Tap water vs filtered water: Does it make a difference in your gut?

Tap water vs. filtered water, does it really make a difference in your gut? Gut microbiomes are the little ecosystems of bacteria that our bodies host. They even outnumber our own cells. Unlike us, they are constantly working, all day and all night. The gut microbiome is an incredibly complex system, vital to our health. When we drink water, it travels to our intestines, where it is absorbed and circulated throughout the body. But does it matter what type of water we drink?

What is water filtration?

Water filtration is the process of removing and limiting impurities from drinking water. Drinking water in the United States is among the safest, but most communities in the country still use water treatment processes to filter and disinfect water. These processes vary among municipalities. They often include a variety of filtration technologies and the addition of disinfectants and public health additives like chlorine and fluoride.

Home water filters are an extension of this filtration process. Though there is a plethora of models on the market, the most common are water filter pitchers, refrigerator filters, faucet-mounted filters, built-in filters, under-sink filters, and whole-house treatment units. Each works in its own way and has a different degree of filtration.

How does a filter change what comes out of my tap?

Zooming in, let's talk about what exactly changes when tap water is run through one of the most common home water filters: the water filter pitcher. While most water filter pitchers use a combination of filtration technologies, one key player is called activated carbon filtration. This filtration system absorbs contaminants that can contribute to water taste and odor like a sponge, and some designs remove chlorination byproducts, cleaning solvents, and pesticides that can be present in tap water.

Does it make a difference in your gut?

You may now be wondering, what does this all mean for your microbiome? Can drinking different types of water have a different effect on your gut? A few scientific research studies with animal models say that it may. They've narrowed down on one key trait of municipal tap water: chlorination. Chlorine is added in the water treatment process to disinfect the water and eliminate parasites, bacteria, and viruses. This process is tightly regulated, and harmful health consequences are unlikely to occur from water chlorination.

However, prolonged consumption of chlorinated water (most tap water in the United States) has been linked to disruptions to microbial diversity in the mouse microbiome. This may be associated with the effects of chlorine itself, its disinfection by-products, or the observed increased bacterial exposure from home water filters.

On top of this, a study in healthy twin infants found a connection between domestic water sources and their microbial signatures. However, other current research on drinking water as a determinant for the human gut microbiome is limited. Regardless, the next time you reach for your water filter pitcher, you can thank it for keeping your gut microbiome in tip-top shape.

If you'd like to see what's under the hood in your microbiome, find out with Floré.