Today we’re talking guts. Or gut bacteria to be exact.
Now we’ve long known that the gut is responsible for digesting food and getting rid of our waste. That’s kiddie stuff. And though it’s taken a while for Western medicine to embrace the ancient perspective that our gut hugely influences not just our physical but also our mental health, today leaders in science, medicine and nutrition all seem to be joining the gut parade.
A new research has been delving into the role our gut bacteria have to play in all this – especially how these billions of little guys affect our moods, our appetites, and even our cravings.
Scientists investigated the role that colonies of Escherichia coli (E.coli) bacteria living in our intestines play in what we eat. They discovered that the proteins these bacteria release when they’ve had enough nutrients influence the signals sent between the gut and the brain, and can even activate appetite-related neurons to make you feel full.
There are so many studies now that look at microbiota composition in different pathological conditions, but they do not explore the mechanisms behind these associations. Our study shows that bacterial proteins from E. coli can be involved in the same molecular pathways that are used by the body to signal satiety, and now we need to know how an altered gut microbiome can affect this physiology,” according to one of the researchers, Sergueï Fetissov from Rouen University in France.
Fetissov and his colleagues came to this conclusion when analysing the proteins produced by E. coli colonies living in the guts of mice and rats. At around 20 minutes after a meal, the bacteria started producing different kinds of proteins than they were before. Which is interesting, because in humans, this is around the time when we get that feeling of fullness and satisfied sleepiness after a big meal.
The researchers isolated these after-meal proteins, called ClpB, and injected them into mice to see if an increased dose would affect their appetites. They found that regardless of whether the mice had been eating a normal or restricted diet, they all displayed a diminished appetite and ended up eating less.
Publishing the the journal Cell Metabolism, the team says the proteins released by ‘full’ bacteria stimulated the release of a hormone called peptide YY, which has been linked to a feeling of satiety. They also found that the ClpB proteins increased the firing of neurons in the brain that are associated with a reduce appetite.
Well, we might be carrying around an incredible amount of microbes inside and on the surface of our bodies, but it’s in everyone’s interest that a certain balance be held in check. When populations of bacteria flare up or die out, it can cause all kinds of health problems that neither us or our microscopic hangers-on need.
With this in mind, it appears that the E. coli populations in our intestines keep careful tabs on their numbers, what more is that, it might be kind of embarrassing that tiny bacteria appear to be having a rather large say in how much we eat and when, but there is some good news.