It seems that calcium is being added to everything these days, from orange juice to cereal bars. Why this explosion of calcium-fortified foods? Osteoporosis is a major concern in the medical field for older people. As well as the loss of strength in the bones related to the condition, many bone fracture cases are due to osteoporosis. There is some concern, however, that too much calcium might be harmful to the body.
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Bone is actually living tissue that constantly changes and responds to what we do to our bodies. The matrix of bone consists of collagen and calcium phosphate, which hardens and provides the framework for the bone itself. In fact, our bones contain 99 percent of the body’s calcium. Bone formation is highest during childhood and through the teenage years, but peaks by about 30 years of age.
The role of calcium
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After age 30, bones are all about maintenance and calcium is a major factor in this. Calcium is stored in the bones. It is also needed for nervous system functioning and muscle contraction whether you are lifting a dumbbell or the remote. Our supply of calcium is obtained through our dietary intake which enters the blood stream via absorption in the intestines. An increase in the amount of calcium ions in the blood triggers the release of a specific hormone called calcitonin, which then signals the bone to take up the calcium and create new bone. When the levels of calcium in the blood decrease, the calcitonin release stops. When calcium levels in the blood are low, another hormone causes the bone to release calcium into the blood. Since calcium is needed in the body for many processes, the bone will continue to release the mineral and eventually result in bone loss.
Who is at risk?
Those with the highest risk for osteoporosis are women of small stature, especially those with a family history. Risk also increases with age. Factors that compound the risk for osteoporosis in any individual are smoking, alcohol use, low physical activity, a vitamin D and calcium-deficient diet, low hormone levels and eating disorders.
Recommended daily intake
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To reduce the risk of bone loss, several measures can be taken, such as taking supplemental calcium throughout adulthood. Vitamin D is also necessary for the absorption of calcium; it is produced in the kidneys but sources include natural sunlight, fish and egg yolks. What you may not know is that exercise also increases bone mass by causing the bones to strengthen. You can accomplish this with weight-bearing activities such as walking and strength and resistance training.
If you consume too much calcium, it is possible to develop a condition called hypercalcemia can. Still, this is rare and usually associated with overactive parathyroid glands. The upper limit of calcium recommended for all ages older than 12 months is about 2,500 mg/day.
Prevention is better than cure
In summary, preventative measures include eating a healthy diet with adequate calcium and vitamin D consumption, regular physical activity, abstaining from smoking and excessive alcohol intake, and getting regular check-ups. Applying this baseline prescription for living healthily can help prevent osteoporosis as well as other chronic diseases. For your individual risk and prevention measures, see your doctor.
- National Institutes of Health, Department of Health and Human Services, National Institute of Arthritis and Musculoskeletal and Skin Diseases, “Osteopororsis;” May 2009
- National Institutes of Health, Office of Dietary Supplements, “Dietary supplement fact sheet: calcium;”
- Human Biology, Tenth Edition; Sylvia S. Mader; 2008;