Wood R J, Zheng J J
Mineral Bioavailability Laboratory, Jean Mayer US Department of Agriculture, HNRCA, Tufts University, Boston, MA 02111, USA.
Am J Clin Nutr. 1997 Jun;65(6):1803-9. doi: 10.1093/ajcn/65.6.1803.
Optimal calcium intakes of 37.5 mmol(1500 mg)/d have been proposed for elderly people. We investigated the effects of calcium supplementation on zinc absorption and balance in 18 relatively healthy, postmenopausal women aged 59-86 y. All subjects received a standardized basal diet of typical foods supplying 269 mumol (17.6 mg) Zn/d and 22.2 mmol (890 mg) Ca/d during the 36-d study. In two of three experimental periods, an additional 11.7 mmol (468 mg) Ca/d as either milk or an inorganic calcium phosphate supplement was provided. Net zinc absorption and zinc balance were significantly reduced by approximately 2 mg/d during both high-calcium treatments. In a second study, conducted in a separate group of men and women aged 21-69 y, a whole-gut lavage, zinc-absorption test was used to investigate the acute effect of a 15-mmol CaCO3 (600 mg Ca) supplement, with and without extra zinc, on zinc absorption from a single test meal supplying 111.7 mumol (7.3 mg) Zn. Zinc absorption was reduced significantly by 50% when the calcium supplement was given with the meal. Inclusion of an extra 119.3 mumol (7.8 mg) Zn as part of a calcium supplement offset the detrimental effect of calcium on zinc absorption. Our findings suggest that high-calcium diets can reduce net zinc absorption and balance and may increase the zinc requirement in adult humans.
有人提出老年人的最佳钙摄入量为37.5毫摩尔（1500毫克）/天。我们调查了补钙对18名年龄在59 - 86岁、相对健康的绝经后女性锌吸收和平衡的影响。在为期36天的研究中，所有受试者都接受了一份标准化的基础饮食，该饮食由典型食物组成，每天提供269微摩尔（17.6毫克）锌和22.2毫摩尔（890毫克）钙。在三个实验阶段中的两个阶段，额外补充了11.7毫摩尔（468毫克）钙/天，补充形式为牛奶或无机磷酸钙补充剂。在两种高钙处理期间，净锌吸收和锌平衡均显著降低了约2毫克/天。在第二项研究中，对另一组年龄在21 - 69岁的男性和女性进行了全肠道灌洗锌吸收试验，以研究15毫摩尔碳酸钙（600毫克钙）补充剂在有或没有额外锌的情况下，对从提供111.7微摩尔（7.3毫克）锌的单一测试餐中吸收锌的急性影响。当补钙剂与餐食一起服用时，锌吸收显著降低了50%。在补钙剂中额外添加119.3微摩尔（7.8毫克）锌可抵消钙对锌吸收的不利影响。我们的研究结果表明，高钙饮食会降低净锌吸收和平衡，并可能增加成年人对锌的需求量。
