Association between dietary flavonoids and childhood asthma.

Objective: Dietary flavonoids in various green plants have anti-inflammatory, antioxidant, and immune-modulating properties. While numerous studies have confirmed that flavonoid substances benefit asthma, evidence remains limited in epidemiological research and human experiments. This study aimed to explore the relationship between childhood asthma and dietary flavonoids.

Methods: Dietary flavonoids comprise isoflavones, anthocyanins, flavan-3-ols, flavanones, flavones, and flavonols. This study used data from the United States National Health and Nutrition Examination Survey, collected during interviews from 2007 to 2010 and 2017 to 2018. Asthma data were obtained from the survey questionnaire. The analysis included 7,913 participants under 20 years old. A multivariable logistic regression model was performed to investigate the correlation between flavonoids (as constant or category variables) and asthma frequency among children in the United States, with stratified analyses performed for each group.

Results: After adjusting for potential confounding variables, a significant negative correlation was observed between asthma incidence and the highest intake group of anthocyanins compared to the lowest intake group (odds ratio [OR] = 0.83, 95% confidence interval [CI]: 0.72-0.97, and p = 0.0182). Similarly, asthma incidence indicated a significant negative association with the median flavonol intake group compared to the lowest intake group (OR = 0.83, 95% CI: 0.72-0.97, and p = 0.0165). In the stratified analysis, anthocyanin content demonstrated a significant negative correlation with asthma prevalence among males, non-Hispanic whites, nonsmoking families, and middle-income families (p < 0.05).

Conclusion: The intake of dietary flavonoids, including anthocyanins and flavonols, is correlated with asthma prevalence in children.