Heller Howard J, Poindexter John R, Adams-Huet Beverley
Center for Mineral Metabolism and Clinical Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75390-8885, USA.
J Clin Pharmacol. 2002 Nov;42(11):1251-6. doi: 10.1177/009127002762491343.
The authors hypothesized that estrogen treatment or vitamin D status may affect the bioavailability of two common calcium supplements differently. Using data derived from a recent trial in 25 postmenopausal women, the authors found that deltaAUC of serum calcium after subtraction of placebo was significantly higher after calcium citrate (median, 0.85; 25th to 75th percentile, 0.70 to 3.15) than after calcium carbonate (0.25; -0.58 to 1.00) in non-estrogen-treated patients. There was no difference in the bioavailability of calcium between the two calcium formulations in estrogen-treated patients. Bioavailability was also significantly higher with the citrate salt for the subgroups with lower serum 25-hydroxyvitamin D and higher serum 1,25-dihydroxyvitamin D concentrations. In summary, bioavailability of calcium from the calcium carbonate product was more dependent on estrogen treatment and vitamin D status than that of calcium citrate. This may explain the variable results of reported calcium supplementation studies.
作者推测，雌激素治疗或维生素D状态可能对两种常见钙补充剂的生物利用度产生不同影响。利用最近一项针对25名绝经后女性的试验数据，作者发现，在未接受雌激素治疗的患者中，减去安慰剂后，柠檬酸钙组血清钙的AUC变化值（中位数为0.85；第25至75百分位数为0.70至3.15）显著高于碳酸钙组（0.25；-0.58至1.00）。在接受雌激素治疗的患者中，两种钙制剂的钙生物利用度没有差异。对于血清25-羟基维生素D水平较低和血清1,25-二羟基维生素D浓度较高的亚组，柠檬酸盐的生物利用度也显著更高。总之，碳酸钙产品中钙的生物利用度比柠檬酸钙更依赖于雌激素治疗和维生素D状态。这可能解释了所报道的补钙研究结果的差异。
