Habitual dietary calcium intakes and calcium metabolism in healthy adults Chinese: a systematic review and meta-analysis.

To investigate the metabolic differences of calcium requirements between Chinese and Westerners, we examined systematically the characteristics of calcium metabolism in Chinese adults with habitual dietary calcium intakes. We searched PubMed, Cochrane Library, SinoMed, and National Index to Chinese Newspapers & Periodicals, from inception to March 17, 2015, as well as the bibliographies of any relevant papers and journals, for trials assessing calcium metabolism in healthy Chinese adults within 18-60 years of age on the typical Chinese diet. We extracted a standardized dataset from metabolic studies that reported intake, retention, urinary excretion, faecal excretion and/or fractional absorption of calcium. We pooled data with a random effects meta-analysis. Of 2,046 citations identified by the search strategy, 12 studies (comprising 137 participants, 13 aggregate data deriving from 257 individual data) met the inclusion criteria. Metabolic data with self-chosen or typical Chinese diets were analyzed. Mean daily intakes of calcium ranged between 288 and 948 mg. Mean calcium retentions of each study were between 13 and 294 mg/d. The overall pooled value for dietary intake, urinary excretion, faecal excretion, retention and fractional absorption of calcium were 583 mg/d, 117 mg/d, 381 mg/d, 72 mg/d and 33.3%. Dietary calcium intake and faecal calcium excretion explained almost 85% of the heterogeneity of calcium retention. Chinese adults could maintain a positive calcium balance with plant-based diets at calcium intakes as low as 300 mg/d through increasing fractional calcium absorption and decreasing calcium excretion in urine and faeces.为了探讨中国人与西方人之间钙需要量的代谢差异，我们系统地研究了中国 成人在习惯性膳食钙摄入水平下的钙代谢特点。从PubMed、Cochrane Library 、中国生物医学文献数据库（SinoMed 中心网络版）、全国报刊索引数 据库—篇名库及相关论文和期刊的参考文献，检索2015 年3 月17 日之前发 表的18-60 岁中国健康成人在典型中国膳食条件下的钙代谢试验。采用结构 式数据库提取报道了钙摄入量、钙储留量、尿钙排出量、粪钙排出量和/或表 观钙吸收率的代谢试验信息。采用随机效应荟萃分析模型汇总数据。在检索 到的2,046 篇文献中，有12 个研究符合纳入标准，包括由137 名受试者的 257 条个体数据汇总得到的13 条聚合数据。分析以自选膳食或者典型中国膳 食为试验餐的代谢数据。各研究平均膳食钙摄入量介于288-948 mg/d 之间， 平均钙储留量介于13-294 mg/d 之间。汇总的膳食钙摄入量、尿钙排出量、 粪钙排出量、钙储留量和表观钙吸收率分别为583 mg/d、117 mg/d、381 mg/d、72 mg/d 和33.3%。膳食钙摄入量和粪钙排出量共解释了约85%的钙储 留量异质性。以植物性膳食为主的中国成人在钙摄入量低至300 mg/d 时仍能 通过增加表观钙吸收率和减少尿粪钙排出量来维持正钙平衡。.