Role: Structural material for bones and teeth. Component of nucleic acids, of phospholipids, of numerous enzymes, and of high-energy compounds such as ATP.
Deficiency: Weakness, muscle loss, bone loss and pain, anorexia. (Rare. Most likely in people taking phosphorus-binding drugs.)
Sources: Protein-rich foods. Cereal grains. Soft drinks. Present in most foods
Toxicity: Contributor to osteoporosis. Lowers blood calcium levels. Severe calcium depletion causes convulsions, muscle spasms.