Our bodies contain more microbes (bacteria) than human cells and our gut bacteria (or microbiome) is established at birth when bacteria are transmitted from mother to baby. This microbiome then develops fully during the first 2-3 years of life as the baby is exposed to different external factors.
The microbiome is vital to support a healthy life and, once it is developed, each of us has around 100,000 billion viable bacteria living in our intestines. These bacteria comprise around 1,000 different species and 5,000 strains and weigh around 1.5kg in total. They do not live in our stomach as the environment is too acidic for the bacteria to survive but are a key part of the physiology of our small and large intestines. 95% of the bacteria reside in our large intestine where the layer of bacteria on the gut wall is up to 200 cells thick.
Everybody has their own individual microbiome, which is influenced by our diet, environment, lifestyle, genetics and early exposure to microbes. We all carry both good and bad bacteria in our guts and it is the diversity and balance of these bacteria that is key to supporting health.
Lactobacillus and Bifidobacteria have been identified as the two most helpful bacteria species in the human gut microbiome and are the species of bacteria most widely researched to date.