Most calcium is found in teeth and bones, but it also is needed for blood clotting, nerve cell communication, and muscle movement. Calcium deficiencies are often associated with Vitamin D deficiencies. Other commonly deficient groups include vegans, dark skinned ethnicities, and people who stay indoors most of the time. Older women also often have calcium deficiencies, though whether this is the cause or effect of osteoporosis is uncertain.
Calcium absorbs best when taken with Vitamin D .
In spite of the popularity of calcium-fortified orange juices, Vitamin C actually appears to inhibit calcium absorption. Calcium may reduce the body's absorption of Magnesium and Zinc . Since both of these nutrients are also important in the prevention of osteoporosis , supplementation may be necessary. 1 Calcium is useful in general for gum and tooth care. Individuals with gingivitis who take calcium supplements for six months show a marked improvement.