Analysis of elements in feces provides indirect information about the potential for toxic metal burden. For many toxic metals, fecal (biliary) excretion is the primary natural route of elimination from the body. Fecal elemental analysis also provides a direct indication of dietary exposure to toxic metals. Specimen collection is convenient for the patient and only requires a single-step procedure.
Analysis of elements in feces provides a comprehensive evaluation of environmental exposure, potential for accumulation in the body (Hg), and possibly endogenous detoxification of potentially toxic metals. For many toxic elements such as mercury, cadmium, lead, antimony and uranium, biliary excretion into the feces is the primary natural route of elimination from the body. The primary process by which the body eliminates the insidious sulfhydryl reactive metals is through the formation of metal-glutathione complexes, of which greater than 90% are excreted into the bile. Evidence for the extent of exposure to mercury from dental amalgams is provided by the fact that fecal mercury levels are highly correlated with the number of amalgams in the mouth. It also clear that fecal mercury levels for people with dental amalgams are remarkably similar from day to day, and approximately ten times higher than in people who do not have mercury amalgams.
A primary objective of preventive medicine is avoidance or removal of exposure to toxic substances. The rate of oral absorption of toxic metals varies considerably among elements, and among subspecies of a particular element. Fecal elemental analysis can provide a direct indication of dietary exposure.