The mediating role of C-reactive protein (CRP) in the dietary intake of flavonoids and the risk of albuminuria†

Abstract

Background: Prior experimental investigations have highlighted the beneficial effects of flavonoid consumption on renal function. However, a comprehensive evaluation of their impact on modulating albuminuria risk within population-based epidemiological studies is still limited. This study aimed to fill this gap by examining the correlation between flavonoid intake and albuminuria risk, while also shedding light on the potential mediating influence of inflammation in this association. Methods: We utilized data from 29 940 participants spanning three cycles (2007–2008, 2009–2010, and 2017–2018) of the National Health and Nutrition Examination Survey (NHANES). We employed rigorous analytical methods, encompassing logistic regression, restricted cubic splines (RCS), and mediation analysis, to assess the link between dietary flavonoid intake and albuminuria risk. Results: Our findings reveal consistent negative associations between total flavonoids and specific subclasses, including flavonols, flavones, flavan-3-ols, anthocyanidins, and catechins, and the risk of albuminuria. Specifically, after adjusting for confounding factors, each logarithmic unit increase in these flavonoid categories was associated with a decrease in albuminuria risk ranging from 3% to 12%. The mediating proportion of C-reactive protein (CRP) in the relationships between the intake of total flavonoids, flavonols, flavones, catechins, and flavan-3-ols and albuminuria risk was 7.3%, 5.6%, 2.3%, 7.7%, and 4.6%, respectively. Conclusions: These results indicate that increased consumption of flavonoid-rich foods contributes to a reduced risk of albuminuria.