If the bad bacteria in the gut are left in check, it can lead to a condition called Leaky Gut Syndrome. Young dogs are more susceptible to this condition, as are dogs fed dairy products. In this condition, the intestinal barrier can become compromised and the permeability is increased. Small openings can develop in the lining of the intestine, which allow large molecules of undigested or incompletely digested foods to enter the bloodstream.
The liver is the main organ inside the body whose function is to process substances which are “foreign” to the body and to make them “friendly”. If the quantity of incompletely digested foods which enters the bloodstream is too great for the liver to clear almost immediately, the immune system then recognizes these molecules as being foreign to the body and produces antibodies against them. When the food is eaten again and again and passes into the bloodstream undigested or only partially digested, the antibodies bind with the food. These antibody-food complexes can travel through the bloodstream to any part of the body where they then cause problems. The allergy and immune systems will continue unchecked.