Are the bacteria/parasites in your gut affecting your thinking?

I think it's a cute demonstration of materialism - "Behold! Not only is your mind a physical brain, but it's affected by your gut bacteria!" - but I don't see any further ramifications.

Interesting topic. There is such a procedure as a "fecal transplant" wherein fecal matter is taken from one person and put into another. To me this seems extreme and a little disgusting, but for people with severe illnesses (typically autoimmune or gut-related, as far as I know), sometimes drastic measures are worth trying. I have no idea if there is any material about this in the scientific literature, but at least to me, given what we are learning about the effects of the body's microbiota, it seems plausible. Who knows, maybe in X years geniuses will be auctioning off fecal transplants to those who want some of their brainpower.

From what I have seen, the effects of less extreme measures like eating Yogurt or taking pro-biotic supplements are quite modest.

Edit:

Found a post that discusses some of the findings in the medical literature related to fecal transplants. No links, unfortunately:

Fecal Transplants

Edit:

Apparently there is actually quite a bit of material on this in the medical literature. It dates back to 1958 and has been used in racehorses for years. Wired article: Fecal transplants work and Wikipedia page.

The writing in the abstract is a lot more obtuse,

The word you want is 'abstruse'.

There is the peculiar fact that when babies are born they turns their face towards the mothers bottom, that results in (often times) that mother's intestinal flora colonize the baby's intestine.

As a medical student who has been closely reviewing probiotic research, I would like everyone to know that research is extremely important.

Perhaps it will be the greatest breakthrough in medicine of the 21st century. This angle is one of the primary reasons that the 'calories in=calories out' theory doesn't function as a successful principle for people trying to lose weight and keep it off. I recommend looking into the GAPS diet for anyone suffering auto-immune problems, since auto-immune disorders are all primarily caused by dysregulation of the digestive system.

Some ideas on the yogurt study (also being an opportunity to explain some of the nuances):

1. there is an incredible breadth of biodiversity in the gut, and yogurt only typically contains one or two strains, in this case it looks like one.

2. gut bacteria number in the trillions, so a short-term regime of any probiotic food or supplement won't necessarily provide its benefits quickly. A significant amount of the benefit is also delivered in the chelating and detoxifying properties of healthy bacteria, which can over time remove harmful toxins built up in intestinal bile; a significant build-up may take years to fully flush though, and other health problems may still still inhibit it.

3. other things in the diet will impact bacterial growth just as much as the addition of yogurt. Foods high in sugar could very easily be inhibiting the multiplication of the yogurt's probiotic bacteria (after being ingested) by encouraging the growth of competing bacteria associated with negative health. Food eaten then also becomes the basis for the bacteria's food, so a poor quality diet could sabotage the probiotics.

4. the quality of the yogurt which the probiotic was added to will impact the growth of bacteria tremendously. The pasteurization process itself makes the yogurt less healthful and can create an environment less conducive to probiotic multiplication.

5. no distinction is made whether the stress can be considered 'justified' or not; it would be undesireable to be less stressful in a situation where stress is justified and helpful. The study also seems not to account for variance in difficulty of course load, since students may have signed up for classes with intuitive knowledge of the additional stress received through their usual gut bacteria.

6. there are also a variety of standard practices in preventing contamination, which I assume the group carried out

We have around 500 species of bacteria living in our guts. Yogurt uses only 2 or 3 species of bacteria. So it's not surprising that eating yogurt didn't change various aspects of behavior. If those behaviors are affected by gut bacteria at all, it's unlikely to be the particular strains found in yogurt.

The jury seems to still be out in infectious bowel disease.

The link is about inflammatory bowel diseases. These are not infectious.

That our health and body chemistry affects our mental processes, is not unreasonable to expect. More interesting would be if this goes the other way.. do our belief systems and rationality have a profound impact on our body chemistry?

For instance, I wonder if being rational and self-aware drives our digestive system to become clever over time.. consider that we may have a hoard of gastric juices which our body tries and tests on various kinds of foods, keeps a track of which works better, and adapts accordingly. It may also try to create newer juices and see how they work.. At the extreme end, we would be leading our body to set up a gastrochemistry lab in our guts.

Another example: I hope that studying computer science may lead one's own brain to apply those concepts to optimize one's neural connections in some way.. give us 'speedup', so to say.

Atovaquone treats toxoplasmocosis, which, together with genetic susceptability and other effect modifiers, may be one cause of schizophrenia. What existing data might exist to allow me to test this hypothesisi? Quick google searches suggests Atovaquone at the very least, tends not to be associated with anxiety or psychosis as side effects which for one is a good sign. Note, most schizophrenics aren't infected with toxo. they are just infected at a higher rate so it could explain a subset.

Here's a new report that suggets that children who are exposed to bacteria transmitted by dogs may be protected children from childhood asthma, because they bring about changes in our immune system which protect from a virus or because they change our gut flora. They carried out experiments on mice:

The researchers fed mice house dust from homes with dogs. They then exposed these mice to RSV and found that the mice did not show symptoms of infection -- airway inflammation and increased mucus production. They also compared the intestinal bacteria of dust-fed mice to mice that hadn't been fed dust and found differences in the types of bacteria living in the GI tract. These differences were seen whether or not the non-dust fed mice had been exposed to RSV.

I predict in the future psychiatrists will be more interested in our gut health than the brain directly... most mental illness seems to co-occur with unusual patterns of gut dysbiosis and loss of gut barrier function. In some cases the direction of cause and effect isn't clear, since rat studies have shown brain damage can result in gut dysfunction. This might even result in a positive feedback loop where mental dysfunction and gut dysfunction promote each other simultaneously. If so, such conditions would resist treatment, but may be permanently cured once treatment is successful and the feedback loop is stopped.

Exactly how to fix these issues is not clear, and is going to be more complicated than just taking probiotics or even transferring in desired bacteria directly (fecal transplants). In particular pre-biotics (substrate foods that promote growth of preferred bacteria), and removing molecules that often interfere with gut function (lactose, gluten, etc.) are likely useful as well.