Poster Presentation Lowitja Institute International Indigenous Health and Wellbeing Conference 2016

A healthy environment viewed through the gut microbiome (#306)

Leonard C Harrison 1 , Robert James 1 , John M Wentworth 1 , Kerin O'Dea 2
  1. Population Health and Immunity Division , Walter and Eliza Hall Institute of Medical Research , Melbourne , Victoria , Australia
  2. School of Population and Global Health , University of Melbourne , Melbourne , Victoria , Australia

Health and disease can only be understood within the contexts of ecology and culture. At the physical interface with the external environmental resides the microbiome—the collection of microorganisms (bacteria, fungi, archaea, protozoa and viruses) on our mucosal surfaces and skin and in our secretions, that greatly outnumbers our own cells and genes. Humans harbour more than 10,000 bacterial species, at least 3,000 of which are in the gut. The critical importance of the microbiome to human life has emerged only in recent years, due to the advent of high throughput DNA sequencing. While much of its functional complexity remains to be understood, the microbiome produces a vast array of peptides, polysaccharides, lipids, biochemical groups and compounds, enzymes and vitamins that are essential for normal development and function of the different body systems (immune, endocrine, nervous etc.). Many of these microbiome products alter the chemistry of our DNA ('epigenetics') and thereby influence the expression of our genes. The gut microbiome in particular also contributes to energy utilisation by the body. Colonisation by microorganisms begins at or even before birth. The composition of the microbiome can be disrupted by many environmental and lifestyle factors, including the mode of birth (e.g. vaginal versus Caesarian section), antibiotics, dietary components including non-food additives such as preservatives, artificial sweeteners and emulsifiers, pollutants and toxins and living conditions. A so-called 'Western' diet, high in saturated animal fat and sugar and low in complex starch-fibre and overall diversity, substantially decreases the compositional complexity of the gut microbiome within days. Studies in animals and humans demonstrate that infectious diseases (e.g. Clostridium difficile diarrhoea) and non-infectious disorders (e.g. obesity–diabetes) can be transferred or treated by manipulating the gut microbiome.

It is suggested that studies of the microbiome from early life and in relation to different environmental conditions and circumstances would contribute to our understanding of ill-health and its prevention at a population level.