There are between 300 and 1000 different species of in your gut, totalling over 100 trillion microorganisms. There are between 5 and 50 trillion cells in the human body. That means there are
more of them than there are of you. Creeped out?
To some, bacteria is a bad thing. This is why antibacterial soaps and hand cleansers are a multi-billion dollar industry, predicted to reach over $40 billion by 2016. However, people are starting to understand just how vital those microscopic bugs are for our existence. Take your gut, for example, your GI tract, the poop-shoot, that single long tube that turns food to fertilizer (Disclaimer: human feces is not a good fertilizer). There's bacteria in the biofilms of the mouth, bacteria in the stomach and perhaps most importantly, bacteria in the small and large intestine that help digest carbohydrates and absorb fatty acids. This same gut microbiome is increasingly thought to directly influence brain function as well. That's gut bacteria, playing a role in your personality.
You can't function without them because they protect you. They help digest your food. They produce amino acids that you can't survive without. There is plenty of research that shows just how integrated you are with your little friends. The health of the gut microbiome is being linked to obesity, bone health, immune function and mental health. And this is no longer new and surprising (to most people). The scientific community at large has accepted the fact that we are covered inside and out with some extra friends that we heavily rely on.
So why are people so resistant to new research showing that a parasite from cat intestines may be controlling our brains?
Wait. What?
A handful of studies on Toxoplasma gondii, (all linked from this article, which what got my attention in the first place) have shown some personality quirks that are far more prevalent in those tested for the parasite. These individuals are more likely to be uncoordinated enough to have more car accidents, less likely to seek out new experiences, and they show a higher correlation with schizophrenia. Unlike your gut-dwelling friends, there seems to be little positive outcome from contracting T. gondii.
The research of one of the experts in this area, Jaroslav Flegr, hadn't been taken seriously by many for a good portion of his career. People are resistant to the idea of parasites controlling their personality to such a degree.
However, upon further reflection, it doesn't seem that unlikely. If there are bugs controlling so many aspects of our physiology, from weight to mood, why wouldn't they have an affect on personality too? As uncomfortable as it is to ponder, as time goes on, it wouldn't be surprising if we discover even more of "them" controlling us. It's just one more reminder that humans are inextricably linked to the world around us.
