Role: Structural material for bones and teeth. Involved in regulating nerve conduction, blood clotting, membrane permeability, nerve irritability, and muscle contraction.
Deficiency: Slow, stunted growth; osteoporosis (bone loss) with dowager’s hump, bone fractures, bone pain. Tooth loss. Muscle cramping.
Sources: Milk, cheese, yogurt, ice cream; canned fishes with bones; tofu made with calcium carbonate; fortified fruit juices, broccoli, kale, almonds.
Toxicity: May interfere with absorption of iron, zinc, magnesium, and other minerals. May cause kidney stones; may be constipating.
Very high blood calcium levels cause coma and cardiac arrest.