OBJECTIVE

To evaluate the association between dietary flavonoid intake and hypertension using nationally representative data, considering increasing global hypertension prevalence and inconsistent evidence on flavonoids' protective effects.

METHODS

This cross-sectional study analyzed 8,054 adults aged ≥20 years from NHANES 2007-2010 and 2017-2018. Flavonoid intake was assessed through two 24-hour dietary recalls and categorized into quartiles. Hypertension was defined by blood pressure ≥130/80 mmHg or self-reported diagnosis/medication use. Logistic regression models with progressive adjustment, restricted cubic spline regression for dose-response relationships, and subgroup analyses were conducted, accounting for complex sampling design.

RESULTS

After full adjustment, participants in the highest quartile of total flavonoid intake showed 25% lower odds of hypertension compared to the lowest quartile (OR = 0.75, 95% CI: 0.60-0.93,  = 0.01). Among flavonoid subclasses, anthocyanidins (OR = 0.74, 95% CI: 0.58-0.93) and flavan-3-ols (OR = 0.76, 95% CI: 0.62-0.93) demonstrated the strongest protective associations. Significant effect modifications were observed for age ( for interaction = 0.01), hyperlipidemia ( for interaction <0.0001), and cardiovascular disease status ( for interaction =0.01), with stronger protective effects in younger adults and those without metabolic disorders.

CONCLUSION

Moderate dietary flavonoid intake, particularly anthocyanidins and flavan-3-ols, is inversely associated with hypertension risk. These associations vary significantly by age and metabolic status, suggesting potential for individualized dietary recommendations for hypertension prevention.