In the period from 2015 to 2025, we carried out a set of studies in areas of active geophagy among wild and domestic animals in different regions of Russia as part of testing the “rare earth hypothesis of geophagy”. Based on the data obtained and the analysis of published information on geophagy, which is common among animals and humans in different regions of the world, as well as the analysis of cases of diseases registered in areas of active geophagy in animals and humans caused by both excessive and abnormally low content of rare earth elements in soils, vegetation and drinking water, a hypothesis was proposed about the special role of rare earth elements in the neuroimmunoendocrine system in the body of mammals. From the standpoint of this hypothesis, geophagy should be considered as a universal evolutionarily conditioned way of maintaining the balance of rare earth elements in the neuroimmunoendocrine system, which in turn ensures the balance of chemical elements throughout the body.
Аlexander М. Panichev (Thu,) studied this question.