Dietary clay in the chemoprevention of aflatoxin-induced disease

Aflatoxins are harmful by-products of mold growth and, though invisible to the naked eye, are potentially fatal. The aflatoxin problem is long-standin g and inextricable. Concerns about the aflatoxins originate from the strong implications of their involvement in disease and death in humans and anima ls, yet scientists and clinicians are still seeking ways to effectively dea l with these dangerous and elusive chemicals. Safe, practical, and effectiv e strategies for the detoxification of aflatoxin-contaminated food and feed are highly desirable. A simple and effective approach to the chemopreventi on of aflatoxicosis has been to diminish or block exposure to aflatoxins vi a the inclusion of HSCAS clay in the diet. HSCAS clay acts as an a aflatoxi n enterosorbent that tightly and selectively binds these poisons in the gas trointestinal tract of animals, decreasing their bioavailability and associ ated toxicities, Further studies to delineate the molecular mechanisms of a ction have shown that the dicarbonyl system of aflatoxin is essential for t ight binding by HSCAS. In these studies, adsorption data was fitted to mult iple isotherm equations including the Langmuir, multi-langmuir, general Fre undlich, Langmuir-Freundlich, Toth and various transforms. Information deri ved included: the Gibbs standard free energy change of adsorption, enthalpy of adsorption, capacity, affinity, and heterogeneity coefficient. Computer modeling was also utilized to provide additional structural information an d insight into the mechanism. Evidence suggests that aflatoxins may react a t multiple sites on HSCAS particles, especially the interlayer region, but also at edges and basal surfaces. Since clay and zeolitic minerals comprise a broad family of functionally diverse chemicals, there may be significant hidden risks associated with their indiscriminate inclusion in the diet, A ll aflatoxin binding agents should be rigorously tested, paying particular attention to their effectiveness and safety in aflatoxin-sensitive animals and their potential for interactions with critical nutrients.