes management.