Causes for concern are both an overgrowth of microorganisms that are normally present in the intestines and the presence of microorganisms that are not normally present in the intestines. Either condition signals that major physiological pathways in the intestinal environment are outside homeostatic limits. Some of the immediate consequences can include adverse alterations in pH, digestion, and absorption. These factors set the stage for further deviations from health, including the retention and proliferation of microorganisms that would be maintained ordinarily at a lower concentration, or would be rapidly expelled. Such conditions can produce anatomic disruption of the intestinal mucosa resulting from the physical infestation of the microorganism, and chemical insult and physiological upset of the mucosa caused by adverse reactions to the metabolic products of the invader. Maldigestion and malabsorption of nutrients can produce longer-term dysfunction of the host. This condition can persist subclinically for years, even decades. By the time signs and symptoms become evident, the patient might be suffering severe and extensive underlying pathophysiology.
Even more ominous than a primary infestation is the tendency of invading microorganisms to metamorphosize into various stages, and to migrate to tissues and organs sometimes distant from the gastrointestinal tract. Such stages, including cysts, can remain dormant within tissues, and can be extremely difficult to detect. Discouragingly, the level of difficulty of detection is often directly proportional to the level of difficulty of treatment. These factors underscore the importance of maintaining constant vigilance in controlling the intestinal environment.
Secondary infections, often involving so-called “opportunistic” organisms, can provide evidence of a more deeply rooted, insidious process. One such organism is the yeast Candida albicans, which is implicated in a variety of disorders and has a predilection for virtually any mucous membrane. Often innocuously present in small amounts, it is important not only to control its concentration, but also to correct the causes and the effects of its proliferation.