I'm a bit obsessed with gut bacteria at the moment. I've been brewing kombucha, fermenting kimchi... I even bought a yoghurt maker! New research keeps popping up linking the gut microbiome to everything from metabolic syndrome to depression risk. So here's a little run-down on gut bacteria: The gut microbiota and microbiome explained: Our gut is home to trillions of bacteria, viruses and other microbes referred to as the gut microbiota, while the genetic material inside these cells are what we call the gut microbiome. The entire microbiota in our gastrointestinal tract weighs between 0.5 to 2 kilograms. One-third of our gut microbiota is common to most people, while two-thirds are specific to each one of us. This makes our gut microbiome as unique as our fingerprints. The gut microbiome is not a static thing. It changes throughout life after first colonising the gut shortly after birth and continuing to gather new members from the environment throughout life. Variation is highest during childhood, and it gradually decreases with age. Illness, antibiotic use, fever, stress, injury and dietary changes all affect the blend of microbes that make up the microbiome. Gut bacteria research: There are really exciting new discoveries being published and further research underway, including: -  Weight loss - Overweight and healthy weight twins were found to have significant differences in gut microbiota, with less diversity found in within the overweight twin. When their gut bacteria were transplanted into mice, those with the overweight bacterial transplant gained weight, while those with the healthy weight bacteria didn't. - …