Stressed out by the upcoming holidays? Maybe some interesting studies about the microbiome could be a good distraction.
Your brain acts on your gut, shaping its microbial makeup, while your gut is busy manufacturing neurotransmitters including dopamine, gamma-aminobutyric acid (GABA) and serotonin.
In fact the vast majority of your serotonin originates in your intestine.
Talk about gut feelings, eh?
Researchers at McMaster University in Ontario were able to change the behavior of germ-free mice by colonizing their intestines with bacteria from other mice—giving them what you might call a poop-personality transplant.
This led naturally daring mice to become apprehensive and shy, for example, leading scientists to suggest that microbial interactions with the brain could induce psychological change.
Although some are understandably uncomfortable with experiments such as these, other researchers from McMaster later joined forces with scientists from University College Cork to show that mice fed a broth containing Lactobacillus rhamnosus were far less likely to relapse into “behavioral despair” when dropped into a tall cylinder, from which there was no escape, than mice without these microbes.
The same experiment has been used to test antidepressants, leading one scientist to suggest that the broth-fed mice were behaving as though they were on Prozac. Lactobacillus rhamnosus is a bacterium commonly found in the human body, and also used in the fermentation of milk as it is turned into yogurt.
It hasn’t all been about mice, however.
A 2013 proof-of-concept study at UCLA showed through fMRI scans that women who ate yogurt containing active probiotics twice a day for a month showed a reduced reflexive response to photos of actors with frightened or angry faces.
The researchers warned that their results were rudimentary, but there was at least an indication that consumption of probiotic bacteria such as Bifidobacterium animalis subsp Lactis, Streptococcus thermophiles, Lactobacillus bulgaricus, and Lactococcus lactis subsp Lactis could have been making the participants less prone to anxiety.
Another study, in Norway in 2014, found significant correlations between bacteria in stool samples and depression, with elevated levels of the order Bacteroidales and a reduced abundance of the family Lachnospiraceae.
Enjoy this season of getting ready and try to keep your “to-do” list short. For more information on microbes and some words from Hippocrates, read our classic blog post.
If you are interested in learning more about your health and your microbiome come check out our clinical microbiome test SmartGut™.