The different compartments of the gastrointestinal tract are inhabited by diverse populations of microorganisms often governed by the pH of that environment. By far the most important predominant populations are in the colon, primarily the large intestine.
It was originally believed that the composition of the intestinal microbiota was relatively stable from early childhood; however, overwhelming evidence now shows that diet, environmental and lifestyle factors have a large influence on your gut microbes. Some bacteria such as Escherichia coli (E. coli) can double their numbers in 20 minutes.
More than 99% of bacteria are found in the intestines, with as many as 500 to 1,000 different species, as well as yeasts (moulds), viruses and parasites. We have some 100 trillion bacteria in our gut, they aid in the digestion of food, provide a constant supply of nutrients such as B vitamins and amino acids, produce important substances such as vitamin K, improve mineral absorption and help the body fight off harmful bacteria. These good bacteria are essential for a healthy gut and crucial to our overall health and wellbeing.
Association between fungi and the GI tract has been documented since the eighteenth century, particularly candida and more recently much evidence has shown that fungi and their communities may be involved in many gut health problems. More than 50% of patients with gastric ulcers present with gastric fungal colonisation, which often appears among the elderly population with low gastric acid.