According to the consensus, the change in the environment has increased the brain volume. However, this change not only means a change in flora and fauna but also living conditions: unknown food, environment, and risks. All challenges that the brain must handle. If the brain grows due to a change in the environment and an improvement in the quality of nutrition, then the question arises as to how this growth in the brain is triggered. The brain consists of gray matter (neurons) and white matter (connections between neurons). In principle, the number of neurons does not change once the brain is fully developed, with one crucial exception: the hippocampus. The hippocampus is a small region in the center of the brain that is one of the older regions in evolutionary terms. In the hippocampus, new messages (from all the sensory organs) are received, processed, partially stored, or connected to other brain areas. The hippocampus reacts to environmental challenges (spatial orientation, stress, fear, and hunger), thus representing an essential link to the environment. To ensure this link to the environment, new neurons in response to external events are created in the hippocampus throughout life, which then connect with synapses and thus form new networks. The brain regions connected to the hippocampus could increase in volume through the constant flow of new experiences from the environment to store this data and to be able to retrieve it in the context of new experiences from the so-called episodic memory and further brain areas. However, such growth requires that the brain receives the energy it needs and all micronutrients permanently and in sufficient amounts. The hippocampus needs a variety of micronutrients (vitamin D, vitamin A, iron, and zinc, among others) to ensure neurogenesis and function.