Associations Between Polyphenol Intake, Cardiometabolic Risk Factors and Metabolic Syndrome in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Background: Fruit- and vegetable-rich diets may protect against metabolic syndrome (MetS), partly due to their high polyphenol content. Objectives: This study examined the association between dietary polyphenol intake, MetS risk, and cardiometabolic factors in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Methods: A total of 6387 participants (mean age 49.8 y, 65% female) were included. Food intake was assessed via a semiquantitative Food Frequency Questionnaire with polyphenol content from the Phenol-Explorer database. MetS was defined using the Joint Interim Statement. Logistic regressions assessed associations between polyphenol intake tertiles and cardiometabolic risk factors, as well as the odds of MetS during the follow-up period. Results: During a median of 8.19 y follow-up, 2031 cases of MetS occurred. The second and third tertiles of total polyphenol intake were associated with 22% and 23% lower odds of MetS, respectively, after adjusting for sociodemographic, lifestyle, and dietary factors (T2 vs. T1, odds ratio [OR] 0.78 [95% confidence interval {CI}: 0.68, 0.90]; T3 vs. T1, OR 0.77 [0.66, 0.90]). Inverse associations were also found between phenolic acids, lignans, stilbenes, other polyphenols, and the odds of MetS. Although no significant link was observed for total flavonoids, flavan-3-ols showed inverse associations with MetS (monomers: T3 vs. T1, OR 0.92 [0.80, 0.94]; dimers to polymers: T3 vs. T1, OR 0.82 [0.70, 0.96]). Total polyphenol intake was also inversely associated with waist-hip ratio, diastolic blood pressure, systolic blood pressure, HOMA-IR, triglycerides, and C-reactive protein, and positively associated with total cholesterol, LDL cholesterol, and HDL cholesterol. Conclusions: Higher intakes of dietary polyphenols, particularly phenolic acids, lignans, stilbenes, other polyphenols, and flavan-3-ols, were inversely associated with the odds of MetS and its components. These findings suggest that promoting polyphenol-rich diets could be a valuable strategy in reducing cardiometabolic risk and preventing MetS in the population, potentially informing dietary guidelines and public health interventions.