Chlorine in treated drinking water


New member
Mar 23, 2024
Hi Michael,
I completed the follow up to my application a few months ago and just received your March 2024 applicant update email and decided to join this forum!

I have read much of your research and a few things have stuck out in my mind...

First I find it interesting that the good bugs in our bellies are passed down from our mothers through breast feeding. And I've also found it interesting how few donors are out there even the young healthy athletes you thought would be great candidates. I'm wondering how many potential applicants live in areas with city water in their homes? Most municipalities treat the water supply with chlorine and other disinfectants. Which in my mind would also kill the good bacteria in our guts. You mentioned the best donors are from indigenous peoples in South America and other remote regions. I wondered if you have tried locating applicants here in the USA from rural areas? For example, my entire family on both sides going back 5 generations have never lived in a home with city water. We also hunt wild game and grow alot of our own food. This is also true for most of my neighbors. I also live close to Amish communities who also have well water and make most of their own food, completely free of preservatives. They are also a group of people who use very little if any antibiotics for illnesses. Their lifestyle and diet would be very similar to native peoples in remote parts of the world.

Your research is suggesting that the good bacteria in our guts seem to be diminishing drastically and I wonder if a big culprit could be treated drinking water?
And is it possible country folks may be healthier than those who live in cities or suburban areas?

Not sure if this is helpful to you or not.


It's possible that chlorine is having some detrimental impact. Anecdotally, our 1-in-23,000 donor was drinking unfiltered tap water until I recommended they start using a filter. And one of the ideal donors I previously found lived in a home with an RO water system.

I found some mixed evidence:

Exposure to chlorinated drinking water alters the murine fecal microbiota (Jan 2024)

The Effects of Chlorinated Drinking Water on the Assembly of the Intestinal Microbiome (2019) - concept paper discusses the potential impact of chlorinated public drinking water on the assembly of the intestinal microbiome in infancy.

Drinking Water Source and Intake Are Associated with Distinct Gut Microbiota Signatures in US and UK Populations (2021) "No associations were found between oral microbiota composition and drinking water consumption"

Drinking Chlorinated Water in Low-Income Countries Passes Microbiome Test
the researchers found that children drinking chlorinated water had a significantly higher abundance of certain bacteria, with some populations more than twice as abundant as compared to the non-treated group. These included several bacteria linked to improved gut health. These differences, while minor, could be related to the 23% reduction in diarrhea and 7% reduction in antibiotic use found in the larger study.
There were also several antibiotic resistance genes that were found to be more abundant in children drinking chlorinated water. However, results of the bacteria analysis found that these genes were most likely a result of an increase in the presence of harmless strains of E. coli commonly found in mammals, which frequently harbor antibiotic resistance genes.
Overall, the researchers found that chlorination did not reduce the richness or diversity of bacteria species and had no negative impact on the children’s gut microbiome, supporting the use of chlorine in drinking water.

Regarding tribes, and other very-rural people in South America, etc. (including groups like the Amish), I cateloged some info here Overall I don't think they're promising candidates for FMT donors. As noted in one of the recent blogs, many of them are suffering from poor health themselves now. From what I've read, the Amish are not particularly healthy and suffer from health deficits related to poor genetic diversity.

Pollution is a major problem as well. Here's one example I saw covered in the news of mercury from gold mining poisoning South American tribal communities.

100 years ago rural people may have been better candidates and overall healthier, as Weston A. Price wrote about. But these days that doesn't seem to be the case anymore.

You mentioned the best donors are from indigenous peoples in South America and other remote regions.
Not exactly. They have the highest diversity, and that draws researchers to visit and study them, but I wouldn't call them "the best donors" or the best donor candidates. Someone who did FMT from one of Human Microbes' donors previously did FMT from multiple members of the Hadza tribe. From what I recall, they experienced significant temporary benefits but overall got worse due to the pathogens they picked up. They preferred my donors. They did describe some "super-human" traits of the Hadza though.

I wondered if you have tried locating applicants here in the USA from rural areas?
I have no way to specifically target them, but everyone is welcome to apply. If you're interested in trying to recruit you can email me about a referral reward.
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