The Human Microbiome is often referred to as the forgotten organ and can weigh anything from 1 to 3 kg which is effectively as much, if not more, than the human brain. The most active and diverse area of the Human Microbiome is of course the gut microbiota where there is not only a non-harmful coexistence but also a mutualistic or symbiotic relationship. The human gut has up to and maybe exceeding 1000 bacterial species that encode in excess of 5 million genes.
In addition to the gut, bacteria are present on human tissue and biofluids such as the skin, lungs, oral & nasal cavities and the vagina. Recent screening techniques have allowed us to detect and isolate species in what where previously perceived to be sterile environments such as the brain, urinary tract, the uterus and the biliary tract.
The first three years of life see frequent changes in the Human Microbiome. It has long been assumed that we are first introduced to microbes via the mother’s birth canal which is said to have a major influence on the future microbiome of an individual. It is also important to know that children delivered by C-section have reduced bacterial diversity compared to children from natural births. However, recent studies have also shown that there is some evidence of bacterial presence in the placenta and even in amniotic fluid.
What is certain is that the Human Microbiome becomes stable as from the age of 3. This stability is not static and there are microbial changes happening all the time which we still do not fully understand. These changes are influenced by many different factors such as diet, gender, lifestyle and habitat. More recent findings have shown that medication can also have an important effect on our Microbiome.
Human Microbiome is active in the digestion of our food and hence nutrition. It also influences our immune system through the production of a host of different metabolites which have an enormous influence, generally vital and positive, on our health. However, when our microbiome is in dysbiosis (a microbial imbalance due to the reduction in presence of beneficial bacteria being outcompeted by non-benefical or even pathogenic bacteria), it can result in complications and chronic diseases which can lead to serious conditions such as diabetes or heart and liver problems.