July 27, 2017

expert reaction to comment article about modern lifestyle changes, gut microbial diversity, and chronic diseases

In a comment piece in Nature Reviews Immunology a researcher suggests that the rise in chronic diseases, such as asthma, obesity and inflammatory bowel disease, may be due to modern lifestyle changes that have reduced the microbial diversity in our gut.

Prof. Graham Rook, Emeritus Professor of Medical Microbiology, UCL, said:

“This is a succinct summary of the state of knowledge, and it will help the public and the media to avoid being misled by the term ‘hygiene hypothesis’ which is often applied to these concepts.  As is made clear in this article, hygiene is not to blame for the reduced microbial diversity in our guts.  The factors leading to this reduced diversity are well described, and hygiene is correctly not mentioned.  Hygiene is entirely beneficial except for the few behaviours that reduce transmission of the microbiota from mother and family to the child.”

Prof. Sally Bloomfield, Honorary Professor, London School of Hygiene and Tropical Medicine, and International Scientific Forum on Home Hygiene, said:

“This is an important article from a highly respected expert on this subject.

“In recent years our obsession with the so-called hygiene hypothesis and the idea that we have become ‘too clean for our own good’ has prevented us from understanding the true causes of the rise in chronic inflammatory diseases such as allergies.  The challenge now is to develop effective hygiene strategies which reduce infectious diseases and antibiotic prescribing, alongside lifestyle changes which restore diversity of the vital microbes which make up our microbiome.  This is possible – but first we must let go of the ‘hygiene hypothesis’ concept.”

Prof. Jonathan Ball, Professor of Molecular Virology, University of Nottingham, said:

“Many of us interested in the interplay between microbes and our immune system are starting to take more seriously the link between ‘clean living’ and health problems related to allergy-related chronic diseases, like asthma, but proving this link is extremely difficult.

“Anecdotally, we know that allergy is more rife in western populations and various studies have suggested this might be due to low exposure to bacteria, viruses and parasites.  We also know that the community of microbes that live upon and within us are also important for health.  They can help provide nutrition and protect from the invasion of more harmful infectious agents.  But how a lack of exposure to microbes or a shift in the composition of our microbiome might influence a large range of conditions is not clear to me.  I’m not saying there isn’t a link, but there needs to be a lot more proof and a lot more understanding before we can make any strong assertions.”

* ‘The theory of disappearing microbiota and the epidemics of chronic diseases’ by Martin J. Blaser published in Nature Reviews Immunology on Thursday 27 July 2017. 

Declared interests

None received.