Dietary-fibre intake, genetic factors, and the risk of nonalcoholic fatty liver disease: a prospective study in the UK Biobank

Nonalcoholic fatty liver disease (NAFLD) is a prevalent chronic liver condition with limited pharmacological treatments. Dietary fibre, known for its potential protective effects against NAFLD, may influence hepatic lipid metabolism through gut microbiota modulation and improved insulin sensitivity. However, the interaction between dietary fibre intake and genetic predisposition in NAFLD remains unclear. This study aimed to explore the association between dietary fibre intake and NAFLD risk, and whether genetic factors modulate this relationship. We conducted a prospective cohort study using data from the UK Biobank, including 424,008 participants without baseline liver disease. Dietary fibre intake was assessed using a validated food frequency questionnaire, and genetic risk was evaluated using a genetic risk score (GRS) for hepatic fat content. Cox proportional hazards models were used to estimate hazard ratios (HRs) for NAFLD risk, adjusting for covariates such as age, sex, BMI, and lifestyle factors. Over an average follow-up of 12.1 years, 4662 incident NAFLD cases were identified. Higher dietary fibre intake was inversely associated with NAFLD risk (HR for highest vs. lowest quintile: 0.70, 95% CI 0.61–0.80, p-trend < 0.001). Fibre from bread and cereals showed particularly strong inverse associations. Participants with high genetic risk had a higher NAFLD incidence (HR: 1.82, 95% CI 1.65–2.01), but higher fibre intake was associated with lower risk across all genetic risk groups. The combination of high genetic risk and low fibre intake resulted in the highest NAFLD incidence (HR: 2.85, 95% CI 2.20–3.70). Higher dietary fibre intake was associated with a reduced risk of NAFLD, and this inverse association was observed across all genetic risk groups. The findings suggest that increasing dietary fibre intake may benefit individuals regardless of their genetic predisposition, supporting dietary fibre intake could be a simple and effective strategy for NAFLD prevention.