News Medical this week features an “opinion leader” interview with Professor Sally Bloomfield. The full interview can be found at http://www.news-medical.net/news/20160811/Hygiene-hypothesis-a-misleading-misnomer-An-interview-with-Professor-Sally-Bloomfield.aspx
The interview explores why the term “hygiene hypothesis” is now being seen as a misleading and dangerous misnomer. The hygiene hypothesis, as first proposed in 1989, suggested that one of the causes of the rapid rise in childhood allergies is lack of exposure to childhood infections. Despite new knowledge suggesting that the exposures we need are not infectious microbes, continued use of the term “hygiene hypothesis” means that the link to hygiene, the idea that we have become too clean for our own good remains the most widely accepted explanation for the rise in allergies.
In 2003 Professor Rook proposed and alternative concept, the Old Friends mechanism, which offers a more rational explanation. He suggested that the exposures we need are the diverse range of mostly non harmful organism which we lived with during early hunter-gatherer times when our immune systems were developing. These exposures “teach” the immune system which microbes are harmful and need to be eliminated, and, equally important, which microbes and other exposures such as pollen etc are harmless and need to be tolerated. Without this Old Friends interaction, the immune system, can lose the ability to tolerate exposure to pollen, dust mites and foods and start to attack them causing allergic reactions. Research is showing that our reduced interaction with Old Friends is due to a whole range of lifestyle, medical and public health changes, and that, if home and personal cleanliness contributes, its contribution is likely to be small. Unfortunately, our new understanding of the underlying causes, based on the Old Friends mechanism, is still being called the “hygiene hypothesis”. As long as this occurs, the public misconception that children who are too clean and are not exposed to childhood infections are more likely to develop allergies will continue. This interview explores the answers to the following questions in more detail: · Why have we lost contact with the “Old Friends” microbes? · Is there evidence that hygiene is responsible for the loss of vital microbial exposures? · How can we tackle the rise of allergic diseases and what strategies could help us restore interaction with our old friends? · What further research is needed to evaluate how we can reverse trends in inflammatory diseases? · How can we protect ourselves against harmful microbes whilst at the same time restoring contact with our old friends? · What needs to be done to change public health and professional perceptions around hygiene? Where can readers find more information? · http://www.ifh-homehygiene.org/books/simple-guide-healthy-living-germy-world