on June 16, 2026
When the immune system overreacts
Allergic diseases are among the most common immunological conditions worldwide. Allergic rhinitis, asthma, urticaria, atopic dermatitis, and eczema share a common element: an excessive immune response to substances that are normally harmless.
Pollen, dust, mites, animal hair, and certain occupational or environmental substances are recognized as threats by the immune system, which activates an inflammatory response aimed at eliminating them.
The result, however, is a disproportionate reaction that generates symptoms that are often persistent and sometimes disabling.
The discovery of IgE: a breakthrough in the understanding of allergies
The modern understanding of allergies changed radically in the 1960s thanks to the work of Kimishige Ishizaka in the United States and Gunnar Johansson and Hans Bennich in Sweden.
The researchers identified a new class of antibodies: immunoglobulin E (IgE).
Today, IgE represents the main immunological mechanism involved in immediate allergic reactions.
When a predisposed person comes into contact with an allergen, the immune system produces specific IgE that binds to cells called mast cells and basophils.
Upon subsequent contact with the same allergen, rapid cellular activation occurs, releasing inflammatory mediators.
Among these, the best known is histamine.
The role of histamine: why inflammation is triggered
Histamine is a biologically active molecule stored mainly in mast cells.
Once released, it causes:
vasodilation
increased vascular permeability
mucosal congestion
itching
mucus production
bronchoconstriction
These mechanisms explain the typical symptoms of allergies such as sneezing, nasal congestion, red eyes, cough, difficulty breathing, and skin manifestations.
Alongside histamine, other inflammatory mediators such as leukotrienes, prostaglandins, and Platelet Activating Factor (PAF) are involved, which further amplify the allergic response.
Allergies and the gut: the role of the biological terrain
In recent years, it has become understood that the intestinal immune system plays a central role in regulating allergic responses.
In fact, about 70% of the body's immune cells are associated with the gut.
Alterations in the gut microbiota, increased intestinal permeability, and reduced immunological tolerance can promote a state of hyperreactivity.
For this reason, rebalancing the biological terrain represents an increasingly studied component in the management of allergic conditions.
Among the support strategies, there are:
a varied diet rich in fresh foods
an initial reduction of histamine-rich foods in sensitive individuals
attention to intestinal function
adequate intake of fermentable fibers
support of the microbiota through selected ferments when indicated
increased intake of polyunsaturated fatty acids.
Nutrients and natural substances studied in the modulation of the allergic response
Ginkgo biloba
Ginkgo biloba extracts have been studied for their ability to modulate inflammatory mediators and reduce the activity of Platelet Activating Factor (PAF).
This action could contribute to limiting some of the processes involved in the allergic response and bronchoconstriction.
Clinical evidence remains limited, but the biological mechanisms are of interest.
Plantain (Plantago spp.)
Plantain contains iridoid glucosides and polyphenolic compounds with anti-inflammatory properties and an activity that modulates the irritative response of the mucous membranes.
Traditionally, it is used as support for respiratory conditions and irritative manifestations.
Oat and avenanthramides
Oats contain avenanthramides, unique polyphenols studied for their anti-irritant activity.
Numerous experimental studies show the ability of avenanthramides to reduce the activation of the nuclear factor NF-κB and decrease the release of pro-inflammatory cytokines.
Anti-pruritic properties have also been observed, which are useful especially in dermatology.
Purified Aloe
Purified aloe gel has been studied for supporting skin hydration, maintaining barrier function, and modulating some local inflammatory processes.
Topical use is employed especially in conditions characterized by irritation and skin discomfort.
Perilla frutescens: one of the most studied plants in the support of allergies
Among the most interesting natural substances is Perilla frutescens.
The seeds and leaves are rich in alpha-linolenic acid (ALA), polyphenols, and phytosterols.
Several experimental studies suggest that Perilla can:
modulate histamine release
reduce leukotriene synthesis
influence IgE production
contribute to the control of the inflammatory response
These mechanisms have generated interest especially in the support of seasonal allergies, atopic dermatitis, and respiratory conditions characterized by hyperreactivity.
However, the available clinical evidence is still limited and does not replace validated medical treatments.
Diet and lifestyle: the first intervention
In allergic conditions, the first intervention remains the improvement of the general biological context.
A diet rich in plant-based foods, fiber, and unsaturated fats, combined with regular sleep, physical activity, and stress reduction, contributes to the regulation of immune responses and the reduction of the chronic inflammatory state.
The goal is not to suppress the immune system but to promote a more balanced and tolerant response.
Conclusions
Allergies are not simply a reaction to an external allergen but represent the result of a complex interaction between genetic predisposition, the immune system, the intestinal barrier, and the environment.
The discovery of IgE revolutionized the understanding of allergic mechanisms, while the most recent research is highlighting the central role of inflammation and the microbiota.
Alongside conventional therapies, diet, lifestyle, and certain natural compounds can represent support tools within an integrated and personalized approach.
Bibliography
Ishizaka K, Ishizaka T. Identification of gamma-E-antibodies as a carrier of reaginic activity. J Immunol. 1967.
Johansson SGO, Bennich H. Immunological studies of an atypical myeloma immunoglobulin. Immunology. 1967.
Galli SJ, Tsai M. IgE and mast cells in allergic disease. Nature Medicine. 2012.
Akdis CA, Agache I. Global Atlas of Allergy. European Academy of Allergy and Clinical Immunology. 2014.
Platts-Mills TAE. The allergy epidemics. J Allergy Clin Immunol. 2015.
Sur R et al. Oat avenanthramides reduce inflammation and itch. Arch Dermatol Res. 2008.
Yamamoto H et al. Anti-allergic effects of Perilla frutescens extracts. Bioscience Biotechnology and Biochemistry. 2004.
Kim HM et al. Inhibitory effect of Perilla extract on allergic inflammatory responses. International Immunopharmacology. 2011.
Singh B et al. Biological activities of Aloe vera. Journal of Ethnopharmacology. 2013.
Diamond BJ et al. Ginkgo biloba mechanisms and clinical applications. CNS Drug Reviews. 2000.
