Calcium: Calcium is the most abundant mineral in the body. It is essential for the development and maintenance of strong bones and teeth; roughly 99% of calcium in the body is deposited in these two places. Calcium also helps the heart, nerves, muscles, and other body systems work properly. To function correctly, calcium must be accompanied by several other nutrients including magnesium, phosphorous, and vitamins A, C, D, and K.

The best source of calcium is from food, but supplements may be necessary for those who cannot meet their calcium needs through diet alone. In fact, according to the National Institutes of Health, many Americans consume less than half the amount of calcium recommended to build and maintain healthy bones. Heavy use of caffeine can diminish calcium levels; therefore, higher amounts of calcium may be needed if you drink a lot of coffee. Also, a diet high in protein can increase loss of calcium through the urine. Excessive intake of sodium, phosphates (from carbonated beverages) and alcohol, as well as the use of aluminum-containing antacids also contribute to increased excretion of calcium.

Calcium deficiency can be found in people with malabsorption problems, such as Crohn's disease, celiac disease, and surgical intestinal resection. Prolonged bed rest causes loss of calcium from the bones and the elderly are less able to absorb calcium.

Symptoms of calcium deficiency include muscle spasm or cramping, typically in hands or feet; hair loss (alopecia); dry skin and nails which may also become misshapen; numbness, tingling, or burning sensation around the mouth and fingers; nausea and vomiting; headaches; yeast infections (candidiasis); anxiety; convulsions/seizures; and poor tooth and bone development.

Foods containing the highest level of calcium are collard green, black strap molasses and broccoli.