Our intestinal tract is inhabited by a large and diverse population of bacteria, this is collectively termed the gut microbiota. The average human gut microbiota contains about 100 trillion bacteria (ten times more cells than in our body) which in total, weigh up to 2kg! There are more than 3 million microbial genes in our gut microbiota, this is 150 times more genes than in the human genome¹  

Within our gut microbiome there are 500-1000 distinct species present that provide several benefits including; 

  1. Helps the body digest certain foods that the stomach and small intestine have not been able to digest 
  2. Helps with the production of some vitamins (B and K) 
  3. Reduce the risk of pathogens within our intestines and maintains balance 
  4. Plays a role in the immune system, performing a barrier effect(¹,²).

Our gut microbiota starts developing in the foetus and evolves throughout our entire life. The gut microbiota balance can be affected during the ageing process and therefore, the elderly has a substantially different microbiota compared to young adults. Whilst the general composition of the gut microbiota is similar in healthy individuals, the species composition within our gut microbiota is unique and determined by our environment and diet¹. The gut microbiome can become affected by several factors including; medication, stress and a poor diet.

If the gut microbiota becomes imbalanced (dysbiosis) it can contribute to the development of illness and disease. Evidence has linked our gut microbiome to conditions including acne, allergies, Irritable Bowel Syndrome (IBS) and depression³. Additionally, evidence has suggested there may be a link between the gut microbiome and neurodegenerative diseases such as Parkinson’s as well as obesity, and autoimmune conditions such as Type 1 diabetes³.  

If you'd like to learn more about the gut microbiome, why not book a free 1:1 consultation with our nutrition team? We can recommend diet and lifestyle changes that can make a big difference. To book, simply click here.


  1. Gut Microbiota Info - Gut Microbiota for Health [Internet]. Gut Microbiota for Health. 2019 [cited 28 August 2019]. Available from: https://www.gutmicrobiotaforhealth.com/en/about-gut-microbiota-info/
  2. Chassaing B, Vijay-Kumar M, Gewirtz A. How diet can impact gut microbiota to promote or endanger health. Current Opinion in Gastroenterology. 2017;33(6):417-421. 
  3. How does diet affect gut health? [Internet]. BBC Good Food. 2019 [cited 28 August 2019]. Available from: https://www.bbcgoodfood.com/howto/guide/how-does-diet-affect-gut-health