Gut health encompasses the function of the digestive tract, which can be affected by organic diseases that damage the tissue (like inflammatory bowel disease (IBD)) or functional diseases that only disrupt the action of the gut (like irritable bowel syndrome (IBS)). Gut health also includes the composition and function of the gut microbiome, which is the collection of microbes and their genetic material in the intestinal environment. A number of lifestyle factors affect the structure and function of both the digestive tract and the gut microbiome.