The effect of daily consumption of probiotic yogurt on liver enzymes, steatosis and fibrosis in patients with nonalcoholic fatty liver disease (NAFLD): study protocol for a randomized clinical trial

BACKGROUND: Given the increasing prevalence of non-alcoholic fatty liver disease, it is necessary to find an easy and cost-effective method in its management and treatment. Probiotics are a group of living microorganisms that might affect NAFLD through the intestinal-liver axis. The present clinical trial aims to examine the effect of probiotic yogurt consumption on liver enzymes, steatosis and liver fibrosis in patients with NAFLD. METHODS: Sixty-eight patients with NAFLD will be recruited in this study. After block matching for sex, BMI and age, patients will be randomly assigned to receive 300 g/d probiotic yogurt containing 10(6) cfu/g of Lactobacillus acidophilus and Bifidobacterium lactis strains or 300 g/d plain yogurt daily for 12 weeks and those in the control group would receive similar amounts of plain yogurts. Weight, height, and waist circumference will be measured at study baseline and after the intervention. Biochemical indicators including plasma glucose, serum insulin, lipid profile, liver markers (ALT, AST and GGT) will be examined at study baseline and at the end of the trial. Insulin resistance and insulin sensitivity will be determined using the HOMA-IR and QUICKI equation. The degree of steatosis and hepatic fibrosis will also be assessed at the beginning and end of the intervention by the same gastroenterologist using elastography with fibroscan. DISCUSSION: Probiotics have been suggested as a new strategy in the management of NAFLD. Their effects might be mediated through intestinal microbiota modification and production of short-chain fatty acids. Consumption of probiotic-enriched foods, rather than their supplements, might be a cost-effective method for long-term use in these patients. In case of finding the beneficial effects of probiotic yogurt consumption in the current clinical trial, its inclusion in the dietary plan of NAFLD patients can be recommended. Trial registration This clinical trial was registered in Iranian Registry of Clinical Trials (www.irct.ir) at 2021-04-19 with code number of IRCT20210201050210N1.