Gut Feelings

Interesting research which reminded me of a prior post.

From Discover...

From “gut feelings” to “having some guts”, English is full of phrases where our bowels exert an influence upon our behaviour. But these are more than metaphors. There are open lines of communication between brains and bowels and, in mice at least, these channels allow an individual’s gut bacteria to steer their behaviour.

The latest evidence for this “gut-brain axis” comes from Javier Bravo at University College Cork. He fed mice with a probiotic bacterium called Lactobacillus rhamnosus, often found in yoghurts and dairy products. The bacterial menu changed the levels of signalling chemicals in the rodents’ brains, and reduced behaviours associated with stress, anxiety and depression.

It may seem odd that bacteria in an animal’s gut can control what happens in its brain, on the other side of the body. But the two organs have a direct line between them – the long, branching vagus nerve, which transmits information from the gut and other visceral organs to the brain. When Bravo severed the vagus nerve in his mice, Lactobacillus lost all of its influence. It changed neither the rodents’ behaviour nor their GABA receptor levels.

Bravo’s study is the latest in an accumulating body of evidence showing that gut bacteria are little backseat drivers for their hosts. “We have no reason to expect that the same would not apply to humans,” says Cryan. “However, such clinical studies need to be carried out.”