Does stool donor sex and age matter? Are there differences in receiving fecal transplants (FMT) from male vs. female donors? And different age groups and enterotypes? Donors 

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coldcast

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I was curious about potential differences from receiving a transplant from a male vs. female donor.

I'm a middle aged male and I was confused between whether I should seek out a female or male recipient.

I'm leaning on finding a female donor considering that the mother provides the first major inoculation of bacteria for the growing baby (assuming natural birth and breastfeeding). I know that the mother is only the first, but not the only entity involved in inoculating us as we grow up.

I know that the donor should also be screened for a lot of different things, I'm assuming that this donor would pass on all other criteria, but its more the issue of their sex, age and enterotype that interests me.

Would it be better to receive from a younger person (like 14-15) or an older person? (35+)?

Also, another question, would it be better to aim for a particular enterotype? or is there an enterotype to receive from that is "totally okay"?

I was leaning on finding a donor with the Prevotella or Ruminococcus enterotype, but I know that the Bacteroides enterotype isn't totally bad either.

Would love to hear more from people who know about this. I'm a type 1 diabetic (born through C-section as well, not breastfead continuously) and have tried poring through the research as to what might be beneficial for me microbe wise. I even got a test of my gut microbiome and it's crazy that 26% of the bacteria in my gut are labeled as OTHER! I haven't seen that in other microbiome tests out there, and even saw some correlations with what is in my stomach with what has been presented in the research on people with Type 1 diabetes.

Anyways, would love an opinion or any thoughts on this. Thank you.
 
The evidence overwhelmingly supports universal donors (no need for matching). https://humanmicrobiome.info/fmt/

There's a section in the wiki that covers Donor-recipient matching: https://humanmicrobiome.info/fmt/#donor-recipient-matching, including evidence supporting and opposing the need for sex-matching.

If you scroll up a bit there's a section for Age as well. Plus: https://humanmicrobiome.info/aging/ which indicates that younger is generally better.

If you look at the humanmicrobes.org results (https://www.humanmicrobes.org/orders) there is no apparent connection between recipient-donor sex.

I've seen some people reporting they had a bad FMT outcome which they blamed on an opposite-sex donor, but these cases are almost certainly donor-quality related rather than donor-sex related. There are a lot of people with a poor understanding of human health and FMT donor quality and selection, and this leads them to use donors that they think are ideal but are actually quite bad.

coldcast said:
Also, another question, would it be better to aim for a particular enterotype? or is there an enterotype to receive from that is "totally okay"?

I was leaning on finding a donor with the Prevotella or Ruminococcus enterotype, but I know that the Bacteroides enterotype isn't totally bad either.
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coldcast said:
I even got a test of my gut microbiome and it's crazy that 26% of the bacteria in my gut are labeled as OTHER!
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Indeed. https://humanmicrobiome.info/testing/
 
I’m a female pursuing FMT for severe overgrowth of numerous harmful and pathogenic bacteria. I have a history of chronic gastritis and autoimmune disease I believe was triggered by the dysbiosis.

I’ve read virtually every Google result I can find on whether sex of donor matters for women but I do not see consensus. I have the choice of donor through my care provider, and I also know someone who may qualify independently but he’s male. If sex of donor doesn’t matter, I plan to have his stool sequenced with shotgun metagenomics to see if my hunches based on his athleticism and physicality match reality.
 
Michael Harrop said:
That is not a viable approach. Those tests are extremely limited in value https://humanmicrobiome.info/testing/.

For donor selection information, see:
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I read the links but I am still not sure to what extent shotgun metagenomics which reports on strains (which the Thorne test does; I have numerous bacteria like Fusobacterium nucleatum reported out to the strain level) is "limited" except in so much as any of our knowledge of the biome and its inhabitants might be limited at this point in history. Is there a better option in your mind? Do you think the test has no utility at all, or that it is just not useful for selecting FMT candidate. The FMT candidate I am considering meets all of the criteria you outline otherwise. He would in fact be someone you'd pick out of a lineup. My clinic has 6 donors, 2 children, and 4 adults who they claim have zero lifetime antibiotic use. I believe it for the children, perhaps am a bit skeptical for the adults. I don't have my consult with them for another couple weeks however so I'm awaiting more information on them.

One of my numerous problems is a stool sequencing profile resembling the gastric cancer patients described here: https://www.gastrojournal.org/article/S0016-5085(22)00143-3/fulltext. I am 99.9 percentile for both S. anginosus and constellatus. I believe it's at least plausible the anginosus could be behind my years of unexplained and hard to manage chronic gastritis. The gastric cancer patients whose stool was analyzed had anginosus counts 22 fold the average "healthy" person, for instance. That's me, unfortunately. I guess I'm finding it hard to follow the argument the tests are "extremely limited in value" if studies like the one I linked to are showing utility of counting various bacteria in stool and linking them to disease. I would very much like to hear your opinion.
 
smallish said:
Do you think the test has no utility at all, or that it is just not useful for selecting FMT candidate.
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It depends on the specific test and which parts of it. For example, the GI Map has many of the tests recommended by official guidelines. It also has a lot of "largely useless" info, and it's that other information that is being sold/marketed to many people under misleading pretenses. This section in particular covers that: https://humanmicrobiome.info/testing/#commercial-testing

For the info that you seem to be talking about, I would say "virtually no utility".

smallish said:
The FMT candidate I am considering meets all of the criteria you outline otherwise.
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How did you verify and judge their stool characteristics? I continually see people claiming their donor is perfect without mentioning stool characteristics.

smallish said:
One of my numerous problems is a stool sequencing profile resembling the gastric cancer patients described here: https://www.gastrojournal.org/article/S0016-5085(22)00143-3/fulltext
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I covered this in the #2 post above. There are many studies finding certain signatures for various conditions. That doesn't mean it's a valid approach to target those specific microbes or rule out stool donors who have some similarities. You need to think of the gut microbiome as an extremely complex ecosystem. Thinking that you can narrow it down to a handful of genera or species is naive. With FMT you are trying to restore the entire ecosystem to an eubiotic state. And it's largely unknown what the important components of a high-quality donor's stool are. The information I shared on H. pylori and candida are good examples.

What are you going to do with a test high/low in S. anginosus and constellatus? Those types of results are not a part of any of the FMT donor screening guidelines and should not be a part of FMT donor selection at all. What about all the other conditions associated with high/low other genera or species? You would need a database of all the results, and some kind of statistical or AI analysis of the data. There are often mixed results over various studies, especially when taking into account many different conditions (which you should be for FMT).

As mentioned, there is a good reason why these tests are not recommended for FMT donor screening (yet).

I have screened over a million stool donor applicants and have done countless FMTs from 13+ donors, and I have found that observable stool characteristics are one of the best ways to judge donor quality. And another patient who has done FMTs from a similar number of people, including the Hadza, agrees with me.

Of course you're free to spend your money as you like and make your own decisions. My opinion is that using those kinds of test results to screen donors is not valid and is a waste of money. And if you have that kind of money to "throw away" I think there are better ways to spend it (Eg).
 
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