Gastroenterology / Neurology

Dysbiosis and Autoimmune Diseases

August 26, 2016
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By Joseph E. Scherger, MD, MPH
Vice President, Primary Care, Eisenhower Medical Center; Clinical Professor, Keck School of Medicine, University of Southern California

SYNOPSIS: This study adds to mounting evidence indicating that dysbiosis and imbalance in the gut microbiome are linked to autoimmune diseases like multiple sclerosis.

SOURCE: Glenn JD, Mowry EM. Emerging concepts on the gut microbiome and multiple sclerosis. J Interferon Cytokine Res 2016;36:347-357.

A recent review conducted by scientists from Johns Hopkins University School of Medicine’s Department of Neurology focused on the human gut biome and its complex interactions with the immunology of the human body. The scientists had a suspicion that imbalance of the gut microbiome was related to increased incidence of autoimmune disease.

The human gut actually has the highest recorded bacterial density of any ecosystem. Even more astounding is the gut’s concentration of viruses, which far outnumber the microbiome’s bacterial organisms. Of central importance to the study of the microbiome are the viral bacteriophages that inhabit the gut, infecting bacteria and facilitating DNA exchange.

Developed at birth, the normality of the microbiome is improved by vaginal delivery and breast feeding. Children whom were born by C-section or who did not breastfeed have demonstrated delayed microbiome development. This tends to normalize by age seven. Patients suffering from multiple sclerosis were more likely to be born during a C-section and had shorter durations of breastfeeding on average.

Researchers are seeing evidence pile up, suggesting that not just dysbiosis but a variety of gut biome disorders can lay the groundwork for the development of autoimmune disease. There is especially strong evidence for dysbiosis’s causal relationship with two autoimmune diseases: Crohn’s Disease and multiple sclerosis. As such, modern Western diets, adopted in the years since the Second World War, may be to blame for the increase in incidence of autoimmune diseases, as the Western diet is high in unhealthy trans fats, sugar, and inflammatory proteins, which have been associated with dysbiosis.