Figure 2.

A super-organismal view of the human microbiome. Core and variable components of the human microbiome could have important implications for human health, including nutrient responsiveness, innate and adaptive immunity, and development. As the microbiome affects multiple aspects of human health and disease, host biology influences the composition and function of the commensal microbiota. A subset of microbial genes may be found in most healthy human beings (core microbiome), whereas variable components are present only in specific ethnic groups, age groups, geographic locations, or associated with specific dietary patterns or disease states. Manipulation of either the core or the variable parts of the human microbiome can affect human physiology, overall health status, and disease susceptibilities. Adapted with permission from Macmillan Publishers Ltd: Nature,¹ copyright 2007. http://www.nature.com/nature/.