"90 % of the cells in your body are bacterial cells and only 10 % are our own human cells."
The gut bacteria digest certain foods, produce essential vitamins and hormones, respond to medicines and infections, control blood sugar and blood cholesterol levels.
“If mice become colonized by the microbes Toxoplasma gondii , they lose their fear of cats. They actually become attracted to cats”. The gut microbiome might even control the way people think and behave, by sending and receiving signals from the brain via the Vagus nerve and by producing the majority of neurotransmitters.
Very useful is the list of probiotics, those foods that stimulate the "growing" of healthy bacteria inside of our intestines (10:57).