The farm effect revisited: from β-lactoglobulin with zinc in cowshed dust to its application

Abstract

Summary Background Numerous factors such as microbiota and their products are discussed in the context of the hygiene hypothesis and the associated allergy-preventive farm effect. Besides inhalation of dust from farms, consumption of raw milk also counteracts the development of asthma and allergies. Since cattle barns and cow’s milk in particular have been described as effective, the involvement of a bovine protein seems likely. β‑Lactoglobulin (BLG) is a major protein in milk and, as a member of the lipocalin family, has an intramolecular pocket that allows binding to hydrophobic ligands. Results Our in vitro and in vivo studies show that unloaded BLG promotes the development of allergy, while loaded, so-called holo-BLG, prevents allergies. BLG associated with zinc could also be detected in stable dust and ambient air of cattle farms. Conclusion It seems obvious that in addition to microbes and their products, holo-BLG also plays an important role in the protective farm effect. Therefore, in a newly developed lozenge for dietary management of allergies, based on the farm effect, zinc attached to holo-BLG is one of the key ingredients.