What is the hygiene hypothesis?

The hygiene hypothesis posits that exposure to a diverse range of pathogens, particularly early in life, is essential for the proper development of the immune system. This theory suggests that a lack of exposure to microorganisms—due to improved sanitation and hygiene practices—can lead to an increase in allergic diseases and autoimmune disorders. The idea is that our immune system needs to train and learn to differentiate between harmful and benign entities, and without regular exposure to various pathogens, it may become unbalanced, leading to inappropriate immune responses.

The hygiene hypothesis emphasizes the importance of natural exposure to microbes for educating the immune system. This contrasts with ideas that focus solely on vaccination or that attribute immune issues solely to genetic factors. It suggests a more holistic view of health, where environmental interactions play a vital role in immune development.