Effects of coffee on gut microbiota in health and diseases

Growing evidence obtained in the human and animal studies suggests that coffee has modulating impacts on gut microbiota. Majority of the studies found that moderate consumption of coffee may increase the relative abundance of beneficial bacteria such as Firmicutes, Actinobacteria and Bifidobacterium spp and decrease the abundance of Enterobacteria and Bacteroidetes. Coffee consumption is reported to increase gut microbiota diversity. Coffee is also known to impact some gastrointestinal functions such as motility, secretion, absorption, and immune response. Some of the coffee effects on gastrointestinal functions may partly be through its effects on microbiota. In this chapter, we will look closely into the specific effects of coffee on gut microbiota composition, diversity, and growth. We will also review the effects of coffee on selected gastrointestinal functions in health and diseases and discuss whether gut microbiota has a role in these coffee-associated functional changes in the gastrointestinal tract.