Author
 |
DAWSON-HUGHES, BESS - Jean Mayer Human Nutrition Research Center On Aging At Tufts University |
|
Submitted to: American Society for Bone and Mineral Research
Publication Type: Book / Chapter Publication Acceptance Date: 5/1/2012 Publication Date: 8/1/2013 Citation: Dawson-Hughes, B. 2013. Calcium and Vitamin D. IN: Rosen, C.J., Bouillon, R., Compston, J.E., Rosen, V. Primer on the Metabolic Bone Diseases and Disorders of Mineral Metabolism. 8th Edition. American Society for Bone and Mineral Research. Wiley. p. 403-407. Interpretive Summary: Technical Abstract: Calcium is required for the bone formation phase of bone remodeling. Typically about 5 nmol (200 mg) of calcium is removed from the adult skeleton and replaced each day. To supply this amount, one would need to consume about 600 mg of calcium, since calcium is not very efficiently absorbed. Calcium also affects bone mass through its impact on the remodeling rate. An inadequate intake of calcium results in reduced calcium absorption, a lower circulating ionized calcium concentration, and an increased secretion of parathyroid hormone (PTH), a potent bone-resorbing agent. A high remodeling rate leads to bone loss; it is also an independent risk factor for fracture. Dietary calcium at sufficiently high levels, usually 1,000 mg per day or more, lowers the bone remodeling rate by about 10 to 20% in older men and women and the degree of suppression appears to be dose related(1). The reduction in remodeling rate accounts for the increase in BMD that occurs in the first 12 to 18 months of treatment with calcium. Adequate intakes of calcium and vitamin D are essential preventative measures and essential components of any therapeutic regimen for osteoporosis. Many men and women will need supplements to meet the intake requirements. There is no known advantage but there is potential risk in exceeding current calcium intake recommendations, particularly with use of supplements. Currently, the most common target serum 25OHD levels for musculoskeletal health are 50 nmol/l (20 ng/ml), recommended by the IOM, and 75 nmol/l (30 ng/ml), recommended by many specialty groups and others. There is a consensus that both of these target levels are safe. Additional research is needed to fully define the musculoskeletal and other health effects of different doses of vitamin D and serum 25OHD levels. |
