What Does Tap Water Mean for Our Gut Bacteria? Dr Ruth Bowyer Explains in This Blog.

by Dr Ruth Bowyer

The global improvement to tap water quality worldwide has been a public health success, with access to clean water for drinking, food preparation and cleaning being essential for health. 

It’s understood that where there are contamination events – for example, pollutants entering water bodies that feed into tap water treatment works – drinking water can affect human health. How badly this might affect an individual might in part be due to their microbiome. 

Microbiome and health 

Whilst diet is frequently researched, drinking water, and its ability to alter gut bacteria, has been surprisingly overlooked. So that’s what we set out to do. 

We asked 90 of our amazing twins who have lived in the same house since they donated their microbiome samples to supply a much easier to acquire sample – tap water! We then looked for any associations between the tap water and the microbiota. 

Because drinking water in the UK is extremely regulated, we were not looking to see if there was a health effect of the water. Unless there are very old pipes, it is not only safe to drink but indeed essential to drink tap water regularly. 

What we found instead was that molecules that are commonly found in water (for example, minerals that are dissolved in the water), but differ from tap to tap and region to region, did associate with microbiome composition. 

This was a small, preliminary study, and further work and experiments are needed to confirm our findings, but it does suggest that tap water could influence the microbiome. 

This means that where there is a contamination event, one of the ways it might harm us is via the microbiome, and that in areas where this happens frequently, treatments targeted at the microbiome it might be one way of lessening its impact. 

Thank you to our twins 

We’d really like to thank the twins who participated in this project, who were extremely patient, engaged and a joy to speak to for the questionnaire part of the data collection. Every project is a constant reminder that all of the research we do would be impossible without our dedicated volunteers! 

Bowyer et al. Associations between UK tap water and gut microbiota composition suggest the gut microbiome as a potential mediator of health differences linked to water quality. Science of The Total Environment, 2020.