The gut microbiome and its role in both health and disease has been the subject of widespread research, with professors Matthew Bull and Nigel Plummer confirming its involvement in human metabolism, nutrition, physiology, and immune function in Part 1: The Human Gut Microbiome in Health and Disease published in Integrative Medicine Volume 13. 

The gut microbiome and its role in both health and disease has been the subject of widespread research, establishing its involvement in human metabolism, nutrition, physiology, and immune function.

“The use of probiotics as health beneficial products is huge and there is a constantly rising number of different functional foods and pharmaceutical products,” said Professor of microbiology at the Russian Academy of Sciences, Dr Alexander Suvorov (Gut Microbiota, Probiotics, and Human Health published in Bioscience of Microbiota, Food and Health Volume 32).  


The microbiome is the genetic material of all the microbes (bacteria, fungi, protozoa, and viruses) that live on and inside the human body, and is essential for human development, immunity, and nutrition. According to Dr Suvorov the gut microbiome in turn participates in almost all metabolisms of incoming nutrients, is involved in vitamin synthesis, in cholesterol catabolism, shapes numerous immune reactions related to the innate and adaptive immunity, and modulates the relationship of the human being with pathogenic microorganisms.  


“The human gut microbiota is made up of complex and diverse microbial communities that are associated with human intestinal health, said Dr Jose Clemente et al. (The impact of the gut microbiota on human health: an integrative view published in Cell Volume 148). The gut microbiota is thought to be composed of close to 100 trillion microbial cells that offer a variety of metabolic functions to the host explained Dr Seon-Kyun Kim et al. in Role of Probiotics in Human Gut Microbiome-Associated Diseases (published in Volume 28 of the Journal of Microbiology and Biotechnology). “For examplethe intestinal microbiota plays an important role in the degradation of plant-derived complex carbohydrates. Also, they are known to perform multiple functions in the host including intestinal development, homeostasis, and protection against pathogenic bacteria.”  

Normal gut microbiota is the body’s first internal line of defence against pathogens and toxins, which protect the body against disease in conjunction with the host immune system said gastroenterologists Dr Mayenaaz Sidhu and Dr David van der Poorten (The gut microbiome published in Australian Family Physician Volume 46). “One of the most important functions of a healthy microbiome is to prevent the colonisation of pathogens through a barrier effect. Gut bacteria are also crucial to the development of the mucosal innate immune system via direct interactions with intestinal epithelial cells. Early exposure to a wide range of bacteria provides a sort of training for the immune system.  


“The body of evidence concerning the use of probiotics in medicine is substantial,” said Dr Suvorov. The body uses probiotics to improve the homeostasis of internal microbiota to maintain human intestinal health. “Consequently, the number of harmful bacteria that cannot survive in an acidic environment is decreased, and the beneficial bacteria that grow well in an acidic state proliferate, thereby balancing the intestinal microbiota,” explained Dr Kim et al.  

However, not all probiotics are the same, different strains of the bacteria have different effects. According to Harvard Health Publishing, potential benefits of probiotics have been seen in the treatment or prevention of:   

  • Diarrhoea 
  • Irritable bowel syndrome (IBS) 
  • Ulcerative colitis 
  • Crohn’s disease 
  • H. pylori (the cause of ulcers) 
  • Vaginal infections 
  • Urinary tract infections 
  • Recurrence of bladder cancer 
  • Infection of the digestive tract caused by Clostridium difficile 
  • Eczema in children 

While it’s clear that gut microbiota is both complex and critical to human intestinal health, the more research that’s done, the better we understand the role probiotics may play in restoring and maintaining not only digestive but immunological and respiratory functions too.