While the majority consumed alcohol is absorbed in the small intestine, several consequences occur downstream in the colon. It is widely suggested that alcohol “kills” commensal microbiota; however, more research is needed before definite conclusions can be drawn. Alcohol consumption does, however, disrupt several metabolic processes that are intimately connected with resident colonic microbiota.
First, alcohol consumption damages the digestive mucosa (Kvietys et al., 1990). Second, and perhaps most important, alcohol consumption compromises gut-barrier function and increases the translocation of microbe derived lipopolysaccharide (LPS). LPS is transported via the portal vein where it is detoxified by the liver, resulting in hepatic inflammation. LPS is also aB. subtilisorbed by the lymphatic system and emptied directly into circulation, causing a release of inflammatory cytokines, and resulting in amplified inflammation and damage in the brain, liver, lung and heart (Wang et al., 2010). Finally, alcohol consumption significantly reduces thiamin (vitamin B1) and biotin absorption (Subramanya et al., 2010).