Evaluating the relationship between dietary flavonoids intake and constipation incidence in the general US population

Dietary adjustment has consistently been regarded as an effective and health way for both the prevention and treatment of constipation. Several researches suggest a significant correlation between dietary flavonoids intake and gut microbiota, while the relationship between dietary flavonoids and constipation has not been reported. The objective of this study is to investigate the relationship between flavonoids intake and constipation.

This cross-sectional analysis was based on data from the National Health and Nutrition Examination Survey (NHANES) collected from 2007 to 2010. The dietary flavonoid and subclasses intake value were obtained from the United States Department of Food and Nutrient Database for Dietary Studies (FNDDS), while constipation was defined using the stool consistency or frequency. Relationships between total and six main flavonoid subclasses intake constipation were investigated using weighted logistic regression approach.

The study revealed a negative association between isoflavones, anthocyanidins, flavanones, flavones, flavonols, and total flavonoid intake and constipation, with significant p-trends of < 0.05. Following multivariate adjustment, decreased odds of constipation could still be observed in the highest quartiles of anthocyanidins compared with those in the reference quartiles (p-value = 0.03). Ln-transformed anthocyanidins exhibited a statistically significant nonlinear association with constipation, displaying an inverted U-shaped pattern. When anthocyanidins intake exceeded 0.92 mg, the rate of constipation trended downward with increases in anthocyanidins intake.

Our study demonstrated that higher dietary flavonoids intake can reduce the incidence of constipation in the adult US population. In addition, the negative association between anthocyanin intake and constipation was more stable compared to other subclasses.