The Farm effect: Cow's milk protein Beta-lactoglobulin prevents allergies

Published: May 29, 2020

Numerous studies demonstrate that the combination of growing up on a farm and drinking unprocessed cow milk during childhood protects against the development of immunoglobulin E (IgE) antibodies, which are responsible for allergic symptoms.

The farm environment trains the immune system; children who play on the farm and drink unprocessed milk suffer less frequently from allergies and asthma. This effect is referred to as the protective farm effect.

In a study recently published in The Journal of Allergy and Clinical Immunology (JACI), the research team led by Franziska Roth-Walter and Erika Jensen-Jarolim explores the evolution of this protective farm effect.

The authors determined that the protective farm effect can be attributed to the cow protein, beta-lactoglobulin, which is identified as a critical molecule in preventing allergies and also constitutes half of the whey proteins present in farm milk.

The authors demonstrated that when beta-lactoglobulin binds certain ligands, such as plant pigments from forage (e.g. iron-quercetin), it non-allergenic. In contrast, when the beta-lactoglobulin pocket is empty of ligands, it is allergenic.

The allergy-protective role of beta-lactoglobulin can be explained by the fact that this protein shuttles ligands with anti-inflammatory properties directly to immune cells and initiates there tolerogenic, anti-inflammatory pathways. Ligands also prevent IgE binding, suggesting again that milk-allergic children are sensitized to the empty, ligand-free form of beta-lactoglobulin protein, and that the ligand-filled form is protective.

The study identifies beta-lactoglobulin together with its ligands as essential for the allergy protective farm effect. Circumstances that lead to a loss or a deficiency in these ligands, e.g. due to industrial milk processing or poor forage quality, can abolish the tolerogenic impact of the cow protein beta-lactoglobulin and transform it into an allergen.

The work was supported by the Austrian Science Fund FWF.

The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.

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