The role of diet and physical activity in influencing the microbiota/microbiome

Lifestyle factors account for the vast majority of attributable risks in chronic diseases ranging from type II diabetes mellitus ( Chapter 7 ), cardiovascular diseases ( Chapter 8 ), cancers of various anatomic sites ( Chapter 9 ), and mental health outcomes such as depression ( Chapter 11 ). Over the last decade research related to the microbiota/microbiome has proliferated, largely centering on its impact on health and disease processes. We now know that the microbiota exert influence beyond their capacity to aid in the digestion of food in the gastrointestinal tract (GI). Indeed, these microorganisms have been implicated in virtually every chronic disease process. Research now underway may lead to identifying the bacterial populations that may be driving chronic disease processes, thus paving the way for viable therapeutic targets. Thus, it is no surprise that these efforts have included research to understand the impact of lifestyle factors on microbial composition and function. As noted in Chapters 1 and 2 Chapter 1 Chapter 2 , virtually all the raw materials for biological processes come from the diet, and the digestive tract is the most intimate place of contact. So, it is not surprising that a strong base of evidence shows that diet is the most influential lifestyle factor on gut microbiota, with changes occurring rapidly (i.e., within days). Both reflecting and driving interest in this arena, there is a plethora of research studies devoted to the impact of diet, ranging from single nutrients to complete and often complex dietary patterns, regarding the gastrointestinal, especially colonic, environment. Physical activity also is known to impact the microbiota; studies have examined different exercise modalities for their influence on gut microbiota. This chapter is focused on the examination of the current state of the literature regarding the impact of lifestyle factors, namely diet and physical activity, on gut microbial composition and function, and consequential impact on chronic disease risk.