<P> The relationship between some gut flora and humans is not merely commensal ( a non-harmful coexistence ) , but rather a mutualistic relationship . Some human gut microorganisms benefit the host by fermenting dietary fiber into short - chain fatty acids ( SCFAs ) , such as acetic acid and butyric acid , which are then absorbed by the host . Intestinal bacteria also play a role in synthesizing vitamin B and vitamin K as well as metabolizing bile acids , sterols , and xenobiotics . The systemic importance of the SCFAs and other compounds they produce are like hormones and the gut flora itself appears to function like an endocrine organ , and dysregulation of the gut flora has been correlated with a host of inflammatory and autoimmune conditions . </P>
what is the role of the gut flora
by fermenting dietary fiber into short - chain fatty acids ( SCFAs ) , such as acetic acid and butyric acid , which are then absorbed by the host synthesizing vitamin B and vitamin K as well as metabolizing bile acids , sterols , and xenobiotics to function like an endocrine organ