Substantial evidence that alterations in the gut microbiome early in life “imprint” gut mucosal immunity, which is probably important for development of food allergy.
Maternal factors, timing and how solids introduced all likely to be important.
Experimental studies have shown that faecal transplants or other attempts to modify bacterial commenals can prevent or treat food allergy.
Mechanisms include restoration of gut immune regulatory checkpoints (eg retinoic orphan receptor gamma T+ regulatory T cells), the epithelial barrier, and healthy immunoglobulin A responses to gut commensals.
[Rima Rachid, JACI 2021]