Background Animal studies have shown that soy protein and isoflavones can increase antioxidant capacity and improve insulin resistance, and thus ameliorate nonalcoholic fatty liver disease (NAFLD). However, only limited epidemiological studies have examined the association of soy food intake with NAFLD. Objectives We investigated the association between soy food intake and NAFLD in a Chinese cohort. Methods A total of 24,622 participants aged 20–90 y were included in the study. Diet information

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... was collected using a validated 100-item FFQ. NAFLD was defined as having fatty liver diagnosed by ultrasonography and excluding men and women who consumed >210 g alcohol/wk and >140 g/wk, respectively. Logistic regression analysis was used to assess the association of soy food intake with NAFLD. Results After adjustment for potential confounders, and taking those with <1 time/wk soy food intake as the reference group, the ORs for NAFLD across soy food intake frequency were 0.94 (95% CI: 0.83, 1.07) for 1 time/wk, 0.88 (95% CI: 0.78, 0.99) for 2–3 times/wk, and 0.75 (95% CI: 0.65, 0.87) for ≥4 times/wk (P-trend <0.0001). The results were similar when participants were categorized by the energy-adjusted soy food intake (grams per 1000 kilocalories) quartiles (OR = 0.80; 95% CI: 0.71, 0.91; comparing extreme quartiles). Conclusions Higher soy food intake was associated with a lower prevalence of NAFLD in Chinese adults. Further prospective studies and randomized clinical trials are necessary to confirm if soy food intake is inversely related to the risk of NAFLD.