Magnesium is a vital catalyst in enzyme activity, especially the activity of those enzymes involved in energy production.  It assists in calcium and potassium uptake.  A deficiency of magnesium interferes with the transmission of nerve and muscle impulses, causing irritability and nervousness.  Supplementing the diet with magnesium can help prevent depression, dizziness, muscle weakness, twitching, and PMS.  It also aids in maintaining the body’s proper pH balance.