Water: a source of life for the microbiota?

Bottled, tap, filtered, or well water: not all water is the same when it comes to origin (groundwater, surface water, etc.), treatment (filtration, disinfection, etc.), and therefore chemical, mineral, or microbial composition. Despite being consumed in far greater quantities than food, water is often overlooked when it comes to scientific studies on diet and the microbiota. The effects of certain foods (dark chocolate, avocado, tea, etc.) and beverages (soda, alcohol, beet juice, etc.) have been studied carefully, but scientists have been reluctant to look at the role played by water.

A qualitative effect...

The results? The source of our drinking water is a key factor behind variations in the composition of the gut microbiota. Its influence is comparable to that of alcohol consumption or diet. Each type of water consumed corresponds to a different gut microbiota signature. Do you mainly drink well water? Your gut microbiota is likely to be more diverse than if you drink tap, filtered, or bottled water. Moreover, your digestive tract probably hosts more bacteria from the genus Dorea and fewer Bacteroides, Odoribacter and Streptococcus. What’s behind the difference? It may be because well water has greater microbial diversity than tap water due to the lack of systematic disinfection.

... and a quantitative effect

But it’s not all about where our water comes from. Quantity also plays a role. The gut microbiota of low water drinkers (from all sources) differs from that of high water drinkers. For example, low water drinkers have a greater abundance of Campylobacter, a bacterium associated with gut infections. This should encourage us to lift our glass more... provided we’re only drinking water!