Inside your gastrointestinal (GI) tract are trillions of micro-organisms, including bacteria, fungi and viruses. You have roughly the same number of micro-organisms in there, mostly in the large intestine, as you do human cells in your entire body. But only 10% to 20% of the bacteria you have in your gut will be shared with anyone else.
These microbiomes differ hugely from person to person, depending on diet, lifestyle and other factors, and they influence everything from our health to our appetites, weight and moods. But despite being one of the most-researched parts of the body, there’s still a long way to go to fully understanding our guts. BBC Future reviewed the findings of some of the science so far.
“C-section-born infants miss out on that initial inoculation, and some of the microbes they come into contact with will be from the skin and environment” says Hall.
“This is very important for infants to develop their immune systems. Recent work has suggested that disturbances in early life gut microbiome have negative consequences for host health,” she says.