Hate GMOs and think bioengineering is bad? What if it could help you with obesity and depression?

Well then I don't hate them as much. Dammit. 

I like it ;)

Me too!

Let's start with some background. What is the microbiome?

There are 100 trillion microbes living upon and within our bodies. That's 10 microbes for every one of our own cells. They are on our skin, they are in our mouth, and a lot of them are in our stomach and intestine.

How do these microbes affect our health?

We've recently done a lot of mapping to figure out which microbes are where, and how sick people with different diseases have different microbes in different locations. It is looking more and more that our microbes not only play lots of essential roles in the metabolism and immune function in healthy people, but they can also be the origin of diseases. So if there is a disruption in some of these microbial communities, it can lead to a wide range of diseases, just like if you have a genetic mutation in your liver or heart.

I get that microbes can affect us physically, but how do they affect our mood?

There is something that researchers are calling the gut-brain axis. We think this happens via the vagus nerve, which connects your intestine to your brain.

A recent study shows that the microbes inside your large intestine are sending signals to your brain, which affects anxiety and related behaviors. The researchers did an experiment with mice where they removed the vagus nerve, and the gut microbiome no longer affected the brain.

It is also likely there are other connections through the fluids in your body.