The evidence and rationale supporting our stool donor criteria
In this blog post, I’ll address common questions about our stool donor criteria. Namely, why we focus so much on top young athletes.
Where are Human Microbes’ super-donor criteria coming from?
Human Microbes’ stool donor criteria are an experimental work-in-progress that stem from a wide range of different sources:
General knowledge of health & the gut microbiome.
Many of the studies listed above, and more.
A deep understanding of the underlying science of FMTs. We follow the latest scientific literature for new or conflicting data. Scientific studies are always the foundation for our decision-making.
The Anna Karenina hypothesis: “All happy families are alike; each unhappy family is unhappy in its own way.”
Human Microbes’ recipient results that are being systematically & publicly tracked & reported.
Personal experiences from people DIYing, including the founder’s dozens of FMTs from 13+ different donors.
Why Athletes?
I get asked this a lot. I find it surprising since to me it is very intuitive. At the base level, this is how the human body is supposed to function. Anything less than is defective and/or deficient.
Since the gut microbiome has been shown to impact and regulate virtually every aspect of human health and development, you want the most well-developed, high-functioning people – typically, top athletes. The quality of a person's gut microbiome would reflect in their physical abilities and attributes. So someone with an eubiotic/ideal gut microbiome should be very high-performing, well-developed, competent, intelligent, happy, etc. And due to the gut microbiome's role in the diseases of old age, including aging itself, donors should also be young. In contrast, a dysbiotic gut microbiome would limit/degrade a person's capabilities and physical attributes.
We need top young athletes in their prime.
Luckily, we don't have to rely on merely intuition and extrapolation. There is various scientific support for this already:
Human Microbes has now screened dozens of college and professional athletes. But none have met our ideal criteria, and only a small percentage are people I'd pick out of a lineup to be likely to qualify. There are a dozen or so who are very healthy & fit young athletes with bad stool types, and this type of applicant makes me feel like giving up. But I know that what I'm looking for exists, so I'll keep on looking.
One concern often mentioned is over-training. Top athletes regularly push their bodies to the limits, placing a huge strain on their bodies, i.e. causing inflammation, worsening intestinal permeability, etc. It is likely true that some high-performing athletes are damaging themselves from this. But it’s probably less so the case for the more naturally gifted athletes. And I believe these are the ones with the more ideal gut microbiomes that enable them to naturally excel.
Most of these super-donor types live in our society unbeknownst to themselves or others that their stool has the potential to rid hundreds of people of currently incurable diseases. But as time progresses, the number of super-donors available in the Western world decreases [1]. Antibiotics permanently damage the gut microbiome [1]; so once a super-donor takes an antibiotic, the curative powers of their stool are likely permanently diminished. Many microbiome researchers have been raising the alarm bells around this "microbial genocide" [1], yet it largely falls on deaf ears as most individuals remain apathetic about invisible health factors like the microbiome.
And FYI, it's in the interest of B-tier athletes that we find A-tier donors. Since high-quality donors are so rare, one of the first things we'll try to do is upgrade 7/10 and 8/10 donors to 9's and 10's by giving them FMT from 9's and 10's. The 7's and 8's would upgrade their own health, function, and performance, while also enabling themselves to start making money by being a donor. Hopefully this way we can start to exponentially reverse the chronic disease & extinguished-microbiomes trend.
That being said, neither of the two high-quality donors I temporarily acquired many years ago on my own were professional athletes. One was just a "normal" healthy & fit teenager. The other was a student-athlete, but nothing particularly special or renowned. So these people absolutely exist outside of the most exclusive circles, but for some reason they are very hard to reach and recruit.
Stool type
When I first started out 7+ years ago on my own, I created a donor screening questionnaire that tried to judge every aspect of health. That questionnaire plus a candidate's physical characteristics were what I was using to fully select and screen donors. Testing capabilities were/are very limited, and I was very poor. I had no idea if stool type was important, or which stool type was good/bad.
After trying 7 or so different donors, the two highest quality/most effective ones had identical stool types, as well as nearly identical questionnaires, and very similar physical traits. I then saw an article on the "Anna Karenina hypothesis". A Grand Unified Theory of Unhealthy Microbiomes. “All happy families are alike; each unhappy family is unhappy in its own way.”
This matched my experiences exactly. Since then, I have seen more evidence from both individual case reports, as well as clinical trials, to support this hypothesis. So it's one of the main things I've been looking for in a donor.
I've also seen from experience what antibiotics do to your stool. And I know what it looks like when your gut microbiome can't process certain foods, and/or is in a dysbiotic state or missing microbes.
After seeing hundreds of applicants’ stools & physiques, I don't even feel a strong need to test my stool type hypothesis anymore, since the correlation of stool type with physique is quite clear and consistent.
Yes, we're looking for top young athletes. But a top young athlete with a bad stool type won't qualify.
Identifying stool donors by looking at them
Health, and thus gut microbiome status, is reflected in our appearance. Another self-evident/common sense, intuitive conclusion I made from the start, which turned out to be surprisingly controversial [1].
After screening 23,000+ donor applicants, my intuition seems to have been correct. You can absolutely match physical traits with stool type. For the vast majority of people, I can simply look at them and tell they have a bad stool type and won't qualify; or I can look at their stool and know they have poor physical traits. Features such as adiposity, complexion, musculature, bone structure, symmetry, etc. There is a small percentage of people who have seemingly great physical traits but a bad/nonideal stool type. And those are very frustrating to review.
For some examples, I can see the facial features of people like Tom Brady and Christiano Ronaldo degrading as they age.
Giannis Antetokounmpo, Nikola Jokic, and Luka Doncic are all high-performing athletes, but Giannis is the only one who seems likely to be a high-quality stool donor.
Final words
If you disagree with my criteria you're welcome to test any of our donors. We maintain a list with a rough ranking of the top candidates. It would make things a hell of a lot easier if I were wrong.