Embryos develop from a small ball of cells to a flat sheet of cells. This sheet rolls up into a tube. One end of the tube becomes the brain, the other end becomes the digestive tract.
There is communication along this brain-gut axis via nerves, hormones and the immune system (via the blood). And I’m probably not the only person who asked out loud for my stomach to stop growling, so there’s a cognitive connection too :).
There is some evidence that our intestinal micro biota, the bacteria that we harbor that aids in digestion, actually communicates with our brain via the immune system. Scientists are also investigating the hypothesis that modification of microbial ecology, for example by supplements containing microbial species (probiotics), may be used therapeutically to modify stress responses and symptoms of anxiety and depression.
A recent study from the Netherlands reported the first evidence that the intake of probiotics may help reduce negative thoughts associated with sad mood and suggest that probiotics supplementation warrants further research as a potential preventive strategy for depression.
The study was small, 40 people total for cases and controls, but it certainly works as a pilot study for more research.
The study was published with open access- you can read it here:
This also adds to the evidence that chocolate is good for us! Also, probiotics do not have to be taken as supplements. Besides chocolate, probiotics are found in fermented foods such as kim chi, and in yogurt.