Alessio Fasano, M.D., Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children, Harvard Medical School, Boston

The gut microbiome consists of more than 100 trillion microorganisms, most of which are bacteria. It has been just recently recognized that there is a close bidirectional interaction between the gut microbiome and our immune system. Increased hygiene and a lack of exposure to various microorganisms have been held responsible for the "epidemic" of chronic inflammatory diseases over the past 30–40 years in industrialized countries.

While factors such as modality of delivery, neonatal feeding regimens, use of antibiotics, and infections can influence microbiota composition, diet is by far the most important variable affecting gut ecosystem. Dr. Fasano will discuss how the gut microbiome affects health and the steps that can be taken to keepthe microbiome healthy.