Understanding the Gut

The Gut Microbiota (GM)

Microorganisms (mainly bacteria and some fungi) live in all parts of our body that have contact with the exterior world around us – the mouth, the skin, the gut, the vagina and even our eyes, believe it or not. The microorganisms that live in our gut are known as the ‘Gut microbiota’ (GM) and most of these live in the colon or large intestine.

Gut bacteria , gut flora, microbiome. Bacteria inside the small intestine, concept, representation. 3D illustration. Gut bacteria , gut flora, microbiome. Bacteria inside the small intestine, concept, representation. 3D illustration.

What we know about the GM 

  • There are a lot of microorganisms inside us. Over 50 trillion bacteria live in the colon and the average person has between 300-1,000 different bacterial types in the GM, although 30-50 bacteria usually dominate in any one person
  • There is no one specific bacterial mix or pattern of GM, no ‘GM signature’ that indicates that someone is healthy or that the GM mix is a healthy one. However, we know that having lots of different bacteria is good – plenty of diversity, this is called microbial diversity, and in general, ‘the more the merrier’.  We can achieve GM diversity by having plenty of variety within our diet. Reduced diversity and altered bacteria of the GM is known as dysbiosis
  • The GM is not a passive bystander in your gut; it is very active and produces lots of substances – chemicals and hormones – that interact with our bodies in hugely complex and poorly understood ways. The GM also produces many vital vitamins including vitamin K and the B vitamin group, as well as chemicals such tryptophan (a precursor of serotonin which is vital to our mental health), dopamine and short chain fatty acids (SCFAs)
  • Dysbiosis has been associated with many different medical conditions such as Crohn’s disease, ulcerative colitis, IBS and even diabetes to name but a few. It is still not entirely clear if dysbiosis is the cause or the result of the particular medical condition
  • The GM of men and women are different. The GM has been shown to be involved in producing oestrogen
  • Your diet has a huge impact on the make-up of your GM. In general, diversity in your diet leads to diversity of your GM.  Foods that alter the GM in a beneficial way are known as Pre-biotics. Fibre, from plant-based foods is one of the most important foods for your GM and has been shown to increase the number and the diversity of the GM
  • Diets high in animal fats and processed foods have a negative effect on GM
  • Many forms of alcohol reduce GM diversity