Effect of synbiotic bread containing lactic acid on glycemic indicators, biomarkers of antioxidant status and inflammation in patients with type 2 diabetes: a randomized controlled trial

BACKGROUND: The aim of this randomized, double-blinded, controlled trial was to investigate the effect of daily consumption of a synbiotic bread containing lactic acid on glycemic status, antioxidant biomarkers and inflammation in patients with type 2 diabetes (T2D). METHODS: T2D patients, aged 20 to 60 years, were randomly assigned to consume synbiotic + lactic acid (n = 30), synbiotic (n = 30), lactic acid (n = 30), or control (n = 30) bread for 8 weeks. Patients consumed bread 3 times a day in a 40 g package for a total of 120 g/day. Glycemic status, antioxidant capacity, and serum hs-CRP were assessed before and after the intervention. RESULTS: Of a total of 120 patients that were included in the study, 100 completed the trial. In the adjusted analysis, it was found that consumption of synbiotic + lactic acid bread caused a significant decrease in HbA1c compared to the control bread (− 0.41 ± 0.33 vs 0.004 ± 0.10%, respectively; P < 0.001), while it significantly increased serum superoxide dismutase (SOD) (0.87 ± 1.14 vs. 0.18 ± 0.85 mmol/L, P = 0.02). Also, changes in glutathione peroxidase (GSH-Px) were significantly higher following the consumption of synbiotic + lactic acid bread than lactic acid bread. However, it had no significant effect on fasting plasma glucose, serum insulin, and total antioxidant capacity. CONCLUSION: Overall, daily consumption of a synbiotic bread containing lactic acid for 8 weeks had beneficial effects on HbA1c, SOD, and GSH-Px among T2D patients. Trial registration This study was registered in Iranian Registry of Clinical Trials with number: IRCT201505242709N33 (Registration date: 2015-11-23, http://www.irct.ir/trial/2544)