> Magnesium is a must. The diets of all Americans are likely to be deficient. Even a mild deficiency causes sensitiveness to noise, nervousness, irritability, mental depression, confusion, twitching, trembling, apprehension, insomnia, muscle weakness and cramps in the toes, feet, legs, or fingers. Folic acid deficiency can lead to neural tube closure defects (NTDs) and anemia. Zinc deficiency affects immune function, contributing to as many as 800,000 child deaths per year. Iodine deficiency is the leading preventable cause of brain damage and it can significantly lower the IQ of whole populations. >