Macrominerals (major minerals) are required in amounts greater than 100 mg/day. They include calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), potassium (K), chloride (Cl), and sulfur (S). In contrast, trace minerals (microminerals) are needed in amounts less than 100 mg/day and include iron, zinc, copper, iodine, selenium, and manganese.