Water: a source of life for the microbiota?

Diet

“Beware of still waters”, as say the French. Does it matter where the water we drink comes from? Scientists argue that the source of our water (bottled, tap, filtered, or well water) and the quantity we drink do have an impact on the composition of our gut microbiota.

About this article

Created 14 March 2022

Updated 27 May 2022

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.

This is no longer the case. It now appears that water plays a major role in the composition of our gut microbiota, which is watered daily by two liters of liquid. This is what a team of researchers¹ found when they looked at data from a previous study on British² and American³ subjects.

United States

2.7 L/d for women
3.7 L/d for men
of which 70%-80% comes from beverages and the remainder from food.

Europe

2.0 L/d for women
2.5 L/d for men
of which 80% comes from beverages and the remainder from food.

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.

The gut microbiota

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... 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!

Sources

^{1. Vanhaecke T, Bretin O, Poirel M et al. Drinking Water Source and Intake Are Associated with Distinct Gut Microbiota Signatures in US and UK Populations. J Nutr. 2022 Jan 11;152(1):171-182.}

^{2. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA). Scientific opinion on dietary reference values for water. EFSA J 2010;8(3):1459}

^{3. Institute of Medicine. Dietary Reference Intakes for water, potassium, sodium, chloride, and sulfate. Washington (DC): National Academies Press; 2005}