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Importance of the Intestinal Microbiota in Health and Disease

The cause of many non-infectious human disease (autoimmunity, allergy and cancer) all represent dysregulation of the immune system. And one of the main areas in which the immune system comes into contact with the outside microbial filled world is in the gastrointestinal tract. Accordingly, the microorganism populations of the gastrointestinal tract have been shown to have a direct relation to the state of our immune system [1].

Research in this areas suggest that the composition of the intestinal microbiota has a direct influence on an individuals susceptibility to a variety of chronic disease. Including diseases of not only the intestinal tract, such as ulcerative colitis, Chron’s, celiac disease and IBS, but also systemic disease such as obesity and diabetes [2].

More specifically, there appear to be specific microorganisms witch enhance our immunity, improve our ability to digest food, increase our ability to cope with stress and enhance our overall health. While at the same time, there are pathogens and unfavorable microorganisms which have the potential to severely disrupt immune function, alter our state of well-being and cause long term health issues [3].

Some clues from germ free animals
Studies on mice and guinea pigs have demonstrated that germ free animals are significantly more susceptible to infection by certain bacteria, viruses and parasites [4, 5, 6].

Section Summary

This section provided a brief introduction to the importance of a the microbiota in health and disease. Key points include:

  1. The intestinal microbiota composition has a direct influence on our immune system and our susceptibility to chronic disease
  2. A beneficial microbiota composition can improve immune function, increase ability to cope with stress and enhance overall health
  3. Unfavorable shifts in the microbiota can result in immune instability, chronic disease and various health issues
  4. Studies from germ free animals demonstrate that a diverse microbiota is an integral part of immune stability


  1. June L Round, Sarkis K Mazmanian "The gut microbiota shapes intestinal immune responses during health and disease." Nature reviews. Immunology 9.5 (2009): 313-23. PubMed
  2. Kirsty Brown, Daniella DeCoffe, Erin Molcan, Deanna L Gibson "Diet-induced dysbiosis of the intestinal microbiota and the effects on immunity and disease." Nutrients 4.8 (2012): 1095-119. PubMed
  3. Calum J Walsh, Caitriona M Guinane, Paul W O'Toole, Paul D Cotter "Beneficial modulation of the gut microbiota." FEBS letters 588.22 (2014): 4120-30. PubMed
  4. H SPRINZ, D W KUNDEL, G J DAMMIN, R E HOROWITZ, H SCHNEIDER, S B FORMAL "The response of the germfree guinea pig to oral bacterial challenge with Escherichia coli and Shigella flexneri." The American journal of pathology 39 (1962): 681-95. PubMed
  5. H Inagaki, T Suzuki, K Nomoto, Y Yoshikai "Increased susceptibility to primary infection with Listeria monocytogenes in germfree mice may be due to lack of accumulation of L-selectin+ CD44+ T cells in sites of inflammation." Infection and immunity 64.8 (1996): 3280-7. PubMed
  6. R M Nardi, M E Silva, E C Vieira, E A Bambirra, J R Nicoli "Intragastric infection of germfree and conventional mice with Salmonella typhimurium." Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas 22.11 (1990): 1389-92. PubMed
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About Michael Anders

After being affected by seborrheic dermatitis, I have made it my goal to gather and organize all the information that has helped me in my journey.

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