The causality between dietary intake and allergic diseases: A two-sample Mendelian randomization analysis

Summary

This two-sample Mendelian randomization study investigated causal relationships between 22 dietary factors and allergic diseases (asthma, atopic dermatitis, allergic rhinitis) using genetic instrumental variables to avoid confounding and reverse causality inherent in observational studies. Seven dietary factors showed protective effects against asthma and atopic dermatitis, including oily fish, dried fruit, cereal, fresh fruit, tea, and processed meat, with effect sizes ranging from OR 0.463 to 0.774. The findings suggest that diet may play a modifiable role in the prevention and management of allergic inflammatory conditions, though the mechanisms warrant further investigation.

Regional applicability

The study uses genetic data from population cohorts and does not specify geographic restriction, suggesting global applicability. UK clinicians and public health practitioners may consider these findings when advising patients on dietary modifications for allergic disease prevention, though dietary patterns and food availability differ by region and individual genetic susceptibility should be recognised.

Key measures

Odds ratios (OR) and 95% confidence intervals for associations between 22 dietary factors and three allergic disease outcomes; inverse-variance weighted, weighted median, and MR-Egger regression estimates; heterogeneity and pleiotropy assessment

Outcomes reported

The study identified seven dietary factors with causal associations to allergic diseases (asthma, atopic dermatitis, allergic rhinitis), including protective effects of oily fish, dried fruit, cereal, fresh fruit, tea, and processed meat against specific conditions. No significant causal relationships were observed for allergic rhinitis in the final analysis.

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