Summary:
Allergies are influenced not only by the immune system itself, but also by the microbes that live in the gut and the substances those microbes produce. Increasing attention has been given to the idea that changes in the gut microbiome may affect immune regulation across the body, including in conditions such as asthma, hay fever, and food allergy. In particular, researchers are interested in microbial metabolites, because these compounds may help shape inflammation, barrier function, and immune tolerance. This study is a review that examined how microbial metabolites may regulate allergic disease across different parts of the body. The study reviewed existing laboratory and clinical evidence on gut microbial imbalance and its effects on metabolite production. It focused especially on compounds such as short-chain fatty acids and other immune-active metabolites, which may help strengthen tissue barriers, reduce inflammatory responses, and influence how the immune system reacts to allergens. This study suggested that reduced microbial diversity and lower levels of beneficial metabolites may contribute to allergy development or severity, while approaches that improve gut microbial health, such as diet-based or microbiome-targeted interventions, may have therapeutic potential.
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Abstract:
Allergies are adverse immune responses to typically harmless substances, known as allergens. While allergies can involve diverse immune responses, type 2 immune responses that induce acute hypersensitivity mediated by mast cells, eosinophils and basophils are the major mechanisms underlying allergic disorders. Allergic diseases include atopic dermatitis, allergic rhinitis, food allergies and asthma. The onset and persistence of allergic disorders are influenced by genetic factors, pre-existing illnesses, age, environmental conditions and other lifestyle factors. In particular, diet and microbiomes considerably affect the incidence of various allergic diseases in the skin, lung and intestine. Individuals prone to develop allergic diseases often have impaired and skewed microbial diversification over the first year of life, and this can lead to altered levels of microbial metabolites in the intestine and inflamed tissues. Microbial metabolites, such as short-chain fatty acids, indole metabolites and bile acids, can exert specific regulatory effects on the various components of the immune system, such as barrier epithelial cells and immune cells, including dendritic cells, macrophages, T cells, B cells, innate lymphoid cells and mast cells. Microbial metabolites can also promote immune tolerance to allergenic substances by strengthening regulatory T cells. Understanding the role of these metabolites can lead to better prevention and control of allergic diseases. Here, in this review, we examine current research progress on the interactive relationship between microbial metabolites and allergic diseases and identify functionally important metabolites that affect allergic immune responses.
Article Publication Date: 18/02/2026
DOI: 10.1038/s12276-026-01642-1
