The Hygiene Hypothesis – Learning From but Not Living in the Past
The epidemiological basis for the Hygiene Hypothesis became apparent long before the Hygiene Hypothesis was postulated.
Postulated by Strachan more than 30 years ago, the Hygiene Hypothesis has undergone many revisions and adaptations. This review journeys back to the beginnings of the Hygiene Hypothesis and describes the most important landmarks in its development considering the many aspects that have refined and generalized the Hygiene Hypothesis over time. From an epidemiological perspective, the Hygiene Hypothesis advanced to a comprehensive concept expanding beyond the initial focus on allergies. The Hygiene Hypothesis comprise immunological, microbiological and evolutionary aspects. Thus, the original postulate developed into a holistic model that explains the impact of post-modern life-style on humans, who initially evolved in close proximity to a more natural environment. Focusing on diet and the microbiome as the most prominent exogenous influences we describe these discrepancies and the resulting health outcomes and point to potential solutions to reestablish the immunological homeostasis that frequently have been lost in people living in developed societies.
Last year we celebrated the 30th anniversary of the Hygiene Hypothesis. Since Strachan framed the Hygiene Hypothesis in 1989 his fundamental idea to explain the origins of allergic diseases development has survived the test of time. The basic idea of how humans, their microbiota, and a continuously modernizing environment have interacted to drive immune dysregulation has persisted and become part of the popular imagination. Here, we aim to provide an editorial overview on the history of the Hygiene Hypothesis and related topics to offer a framework for the articles collected in the special edition research topic “The Hygiene Hypothesis and its Immunological Implications.”
