title: 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.
authors.affiliation: Department of Foods and Nutrition, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shahnazari
authors.forename: Berdine R
authors.initials: BR
authors.lastname: Martin
authors.forename: Leecole L
authors.initials: LL
authors.lastname: Legette
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Lachcik
authors.forename: Jo
authors.initials: J
authors.lastname: Welch
authors.forename: Connie M
authors.initials: CM
authors.lastname: Weaver
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects*; D015519:Bone Density / Q000187:drug effects / Q000502:physiology*; D001842:Bone and Bones / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D002119:Calcium Carbonate / Q000737:chemistry / Q000494:pharmacology*; D002136:Calcium, Dietary / Q000494:pharmacology*; D019587:Dietary Supplements; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D015663:Osteoporosis, Postmenopausal / Q000517:prevention & control; D010052:Ovariectomy; D010316:Particle Size; D051381:Rats; D015430:Weight Gain / Q000187:drug effects
chemical_list: D002136:Calcium, Dietary; D002119:Calcium Carbonate; D002118:Calcium