Association of niacin intake and metabolic dysfunction-associated steatotic liver disease: findings from National Health and Nutrition Examination Survey

Aim This study aims to explore the relationship between niacin intake and the prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) within a large, multi-ethnic cohort. Methods A total of 2946 participants from the National Health and Nutrition Examination Survey (NHANES) were carefully selected based on strict inclusion and exclusion criteria. Participants meeting the eligibility criteria underwent two dietary recall interviews, and niacin intake was calculated using the USDA's Food and Nutrient Database for Dietary Studies (FNDDS). Liver steatosis was diagnosed using a Controlled Attenuation Parameter (CAP) of 248 dB/m, and MASLD diagnosis was based on metabolic indicators. Weighted multivariate logistic regression was utilized to analyze the correlation between niacin intake and MASLD prevalence, with potential nonlinear relationships explored through restricted cubic spline (RCS) regression. Results Analysis of baseline data revealed that MASLD patients had lower niacin intake levels and poorer metabolic biomarker profiles. Both RCS analysis and multivariate logistic regression indicated a U-shaped association between niacin intake and MASLD prevalence. Specifically, there was a non-linear dose-response relationship, with the odds of MASLD gradually decreasing with increasing niacin intake until reaching a threshold of 23.6 mg, beyond which the odds of MASLD began to increase. Conclusion This study confirms a U-shaped nonlinear relationship between niacin intake and MASLD prevalence within the diverse American population.