The Microbiome Inside Us All

30/10/2015

The human microbiome refers to the very large community of micro-organisms that live in and on the human body, including a range of bacteria, fungi and archaea. While some of these organisms perform known tasks that are essential to our basic survival, the role of most microbiota is completely unknown. Non-human organisms exist everywhere on the human body, with large communities existing on the skin, inside the mouth and lungs, and throughout the gut region. 

Widely recognised as a "forgotten organ", the gut microbiome is incredibly important to how we survive and function. A wide range of bacterial flora can be found throughout the gut, including micro-organisms that aid digestion, synthesise vitamins, and create enzymes not produced by the human body. While a balanced gut helps you to digest the foods you eat, an unhealthy gut colony can influence conditions such as irritable bowel syndrome, diabetes and obesity.

While the connection between the human microbiome and certain medical conditions is well understood, the links between microbial levels and mental health is only starting to become recognised. A balanced microbiome is thought to greatly influence mental health and emotional well-being on a number of levels, with the "forgotten organ" also referred to as the "second brain". Microbiota and mood are intricately related, with intestinal disorders coinciding with high levels of major depression and anxiety and paediatric disorders including autism and hyperactivity.

Dysbiosis, bacterial overgrowth and intestinal permeability are all known to cause inflammation and increase toxic exposures in the brain, with neurotransmitters and hormone levels both disrupted as a result. According to Christopher Coe from the Harlow Primate Lab, it may even become possible to treat mental health disorders by working with the microbiome: "It seems plausible, if not yet proved, that we might one day use microbes to diagnose neurodevelopmental disorders, treat mental illnesses and perhaps even fix them in the brain."

The microbiome is greatly affected by bacteria, yeasts, moulds and dirt, with the foods we eat on a daily basis also contributing to our microbiotic health. We can affect the microbiome balance by eating more fruits and vegetables and naturally fermented foods like yoghurt and kefir, together with foods such as sauerkraut, kimchi, tempeh and raw vinegar which are high in beneficial Lactobacillus bacteria. Garden herbs and fresh fish are also beneficial, with exercise also shown to boost gut microbiota diversity when combined with a balanced diet.

Research into the human microbiome continues to expand our awareness about the world within, with more studies being released all the time. According to Tom Insel, the director of the National Institute of Mental Health in an interview with the NY Times, ‘‘It has enormous implications for the sense of self... We are, at least from the standpoint of DNA, more microbial than human. That’s a phenomenal insight and one that we have to take seriously when we think about human development.’’