Diet Calcium Level but Not Calcium Supplement Particle Size Affects Bone Density and Mechanical Properties in Ovariectomized Rats ,

Abstract

Calcium (Ca) supplements, especially Ca carbonate (CaCO3), are the main alternative sources of dietary Ca and an important part of a treatment regimen for osteoporosis, the most common metabolic bone disorder of aging and menopause. In a female ovariectomized (OVX) rat model for studying postmenopausal osteoporosis, we tested the hypothesis that a small compared with a large particle size of CaCO3 (13.0- vs. 18.5-mum geometric diameter) would result in increased Ca balance and subsequently bone mass and that this would be affected by dietary Ca level. We used 6-mo-old rats that were OVX either at 6 or 3 mo of age as models of early or stable menopausal status, respectively. The rats received semipurified diets that contained either 0.4 or 0.2% dietary Ca provided from CaCO3 of 2 particle sizes. A group of Sham-operated rats with intact ovaries served as control and were fed 0.4% dietary Ca from large particles. Estrogen deficiency as a result of ovariectomy had an adverse effect on bone density, mineral content, and bone mechanical properties (P < 0.001). Reducing dietary Ca from 0.4 to 0.2% resulted in significant adverse effects on bone density and mechanical properties (P < 0.001). The particle size of CaCO3 did not affect total Ca balance, bone dual energy X-ray absorptiometry and peripheral quantitative computed tomography indices, bone ash and Ca content, or the mechanical determinants of bone strength. We conclude that a decrease in particle size of CaCO3 to 70% of that typically found in Ca supplements does not provide a benefit to overall Ca metabolism or bone characteristics and that the amount of Ca consumed is of greater influence in enhancing Ca nutrition and skeletal strength.

Solubility and bioavailability of stabilized amorphous calcium carbonate

“…Acclimation of the rats prior to the administration was performed using a 0.2% calcium diet instead of 1% calcium, which, according to several reports, is suggested to be the optimal diet for calcium bioavailability assays. (41,42) The analysis of calcium content in the feces and femurs was performed using a decalcification solution instead of ashing the radioactive substances in a muffle furnace, as reported previously, (33,42,43) owing to environmental restrictions. This method proved to be highly accurate ($95%) when compared with the ashing technique (data not shown).…”

The antidepressant bupropion exerts alleviating properties in an ovariectomized osteoporotic rat model

“…Samples were incubated overnight in a shaking water bath at 37 °C. The acidic ash mixture was diluted with deionized distilled water in a 1/9 ratio [42] . The diluted samples were used to measure calcium (Ca 2+ ), inorganic phosphorus (PO 4 2-) and magnesium (Mg 2+ ) concentrations.…”

Synergistic antiosteoporotic effect of <i>Lepidium Sativum</i> and alendronate in glucocorticoid-induced osteoporosis in wistar rats

“…The measurements obtained were expressed as the percentages of the ash amounts relative to the dry weight of the vertebra. The ash was then solubilized in 6 N HCl and analysed for Ca content as described previously (Shahnazari et al, 2009). Values were expressed as milligram of Ca per cubic centimetre of bone volume.…”