This document provides information about magnesium, including: - Magnesium is essential for good health and is the 4th most abundant mineral in the body, with half located in bones. - Magnesium aids muscle and nerve function, keeps heart rhythm steady, boosts immune system, and is removed from the body via kidneys. - Good dietary sources include nuts, beans, grains, dairy, spinach and other greens, potatoes, bananas, and raisins. - Recommended daily intake varies depending on age and sex. - Magnesium helps control blood pressure and blood sugar levels, and may lower risk of heart disease and increase exercise time.