Geophagy, Rare Earth Elements and Geochemical Endemics

The analysis of published data on geophagy in humans, including manifestations of its variant known as “pica”, as well as information on geochemical endemics associated with geophagy and rare earth elements, together with our own research experience, allows us to conclude that geophagy in humans, as well as in animals, is primarily a natural, evolutionarily determined form of maintaining the necessary balance of rare earth elements in the neuroimmunoendocrine system. Disturbances in the composition and concentration of necessary rare earth elements (REE) in the structures of the most important protective and controlling system in the mammalian organism lead to disorders of mineral and general metabolism in the body and, as a result, to geochemical endemics. Geochemical endemics occur in landscapes with anomalous levels of biologically available REE forms, i.e., levels that differ significantly both towards deficiency and towards exceeding background levels. The imbalance in the metabolism of other chemical elements in the body seems to have a subordinate importance in the mechanism of occurrence of geochemical endemics in relation to REE.