The Effect of Vitamin D on Calcium Absorption in Older Women
The Effect of Vitamin D on Calcium Absorption in Older Women
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DOI：
10.1210/jc.2012-2020
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发表时间：
2012-10-01
影响因子：
5.8
通讯作者：
Smith, Lynette M.
中科院分区：
文献类型：
--
作者：
Gallagher, J. Christopher;Yalamanchili, Vinod;Smith, Lynette M.
背景：维生素D通常被推荐与钙补充剂一起使用，以增加吸收。目前还没有关于维生素D对钙吸收的系统性研究表明应该推荐什么剂量。目的：我们的目的是研究增加维生素D-3剂量对钙吸收的影响。设计和设置：我们在内布拉斯加州奥马哈市的克雷顿大学医学中心进行了一项随机双盲安慰剂对照试验。参与者：参与者包括163名绝经后维生素D不足的白人妇女，定义为血清25-羟基维生素D（25 OHD）低于20 ng/ml干预：参与者随机接受维生素D-3剂量之一，400，800，1600，2400，3200，4000或4800 IU/d，或安慰剂1年。钙的摄入量增加到1200-1400毫克，每天给予每日柠檬酸钙。主要成果：我们评估了钙吸收的变化对维生素D。结果：平均血清25 OHD增加从基线15.6 ng/ml（39 nmol/L）至46.5 ng/ml（112 nmol/L）的受试者随机最高剂量的维生素D（4800 IU）。钙吸收与血清25 OHD的相关性（R-2 = 0.50; P = 0.001）比剂量（R-2 = 0.47; P = 0.033）更显著。在血清25 OHD范围为20-66 ng/ml（50-165 nmol/L）时，100 mg剂量的钙吸收从52-58%（6 mg）增加。结论：没有证据表明在血清25 OHD范围为10-66 ng/ml（25-165 nmol/L）时钙吸收减少的阈值。高剂量维生素D吸收的钙增加6%是如此之小，可以从半杯牛奶（100毫升）或100毫克元素钙中获得相同的量。结果挑战了关于添加维生素D以增加钙吸收的价值的假设，除非血清25 OHD非常低，低于10 ng/ml（25 nmol/L）。（临床内分泌代谢杂志97：3550-3556，2012）
Context: Vitamin D is often recommended for use with calcium supplements to increase absorption. There are no systematic studies of vitamin D on calcium absorption that indicate what dose should be recommended.Objective: Our objective was to study the effect of increasing doses of vitamin D-3 on calcium absorption.Design and Setting: We conducted a randomized double-blind placebo-controlled trial at Creighton University Medical Center, Omaha, NE.Participants: Participants included 163 postmenopausal Caucasian women with vitamin D insufficiency, defined as a serum 25-hydroxyvitamin D (25OHD) below 20 ng/ml (50 nmol/liter).Intervention: Participants were randomized to receive one of the vitamin D-3 doses, 400, 800, 1600, 2400, 3200, 4000, or 4800 IU/d, or placebo for 1 yr. Calcium intake was increased to 1200-1400 mg daily by giving daily calcium citrate.Main Outcome: We evaluated the change in calcium absorption on vitamin D.Results: Mean serum 25OHD increased from baseline 15.6 ng/ml (39 nmol/liter) to 46.5 ng/ml (112 nmol/liter) in subjects randomized to the highest dose of vitamin D (4800 IU). Calcium absorption was more significantly related to serum 25OHD (R-2 = 0.50; P = 0.001) than dose (R-2 = 0.47; P = 0.033). Calcium absorption of a 100-mg dose increased from 52-58% (6 mg) over a serum 25OHD range of 20-66 ng/ml (50-165 nmol/liter).Conclusions: There was no evidence of a threshold for reduced calcium absorption in the serum 25OHD range of 10-66 ng/ml (25-165 nmol/liter). The increase in absorbed calcium of 6% on high doses of vitamin D is so small that the same amount could be obtained from half a glass of milk (100 ml) or 100 mg elemental calcium. The results challenge assumptions about the value of adding vitamin D to increase calcium absorption except when serum 25OHD is very low that is less than 10 ng/ml (25 nmol/liter). (J Clin Endocrinol Metab 97: 3550-3556, 2012)