A data-driven principal component analysis of age-3 food-frequency questionnaires from the Vitamin D Antenatal Asthma Reduction Trial identified a processed-meat/fried-food dietary pattern (PC3) as the strongest predictor of concurrent asthma/wheeze, with an odds ratio of 1.42 per 1-SD increase (P = 0.00109) in 791 children. That association held prospectively at age 6, and an independent NHANES 2021–2023 cohort of children aged 2–3 years showed a directionally consistent OR of 1.59 (95% CI 0.95–2.67). PC3 scores also correlated with gut microbiome composition and stool/plasma metabolites spanning steroid sulfates, vitamin E-related compounds, nucleosides, and lipids.
This preprint — not yet peer-reviewed — advances the asthma-diet field in a meaningful way by moving beyond single-nutrient associations to co-consumption patterns, which better reflect real eating behavior. The mechanistic thread connecting fried/processed-meat intake to steroid-sulfate and lipid metabolite shifts is biologically plausible: oxidized lipids and advanced glycation end-products in fried foods can promote airway inflammation via prostaglandin and leukotriene pathways. However, key limitations temper enthusiasm: the NHANES confidence interval crosses 1.0, sample sizes are modest, dietary recall methods introduce measurement error, and residual confounding (household smoke, socioeconomic status) cannot be excluded in an observational design. Still, the prospective design and multi-cohort replication elevate this above purely descriptive work. For parents and clinicians, the signal reinforces existing guidance to limit ultra-processed foods in toddlers — though causal claims must await peer review and ideally a randomized dietary intervention.
