Magnesium is an essential dietary mineral, and the second most prevalent electrolyte in the human body. A deficiency increases blood pressure, reduces glucose tolerance and causes neural excitation.Magnesium deficiencies are common in the western diet because grains are poor sources of magnesium. Other prominent sources of magnesium, like nuts and leafy vegetables, are not eaten as often. It is possible to fix a magnesium deficiency through dietary changes. If magnesium is supplemented to attenuate a deficiency, it acts as a sedative, reducing blood pressure and improving insulin sensitivity.Maintaining healthy magnesium levels is also associated with a protective effect against depression and attention deficit hyperactivity disorder.The intestinal absorption of magnesium varies depending on how much magnesium the body needs, so there are not very many side-effects associated with supplementation. If there is too much magnesium, the body will only absorb as much as it needs.