What was the key element in human evolution? The key chemical substance that contributed to the evolution of the human brain is vitamin B12, scientifically known as cyanocobalamin. It is an aminoacid of the B complex which plays a key role in the DNA synthesis and the myelination of axons, which is the long nerve cell process that transmits nerve impulses from the cell body to another neuron via the synaptic gap. Myelin is the fatty sheath that covers, protects, and feeds the axon. Another function of the myelin sheath is to increase the speed at which impulses travels along the myelinated fiber (a bundle of axons). Aside from contributing to the maintenance of the axon myelin sheath, vitamin B12 also plays a role in the production of red blood cells, since its deficiency causes pernicious anemia.
But why was it important for the human brain evolution? Because it is found in great amount in meat, dairy, and other animal products, such as liver and bone marrow, and it was the dietary change of man's first direct ancestor, Homo erectus, that started up the central nervous system evolution, when he began feeding almost entirely on animal bone marrow, entrails, and meat as he ventured out of the African continent into the unknown. Stereoscopic vision and the stimulation of cortical motor areas in the frontal lobe of the brain by the use of hands, in manufacturing and wielding weapons, and tongue and lips to produce intelligible speech, had to be sustained by concentrated calories and vitamin B12, which are plentifully-contained in animal fat and meat.