The gut is a major, potential portal of entry into the body for foreign antigens. Only its intact mucosal barrier protects the body from foreign antigen entry and systemic exposure.
This mucosal barrier is made up of non-immunological components (mucous coat, mucous membranes) working independently and in concert with the local mucosal immune system (secretory IgA, lymphoid elements in Peyer’s patches). Its effective functioning is peripherally assisted by a competent immune system (especially IgA production, RES function), specific hepatobiliary functions (Kupffer cell activation/phagocytosis, hepatocyte function, bile production and elimination), a healthy/balanced population of host-friendly microflora (roughly a 20-40/60-80 ratio of Gram negative to Gram positive with sufficient percent of Lactobacillus species), and optimal digestive processes (adequate HCI/pepsin and pancreatic digestive enzyme activity, optimal soluble fiber intake, low transit time).