12～14岁男童体内强化去植酸豆粉中钙铁锌的吸收利用率研究

目的　为了解我国少年儿童对豆粉、去植酸豆粉和牛奶中钙、铁、锌的吸收利用率 ,通过普及饮用豆粉 ,改善我国居民蛋白质和矿物质的营养状况提供理论依据。方法　选择 57名 1 2～ 1 4岁男童 ,按年龄、身高、体重和血红蛋白含量匹配 ,分成 3组 ,分别给予强化豆粉、强化去植酸豆粉和强化牛奶 2 2 0ml,其中含钙 2 70mg、铁 4mg、锌 4mg。给予受试者用稳定性核素4 4Ca、58Fe和70 Zn标记的受试物 ,以亮蓝和镝标记粪便 ,收集粪便样品 ,测量强化去植酸豆粉、豆粉和强化牛奶中钙、铁、锌的吸收率 ;使用热离子化质谱法测定粪便中4 4Ca含量 ;应用感应耦合等离子质谱法测定粪便中58Fe和70 Zn的丰度及镝的含量 ,计算铁、锌的表观吸收率 ,并以镝的回收率进行校正。结果　豆粉组、牛奶组和去植酸豆粉组的铁吸收率分别为 (6 7± 3 8) %、(1 5 5± 9 2 ) %和 (2 0 6± 7 3) % ,钙吸收率分别为 (43 5±1 0 7) %、(64 2± 1 1 4) %和 (50 9± 6 6) % ,锌吸收率分别为 (1 1 3± 6 5) %、(31 2± 1 0 4) %和 (2 0 1±7 4) %。强化豆粉经去除植酸处理后 ,钙、铁、锌的吸收率显著高于未去植酸的豆粉 ;牛奶中钙和锌的吸收率高于去植酸强化豆粉 ;经去除植酸处理后的豆粉中铁吸收率高于牛奶 ,但差异无显著性。我国儿童由于

A study on absorption and utilization of calcium,iron and zinc in mineral-fortified and dephytinized soy milk powder consumed by boys aged 12 to 14 years

OBJECTIVES: In order to understand the absorption and utilization of calcium, iron and zinc in cow milk, soy milk powder and dephytinized soy milk powder in the children and adolescents, and to lay a foundation for the improvement of protein and mineral nutrition in Chinese residents with popularizing consumption of soy milk powder. METHODS: Totally, 57 boys aged 12 to 14 years were selected and divided into three groups, matched by age, hemoglobin concentration, height and weight. The boys were given 220 ml of fortified and dephytinized soy milk, soy milk or cow milk, respectively, containing calcium 270 mg, iron 4 mg and zinc 4 mg, which were labeled with stable isotopes (44)Ca, (58)Fe and (70)Zn in a single serving size, and their feces were labeled with brilliant blue and dysprosium. Feces specimens were collected for all the subjects and absorption rate of calcium, iron and zinc were measured for all the children who took fortified and dephytinized soy milk, soy milk or cow milk, respectively. Calcium in feces was measured with heat ionized mass spectrometry, and recovery of (58)Fe and (70)Zn in feces and content of dysprosium were measured with induction coupling iso-ionic mass spectrometry, and then absorption rates of iron and zinc were calculated and adjusted by the recovery rate of dysprosium. RESULTS: Iron absorption rate was (6.7 +/- 3.8)% in soy milk powder group, (15.5 +/- 9.2)% in the cow milk group and (20.6 +/- 7.3)% in dephytinized soy milk powder group, respectively. Calcium absorption rate was (43.5 +/- 10.7)%, (64.2 +/- 11.4)%, and (50.9 +/- 6.6)% in the three groups, respectively. Absorption rate of zinc was (11.3 +/- 6.5)%, (31.2 +/- 10.4)% and (20.1 +/- 7.4)%, respectively. Significant increase in absorption of calcium, iron and zinc was observed in the groups with fortified and dephytinized soy milk powder, as compared with those consuming nondephytinized soy milk powder. Absorption rate of calcium and zinc was significantly higher in the group with cow milk than that in the group with dephytinized and fortified soy milk powder, and iron bioavailability was lower in the group with cow milk than that with dephytinized soy milk powder, with no significant difference. Absorption rates of calcium, iron and zinc were higher in children of China due to their long term adaptation to dietary intake of lower mineral and protein, and higher fiber. CONCLUSIONS: Bioavailability of calcium, iron and zinc in soy milk powder could be increased by dephytinized treatment for it.