The problem is that the answer may be "literally thousands of different types of bacteria".

Your digestive tract is a jungle, with more species than man will ever fully know about. When too many of certain types go extinct, the ecosystem breaks down, and bad shit starts to happen (come to think of it, literally).

It may take decades to figure out all of the specific species that matter most, and in what proportions. We aren't even certain which bacteria are common to all people, and which are specific to certain cultures / races / geographies / genders / who-knows-what-else. I bet people who eat a lot of KFC have a very different personal biome than I do.

In the meantime, here's 'one weird trick' that seems to just work.

>" than man will ever fully know about"

The more this works, the more we'll be inclined to study it. We'll know eventually.

Bacteria evolve faster than we can isolate and sequence them.

Even brewer's yeast is discarded after a few generations, usually, since it mutates enough to change the flavor of the resulting beer, and that's in an extremely well controlled environment.

Imagine that happening every six weeks in your gastrointestinal tract. Multiply by 6 billion people. I'd guess it's extremely unlikely we're going to thoroughly investigate all of those different variations on the theme.

Take a large sample of people and find out patterns in their gastrointestinal bacteria, and run the numbers.

Is it out of the question for people to be consistently pooping & supplying this data so we have ongoing tracking of the ratios of the various bacteria present in the population? Some clear patterns may arise.

Clear patterns did arise when the Human Microbiome project did this :)

http://academy.asm.org/images/stories/documents/FAQ_Human_Mi...

That represents the consensus view (ie no exotic theories). The really good stuff starts on page 10.

This is actually really interesting, thanks for sharing.

They talk about mother's milk/breast milk being a source of microbes for babies at birth. I have heard this before and I wonder if it could be an alternative to this pill/fecal transplants?

It depends what you're using the feces to accomplish. Usually FMT is done for people suffering from CDiff infections. The healthy gut flora outcompete the CDiff, causing the infection to go away.

Mother's milk is mostly viruses, so it's unlikely this would work against CDiff. For other users is sounds interesting though!

TIL ^^ .. Awesome.

Depends. Species might come and go, depending on how dynamic the evolutionary environment is there.

We aren't planning to launch on HN until monday... though I'm guessing this far down the thread we won't get a huge spike in traffic.

> Can they please figure out which bacteria are actually important and then I will take that? Instead of eating actual shit. Thanks.

That's exactly what my co-founder and I are doing :) http://www.generalbiotics.com/probiotics

We all eat small amounts of shit all the time. That's how microflora colonize your gut in the first place. Furthermore, many of these organisms can not be cultured outside the body or freeze-dried and preserved in a shelf-stable yet still viable form. Shit is the only game in town.

Millions of flies can't be wrong!