Research on gut bacteria may change the way we look at anxiety, depression, and behavioural disorders.
If aliens were to examine a human, they would think we were just slavish organisms designed to feed microbes and carry them around. Our bodies contain ten times more bacteria than cells, and there are an estimated 3.3 million genes in the total bacteria DNA, which is 160 times the number of human genes. Our intestine hosts about one kilogram of bacteria which help to digest and metabolise food, produce vitamins and protect us from infections.