A randomized, double-blind, placebo-controlled, clinical trial on probiotic soy milk and soy milk: effects on epigenetics and oxidative stress in patients with type II diabetes

This clinical trial aimed to discover the effects of probiotic soy milk and soy milk on MLH1 and MSH2 promoter methylation, and oxidative stress among type II diabetic patients. Forty patients with type II diabetes mellitus aged 35–68 years were assigned to two groups in this randomized, double-blind, controlled clinical trial. Patients in the intervention group consumed 200 ml/day of probiotic soy milk containing Lactobacillus plantarum A7, while those in the control group consumed 200 ml/d of conventional soy milk for 8 weeks. Fasting blood samples, anthropometric measurements, and 24-h dietary recalls were collected at the baseline and at the end of the study, respectively. Probiotic soy milk significantly decreased promoter methylation in proximal and distal MLH1 promoter region (P < 0.01 and P < 0.0001, respectively) compared with the baseline values, while plasma concentration of 8-hydroxy-2′-deoxyguanosine (8-OHdG) decreased significantly compared with soy milk (P < 0.05). In addition, a significant increase in superoxide dismutase (SOD) activity was observed in probiotic soy milk group compared with baseline value (P < 0.01). There were no significant changes from baseline in the promoter methylation of MSH2 within either group (P > 0.05). The consumption of probiotic soy milk improved antioxidant status in type II diabetic patients and may decrease promoter methylation among these patients, indicating that probiotic soy milk is a promising agent for diabetes management.