Studies in recent years have demonstrated that the commensal intestinal flora (microbiome) plays a key role in the development of nonalcoholic steatohepatitis (NASH). An unfavourable microbiom can trigger disease development and progression. On the other hand, recent data show that modulation of the microbiom by a diet can prevent the developement of a NASH. Mechanisms of interaction between nutrition, microbiome, intestine and liver are largely unknown. In this research project, the effect of a fibre-rich oat bran on NASH will therefore be investigated. A better understanding of the interaction between diet, microbiome, intestine and liver could form the basis for new preventive therapies of NASH.

In recent years, the results of animal experiments and some human intervention studies indicate that the commensal intestinal flora (microbiome) plays a key role in the development of nonalcoholic steatohepatitis (NASH). An unfavourable composition of the microbiome can trigger disease development and progression. On the other hand, recent data show that modulation of the microbiome through diet, such as a high-fibre diet, can prevent the developement of a NASH. It has been shown that the uptake of fibre-rich oats reduces LDL and total cholesterol without altering the HDL cholesterol level. Indeed, the results of several human intervention studies suggest that a regular intake of oat flakes with prebiotic food supplements is sufficient to lower LDL and total cholesterol levels. In a small clinical trial it was also shown that an intake of oat bran with prebiotic food supplements in two servings per day was associated with a significant reduction in ALT and AST activity in the serum of overweight individuals with signs of altered liver function. In addition, the use of oat bran to influence postprandial glucose and insulin response and satiety was discussed.

However, the mechanisms underlying the positive effects of treatments with pro-, pre- or synbiotics are not yet fully understood and generally accepted therapeutic strategies are still lacking. The exact influence of a fibre-rich diet on intestinal microbiom and bile acid composition is not yet known. In the research project described, the effect of oat bran with prebiotic food supplements on NASH will be investigated and mechanisms of interaction between diet, microbiome, bile acids and liver will be uncovered. A better understanding of this interaction could form the basis for new preventive therapies of NASH.

Inclusion Criteria:

• Fatty liver disease diagnosed by sonography (steatosis hepatis grade II and III) and CAP measurement (> 280dB)
• compliance

Exclusion Criteria:

• Allergy to oats
• Alcohol intake of more than 30 g/d (men) or 20 g/d (women)
• Treatment with ursodeoxycholic acid (UDCA), vitamin E or other NASH drugs 3 months prior to randomization
• Hepatocellular carcinoma or non-hepatic malignancy within the last 5 years
• Evidence of cirrhosis of the liver (Child A, B, C) or a history of decompensation
• Liver diseases not related to NASH, including chronic viral hepatitis B/D or C, autoimmune hepatitis, Wilson's disease or clinically manifest iron overload (heterozygous HFE is permitted), cholestatic liver disease (PBC/PSC)
• Adiposity surgery in the last 5 years
• BMI <18.5 kg / m2
• Liver transplantation
• Fibroscan> 12 kPa (patients with liver cirrhosis)
• Lack of CAP and ultrasound evaluation
• Age > 75 years
• HIV infection
• Heart Failure (New York Heart Association Class III - IV)
• Myocardial infarction, unstable coronary artery disease, coronary artery intervention or stroke in the last 6 months
• Unstable COPD, chronic inflammatory bowel disease or rheumatoid arthritis
• Unstable renal failure (changes in serum creatinine > 50% in the last 3 months) or terminal renal failure requiring dialysis
• Uncontrolled hypertension (SBP / DBP> 180/90 despite therapy)
• Uncontrolled metabolic conditions (poorly controlled or decompensated diabetes mellitus, HbA1c >7.5%)
• Food allergies or intolerances that require strict adherence to a diet, such as lactose intolerance or celiac disease.
• Pregnancy or breastfeeding women (anamnesis)
• Treatment with drugs or substances that can induce secondary NASH (e.g., tamoxifen, corticosteroids, amiodarone, methotrexate) or alleviate NASH (TNF antagonists) (e.g. metformin)
• Use of herbal food supplements
• Any participant who has taken antibiotics 6 weeks prior to the study