The role of selenium in human evolution

Human migration around the world has resulted in habitation of environments that differ widely in their soil selenium (Se) levels. Consequently, populations around the world have widely different dietary intakes of this essential micronutrient. Localized adaptation to dietary differences has occurred in genes that process macronutrients, such as lactose and starch, as well as micronutrients, such as Se, iron and iodine. Recent evidence indicates that local adaptation to dietary Se intake has occurred in genes that incorporate Se into selenoproteins and regulate the use of this micronutrient. The genetic adaptation signal is particularly strong in populations that live in the Se-deficient regions of China, suggesting that Se homeostasis has been important during recent human evolution and that changes in the use and regulation of this element may have helped humans to inhabit environments that contain an inadequate supply of dietary Se.