Calcium supplements  increased BMD by 0.7 - 1.8 % at all five skeletal sites at one , two , and over two and a half years , but the size of the increase in BMD at later time points was similar to the increase at one year .
Increasing calcium intake from dietary sources or by taking calcium supplements produces small non-progressive increases in BMD , which are unlikely to lead to a clinical ly significant reduction in risk of fracture
OBJECTIVE To determine whether increasing calcium intake from dietary sources affects  bone mineral density ( BMD ) and , if so , whether the effects are similar to those of calcium supplements .
Acute and 3-month effects of microcrystalline hydroxyapatite, calcium citrate and calcium carbonate on serum calcium and markers of bone turnover: a randomised controlled trial in postmenopausal women.
Ca supplements are used for bone health ; however , they have been associated with increased cardiovascular risk , which may relate to their acute effects on serum Ca concentrations . Microcrystalline hydroxyapatite ( MCH ) could affect serum Ca concentrations less than conventional Ca supplements , but its effects on bone turnover are unclear . In the present study , we compared the acute and 3-month effects of MCH with conventional Ca supplements on concentrations of serum Ca , phosphate , parathyroid hormone and bone turnover markers . We r and omised 100 women ( mean age 71 years ) to 1 g/d of Ca as citrate or carbonate ( citrate-carbonate ) , one of two MCH preparations , or a placebo . Blood was sample d for 8 h after the first dose , and after 3 months of daily supplementation . To determine whether the acute effects changed over time , eight participants assigned to the citrate dose repeated 8 h of blood sampling at 3 months . There were no differences between the citrate and carbonate groups , or between the two MCH groups , so their results were pooled . The citrate-carbonate dose increased ionised and total Ca concentrations for up to 8 h , and this was not diminished after 3 months . MCH increased ionised Ca concentrations less than the citrate-carbonate dose ; however , it raised the concentrations of phosphate and the Ca-phosphate product . The citrate-carbonate and MCH doses produced comparable decreases in bone resorption ( measured as serum C-telopeptide ( CTX ) ) over 8 h and bone turnover ( CTX and procollagen type-I N-terminal propeptide ) at 3 months . These findings suggest that Ca preparations , in general , produce repeated sustained increases in serum Ca concentrations after ingestion of each dose and that Ca supplements with smaller effects on serum Ca concentrations may have equivalent efficacy in suppressing bone turnover
Calcium supplements  increased BMD by 0.7 - 1.8 % at all five skeletal sites at one , two , and over two and a half years , but the size of the increase in BMD at later time points was similar to the increase at one year .
Increasing calcium intake from dietary sources or by taking calcium supplements produces small non-progressive increases in BMD , which are unlikely to lead to a clinical ly significant reduction in risk of fracture
OBJECTIVE To determine whether increasing calcium intake from dietary sources affects  bone mineral density ( BMD ) and , if so , whether the effects are similar to those of calcium supplements .