Rare Earth Elements: Review of Medical and Biological Properties and Their Abundance in the Rock Materials and Mineralized Spring Waters in the Context of Animal and Human Geophagia Reasons Evaluation

New data on the abundance of rare earth elements (REE) and their biological properties, which appeared in recent decades, force the researchers to reconsider the facts previously collected by different researchers related to the study of the geophagia phenomenon in animals and humans. From the standpoint of the new data it becomes apparent that one of the reasons for instinctively traditional form of geophagia, as well as for drinking water from mineralized sources by animals and a man with lengthy visits to the same places could be an instinctual drive of a specific organism to adjust in their bodies and tissues the concentration and ratio of the rare earth elements which are able to actively influence, either directly or indirectly (through the effects on metabolism of other chemical elements in the body) the biochemical and physiological processes that determine the quality of health. Since REE influence at the level of nerve tissue biochemistry, hormonal regulation of the body and even at the genetic level, it all can point to a higher order which they occupy in the hierarchy of elements in the composition of any organism. It seems that REE have reasons to claim to be the main causes of all instinctive forms of traditional geophagia and related consumption of mineralized water.