[kawera]

An old but interesting article and discussion related to your question:

http://www.theatlantic.com/magazine/print/1969/12/how-your-c...

https://news.ycombinator.com/item?id=3573694

Articles somehow related to the subject:

http://www.nature.com/news/the-tantalizing-links-between-gut...

http://universityofcalifornia.edu/news/do-gut-bacteria-rule-...

http://www.scientificamerican.com/article/gut-second-brain/

http://www.theverge.com/2013/8/21/4595712/gut-feelings-the-f...

http://newsroom.ucla.edu/portal/ucla/changing-gut-bacteria-t...

[n0us]

Thanks for all of the sources. I remember listening to a talk on NPR about the same subject a while back in my car but I couldn't find a link to it.

[kawera]

Maybe this: http://www.npr.org/sections/health-shots/2012/07/02/15614221...