The Short Version
The literature strongly supports that stress can impair the intestinal barrier by altering tight-junction function and increasing permeability. Reviews, animal studies, and cell studies also link this barrier disruption to greater passage of luminal antigens and, in some models, bacteria. The main caveat is that the full causal chain is demonstrated most directly in animal and in vitro research; human evidence is stronger for permeability changes than for direct bacterial translocation.