Andon M B, Ilich J Z, Tzagournis M A, Matkovic V
Procter & Gamble Company, Miami Valley Laboratories, Cincinnati, OH 45253-8700, USA.
Am J Clin Nutr. 1996 Jun;63(6):950-3. doi: 10.1093/ajcn/63.6.950.
Increasing emphasis is being placed on optimizing calcium intake during growth as a way to enhance peak bone mass. Although some studies in adults have shown that high calcium intake may negatively affect magnesium utilization, few data are available regarding the interaction of calcium and magnesium in healthy children. The purpose of our study was to measure the effect of calcium intake on magnesium balance in 26 adolescent girls (mean age 11.3 y) during a 14-d period. Subjects ate a controlled basal diet containing 667 mg Ca and 176 mg Mg. In addition to the basal diet, subjects were randomly assigned in a double-blind fashion to consume 1000 mg elemental Ca/d as calcium citrate malate or a placebo. Magnesium use did not differ between the low-calcium and high-calcium groups as measured by absorption (50% compared with 55%), urinary excretion (70 compared with 74 mg/d), and fecal excretion (88 compared with 79 mg/d). Accordingly, magnesium balance was not different in subjects consuming 667 or 1667 mg Ca/d and averaged 21 mg Mg/d for the whole study group. Magnesium balance was significantly correlated with magnesium intake (r = 0.511, P = 0.008) and magnesium absorption (r = 0.723, P < 0.001). Prediction intervals from the regression of magnesium balance on intake indicated that the current recommended dietary allowance of magnesium would result in magnesium balance > or = 8.5 mg/d in 95% of the girls. This value appears consistent with long-term accretion rates needed to account for the expansion of the total-body magnesium pool during growth. In summary, our observations support the adequacy of the current recommended dietary allowance for magnesium and indicate that alterations in magnesium utilization should not be anticipated in adolescent females consuming a high-calcium diet.
人们越来越重视在生长过程中优化钙的摄入量，以此来提高峰值骨量。虽然一些针对成年人的研究表明，高钙摄入量可能会对镁的利用产生负面影响，但关于健康儿童钙和镁相互作用的数据却很少。我们研究的目的是在14天的时间里，测量钙摄入量对26名青春期女孩（平均年龄11.3岁）镁平衡的影响。受试者食用一种控制好的基础饮食，其中含有667毫克钙和176毫克镁。除基础饮食外，受试者被随机双盲分配，每天摄入1000毫克元素钙（以苹果酸钙形式）或安慰剂。通过吸收（分别为50%和55%）、尿排泄（分别为70和74毫克/天）和粪排泄（分别为88和79毫克/天）来衡量，低钙组和高钙组之间的镁利用情况没有差异。因此，每天摄入667或1667毫克钙的受试者的镁平衡没有差异，整个研究组的平均镁平衡为每天21毫克。镁平衡与镁摄入量（r = 0.511，P = 0.008）和镁吸收（r = 0.723，P < 0.001）显著相关。根据镁平衡摄入量回归得出的预测区间表明，目前推荐的镁膳食摄入量会使95%的女孩的镁平衡≥8.5毫克/天。这个数值似乎与生长期间全身镁池扩张所需的长期累积率一致。总之，我们的观察结果支持目前推荐的镁膳食摄入量是足够的，并表明在食用高钙饮食的青春期女性中，不应预期会出现镁利用的改变。
