Gut bacteria or gastrointestinal bacteria affect the brain and how it functioned. This was the findings of Emeran Mayer, a gastroenterologist from the University of California, Los Angeles,

Mayer studied several patients suffering from autism. People who suffer from autism had difficulty in establishing relationships with other people. This was because they cannot communicate well using language and other abstract ideas. Mayer noted that majority of people suffering from autism had gastrointestinal tract that malfunctioned. This led him to connect autism to the bacteria that are found in human intestines and other parts of the digestive system, according to The Science Times.

The gastrointestinal tract is inhabited by plenty of bacteria. They helped in proper digestion of food. However, the onset of bad bacteria can cause an imbalance. This led to the malfunctioning of the gastrointestinal tract which was believed to affect the brain.

Scientists from the University of Alabama in Birmingham were also able to connect gut bacteria to Parkinson's disease. In the past, this disease was believed to caused by a part of the brain that controlled mobility. However, recently, it was noted that majority of people with Parkinson's had malfunctioning gastrointestinal tract. This made scientists conclude that Parkinson's disease and autism were affected by gut bacteria, according to Science Alert.

Introducing probiotics or live bacteria good for health was found to be effective in treating autism. Fermented milk products were known to contain good bacteria. To see if it affected gut bacteria, mice showing signs of depression and anxiety were given fermented milk. They manifested reduced level of anxiety and depression.

Scientists looked forward to giving probiotics to people suffering from autism or Parkinson's. The same results as with the experiment in mice would be a breakthrough in the field of gastroenterology. It would also give answers to the mysterious relationship between gut bacteria and the brain.