Nour Makarem, Yasmin Mossavar-Rahmani, Daniela Sotres-Alvarez, Simin Hua, William W Wong, Linda Van Horn, Martha L Daviglus, Adrian A Franke, Marc D Gellman, Robert C Kaplan, Jeannette M Beasley

Background: Polyphenols offer high antioxidant potential that may protect against chronic diseases. Epidemiologic evidence documenting their influence on body composition and obesity risk is limited, particularly among Hispanics/Latinos who are disproportionately prone to obesity. Objectives: The aims of this study were to evaluate cross-sectional associations of urinary polyphenols with body mass index (BMI) and body fat percentage (%BF) in a diverse Hispanic/Latino population and to assess the reliability of polyphenol measurements. Methods: Participants were 442 adults from the Study of Latinos/Nutrition and Physical Activity Assessment Study (SOLNAS) aged 18-74 y. Doubly labeled water was used as an objective recovery biomarker of energy. Polyphenol excretion from 24-h urine samples was assessed. Measures were repeated in a subsample (n = 90) to provide a reliability measure. Anthropometric measures were obtained by trained personnel, and %BF was measured by 18O dilution. Linear regression models were used to evaluate multivariable associations between body composition and polyphenols. Spearman correlation coefficients between BMI and %BF with polyphenols and intraclass correlation coefficients (ICCs) between polyphenol measures were computed. Results: A weak correlation was observed for resveratrol and %BF (r = -0.11, P = 0.02). In multivariable-adjusted regression models, weak inverse associations were observed for resveratrol and urolithin A with %BF [β ± SE: -0.010 ± 0.004 (P = 0.007) and -0.004 ± 0.002 (P = 0.03), respectively]. For every 50% increase in these urinary polyphenols, there was a 1% and 0.4% decrease in %BF. Urolithin A was inversely associated with BMI (β ± SE: -0.004 ± 0.002; P = 0.02) and with 5% lower odds of obesity in models not adjusted for total energy expenditure (TEE; OR: 0.95; 95% CI: 0.91, 0.99; P = 0.02). For every 50% increase in urolithin A, there was a 0.4-unit decrease in BMI. Associations were attenuated after adjustment for TEE. Reliability study findings were indicative of weak to moderate correlations (ICCs: 0.11-0.65), representing a degree of within-person variation in polyphenol biomarkers. Conclusions: Although associations were weak, resveratrol and urolithin A were inversely associated with obesity. Repeated polyphenol urine measures could clarify their long-term impact on body adiposity.