Ask the Doctor: Question: I have a hard time sleeping & have some mild anxiety. I heard magnesium might help… is that true? Magnesium is the fourth abundant mineral in the body –  half found in the bones and the other half inside body tissues and organs – and is needed for over 300 biochemical reactions. Some of these reactions include: enzymes activation, normal heart and nerve function, keeping the heart pumping strong and steady, regulate calcium levels, plus other important nutrients in the body like copper, zinc, potassium, vitamin D. Those are some of the big jobs; however, magnesium plays some other key roles in immune function, diabetes, and blood…