overview:
• Magnesium is the second most abundant cation after potassium.
60% is found in the bone, 25% in muscle and the remainder in soft tissues and fluids (especially gastric juice).
• In the muscle tissue the majority of magnesium is found in the mitochondria, the organelles that are responsible for oxidative phosphorylation and producing ATP.

function:
• Magnesium regulates the absorption of calcium and is involved in the structural integrity of bones and teeth. If it is deficient in the bones, the bones may be dense but have poor trabecular integrity and thus be brittle. In both Finland and the Netherlands, there is a high ratio of calcium to magnesium intake (4 to 1) and the rate of osteoporosis is the highest in the world.
• Magnesium regulates the contractility of the heart muscle. It is concentrated 18x greater in the heart muscle than in the bloodstream. A decreased magnesium level in the heart muscle may predispose a person to coronary spasms. In areas where there is harder water (mainly due to magnesium), there is a much lower rate of heart disease.
• Magnesium has a relaxing effect on smooth muscle. It may be helpful in relaxing the smooth muscle of the bronchioles (improving asthma) and the arterioles (lowering blood pressure).