Probiotics: A Clinical Guide

Martin H. Floch, MD; Adam S. Kim, MD

Chapter 3: Barrier Function And Theimmune Response (continued)

Karen L. Madsen, PhD

The ability of the intestinal tract to act as a barrier between the external environment and the closely regulated internal milieu is absolutely essential for human health. In our evolution as vertebrates, we have developed elegant mechanisms to coexist with bacteria. Colonization of the intestine with bacteria begins during the birth process, and within several months a relatively stable bacterial population resides in our intestines. Although humans are highly adapted to coexisting with bacteria, confining their existence to the lumen of the GI tract and restricting immune responses to the…