The Long Arm of the Very Small: Human Microbiome and Disease

It is a well-known fact that we share our body with a large number of prokaryotic cells and viruses that reside on all surfaces of our body and make up what is nowadays mostly referred to as the human microbiota. An estimate of cell numbers puts the ratio prokaryotic to eukaryotic cell count to 10:1 and the size of the microbial genome to 100 times the size of the human genome. While it is in some respect accepted and expected that the presence of the microbiota has a direct effect on the organ in which it resides, it is becoming increasingly evident that they can affect far organs with devastating metabolic and physiological effects on the host. This mini review highlights recent research exploring the impact of the microbiome on far organs and host metabolism.