Micronutrients and the evolution of the human brain

Abstract

Several theories describe the increasing enlargement of the human brain because of environmental changes or dietary alterations. The environmental changes led to a change in diet quality (micronutrient density) because of changes in food foraging, which ensured that a growing brain was adequately supplied with energy and essential micronutrients for growth. The hippocampus is a direct link between nutrition and the environment, which is necessary for adapting to a changing climate. The adaptation then improves foraging success and enables better food quality and thus favors the development of the hippocampus, which in turn influences the development of other brain regions.

The extraordinary ability of our ancestors for persistent running not only favored hunting but also had direct effects on hormones that support brain development. The connection between physical exercise, nutrition, and plasticity of the hippocampus and the resulting adaptation to changing environmental conditions is essential for triggering or stimulating brain development. As the variability selection hypothesis proposes, fluctuations in environmental conditions need a short adaptive answer, which may become genetically fixed and selected. The presented hypothesis allows a meaningful combination of the different theories of brain development (pulse climate, variability selection, amplifier lakes) and nutrition theories (aquatic, cooking, energy).

The assumption that the hippocampus, as a “central sensory organ”, detects new events and enables an adaptive response is not an isolated assumption for the hippocampus since other brain regions can also react similarly with synaptic plasticity. Through adult hippocampal neurogenesis (AHN), which is unique only in the hippocampus and synaptic plasticity, there is the possibility of detection and (neurological) storage of previously unknown events and linking them to other cortical areas, which may increase cortical volume.