Our bodies are teaming with single-celled organisms called microbes, which include bacteria as well as archaea, fungi, viruses, and others. In fact, the number of microscopic inhabitants is roughly equivalent to the number of our own human cells. There are distinct, diverse microbial communities – or microbiomes – found in various parts of the body, including the skin, mouth, lungs, and the gut.
These complex communities help us digest food and extract nutrients, carry out certain metabolic processes, and work in tandem with our immune system to protect the body against infectious agents
Just as we provide these microorganisms with a warm, comfortable environment and plenty to eat, their presence plays a critical role in our health. These complex communities help us digest food and extract nutrients, carry out certain metabolic processes, and work in tandem with our immune system to protect the body against infectious agents. When an imbalance in their delicate ecosystem occurs, it can have serious effects on our health.
Many chronic illnesses, including obesity, type 2 diabetes, and inflammatory bowel disease, appear to be affected by the microbiome. The relationship between autoimmunity and the microbiome is still being studied intensely, but it is likely that these conditions are associated with an imbalance in the gut microbiome.
Although strong evidence is lacking, there seems to be a marked reduction in diversity of the gut microbiome amongst autoimmune disease patients. In Crohn’s Disease, one study has revealed that a bacteria called Faecalibacterium prausnitzii, which is normally found in healthy individuals, was missing in Crohn’s patients. Researchers have made similar connections in other inflammatory bowel diseases, like Ulcerative Colitis. While these studies do not indelibly prove the connection of the microbiome to the pathophysiology of autoimmune disease, they certainly signal the need for further investigation.
To discover the complex role of the microbiome in health and disease, a growing body of research is focused on characterizing the human microbiome. One such endeavor is The Human Microbiome Project (HMP), an interdisciplinary effort by NIH to collect resources for characterizing microbial communities found in the gastrointestinal tract, nasal passages, oral cavities, skin, and the urogenital tract.
The data collected by the Human Microbiome Project is enabling researchers to study disease, diversity, biogeography, and molecular function as it relates to the human microbiome. This information – as well as other innovative microbiome research – will continue to serve as a blueprint for understanding the symbiotic relationship between microbes and the host, and the impact it can have on human health and disease.
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