Brain function is impacted by a variety of factors, including hydration and electrolyte balance. Adequate intake of water, sodium, potassium, and magnesium is important for nerve cells to function properly. Ingesting omega-3s, EPAs, phosphatidylserine, and choline can also support brain function to some degree. Inhaling through the nose has been shown to improve memory retrieval, memory formation, and some aspects of cognition. The olfactory system is the most ancient sensory system and inhalation activates certain regions of the neocortex, increasing the activity of brain areas such as the hippocampus. Fat is also important for brain function, as nerve cells and other cells in the brain have an external layer made up of structural fat. The fat that makes up those neurons and other nerve cells is different than the other types of fat in the body, and maintaining the health of those neurons comes from the foods we eat, such as essential fatty acids and phospholipids.