It is common knowledge that calcium plays a vital role in bone health, but the mechanisms that use calcium at a cellular level are not as well known. In addition to helping bones stay hard and strong, the skeletal system serves as a backup calcium storage area in case calcium blood levels dip too low. People need calcium throughout their entire lives to maintain a healthy skeletal system.
During bone growth, calcium is absorbed by the gastrointestinal system and is deposited on the surface of the bone. The calcium bonds to the organic surface of new bone cells and hardens them. These hard layers of bone material and calcium are what make the skeletal system strong. Some of the minerals in bone are calcium phosphate, calcium fluoride and calcium carbonate. This combination of minerals helps keep bones from breaking under crushing force.
Bone growth is a process that continues throughout the lifetime. Calcium is a vital mineral in the bone growth process. During bone growth, cells called osteoclasts digest old, weak bone cells that have less calcium than when they were new. For new bone to form, vitamin D stimulates cells called osteoblasts. The osteoblasts utilize calcium to create new layers of bone cells to replace the ones destroyed by the osteoclasts.
When osteoclasts destroy old bone cells, the residual calcium in those cells is released into the bloodstream. Early in life, dietary calcium intake is especially important because it helps to build valuable calcium stores in the skeletal system. In older adults, the intestinal system absorbs less calcium from food. This forces the body to utilize calcium stores from the skeletal system to maintain adequate blood calcium levels. The skeletal system will become brittle and weak if too much calcium leaches from the bones, so consuming adequate calcium early in life is imperative for bone health later in life.
Sources of Calcium
Calcium cannot be generated by the human body, so it must come from outside sources such as food or dietary supplements. Always speak with your doctor before changing your calcium intake regime. Calcium can be found in dairy foods, dark green, leafy vegetables, nuts and calcium fortified foods. Some examples of foods that contain calcium are milk, cheese, yogurt, bok choy, broccoli and almonds. Foods that are commonly fortified with calcium in the U.S. are orange juice, cereal, bread, soy beverages and tofu products.
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- Centers for Disease Control and Prevention: Calcium and Bone Health
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