It is believed to be involved in the development of chronic inflammatory intestinal diseases, to trigger diabetes, to be responsible for obesity, even neurological diseases such as multiple sclerosis and Parkinson’s could have their causes here – not to mention depressions and autistic disorders. We are talking about the microbiome – the vast collection of bacteria in the human gut. It is estimated that each person carries around 100 trillion bacterial cells in their digestive tract, belonging to several thousand species.