Association Between Dietary Flavonoids and Childhood Asthma

To further explore the relationship between childhood asthma and dietary flavonoids, which are plant-derived compounds found in many fruits and vegetables with anti-inflammatory, antioxidant, and immune-modulating properties. Despite substantial research on flavonoids’ health impacts, research focusing on childhood diseases has been limited.The study included 7913 participants younger than 20 years from the US National Health and Nutrition Examination Survey (NHANES) cycles 2007-2010 and 2017–2018. Of the 7913 children, 17% were diagnosed with asthma.Dietary intake over a 24-hour period was obtained via dietary interviews, from which study consumption of total flavonoids was calculated. The presence or absence of asthma was determined via a survey questionnaire. Multivariable logistic regression models were used to evaluate associations between flavonoid intake (as both continuous and categorical variables) and asthma prevalence, while adjusting for potential confounders. Stratified analyses were performed by sex, ethnicity, family smoking status, and income.Higher anthocyanin intake was significantly associated with lower asthma prevalence (odds ratio [OR] of 0.72). Median flavonol intake also was inversely associated with asthma prevalence compared with the lowest intake group (OR of 0.91). The stratified analyses additionally revealed a negative association between anthocyanin intake and asthma prevalence. This was pronounced in male individuals, non-Hispanic white individuals, nonsmoking families, and middle-income families. Significance based on age depended on the type of flavonoid assessed.Higher intake of dietary flavonoids, particularly anthocyanins and flavones, is correlated with lower asthma prevalence in children.This study is strengthened by its large sample size with adjustment for confounders and generalizability to US children and adolescents. However, its cross-sectional design precludes establishing causality, so it is not possible to determine whether increased flavonoid intake reduces risk or children with asthma may have differing dietary patterns for alternative reasons. Further, dietary recall via interviews can introduce recall and measurement bias, possibly leading to misclassification of consumption. Additionally, asthma has many confounding factors that cannot all be included in this study. Overall, although the findings support a potential protective role for flavonoid-rich foods in pediatric asthma, which is highly possible given the inflammatory nature of the disease, prospective and randomized studies would be required to confirm causality.