Several studies have revealed that there is a strong connection between the type of bacteria that is in our gut, our brain chemistry and behaviors associated with that bacteria. Some scientists believe that the bacteria found in our digestive system may help to mold our brain structure and possibly influence our moods, behavior, and feelings.
In one study on mice changes in brain chemistry and behavior were reported when scientists replaced gut bacterial of anxious mice with bacteria from fearless mice. These mice became less anxious and more outgoing. The opposite became true when bold mice received microbes of anxious mice. This study revealed the strong connection between what goes on in the intestine and how our brain responds to such (Stein, 2013).
A separate study was conducted on mice who exhibited autistic-like behaviors such as anxiety, sensorimotor, and communication abnormalities. These mice were given a probiotic which significantly reduced, if not corrected their behaviors. This again displays the significant need for intestinal health and its role in behavioral symptoms (Hsiao, 2013).