Background: Emerging evidence suggests that animal protein foods may increase the risk of nonalcoholic fatty liver disease (NAFLD). We therefore examined the NAFLD risk reduction related to substituting plant protein foods for animal protein foods.
Methods: The cohort in North China included 14,541 participants from the Tianjin Chronic Low-Grade Systemic Inflammation and Health (TCLSIH) study, and the cohort in South China included 1297 participants from the Guangzhou Nutrition and Health Study (GNHS). Dietary intake was assessed using validated food frequency questionnaires. NAFLD was ascertained by abdominal ultrasound. The Cox model was used to fit the substitution analysis.
Results: In the TCLSIH cohort, when replacing one type of animal protein food (eggs, processed meat, unprocessed red meat, poultry, and fish) with an equivalent serving of plant protein foods (nuts, legumes, and whole grains), the replacement of animal protein foods with whole grains showed the strongest benefit; substituting one serving per day of whole grains for an equal amount of eggs (hazard ratio [HR] = 0.89; 95% confidence interval [CI]: 0.79, 1.00), processed meat (HR = 0.76; 95% CI: 0.64, 0.91), unprocessed red meat (HR = 0.90; 95% CI: 0.81, 1.00), poultry (HR = 0.81; 95% CI: 0.72, 0.92), or fish (HR = 0.87; 95% CI: 0.78, 0.97) was associated with a lower risk of NAFLD. In both the TCLSIH and GNHS cohorts, replacing poultry with fish, nuts, legumes, or whole grains was associated with a lower risk of NAFLD. When different numbers of protein foods were simultaneously replaced, the risk reduction of NAFLD was stronger.
Conclusions: Our findings suggest that replacing animal protein foods with plant protein foods is related to a significant reduction in NAFLD risk.
Keywords: NAFLD; cohort study; fatty liver disease; food; protein; substitution analysis.