12～17岁少年钙代谢实验研究

目的通过钙代谢平衡实验探讨中国青春期少年的钙参考摄入量。方法从320名参与1年补钙实验4组12～17岁的少年中,每组随机抽取男、女生各10人,共80人。采用钙代谢平衡实验的方法。实验期共10d,膳食适应3d后,开始7d的代谢试验。收集研究对象试验期内摄入的食品、排出的粪便和尿液样品,用电感耦合等离子体发射光谱法测定样品中的钙含量。结果不同水平钙摄入组间的钙吸收量、粪钙排出量、钙储留量存在差异。钙表观吸收率女生平均为46.4%,男生68.7%。进行曲线拟合后,男生钙吸收率最高时的钙摄入量为665mg/d,女生钙吸收率达到平台时的钙摄入量为650mg。为了达到每日最大储留量,男生钙摄入量要达到545mg/d,女生要达到1055mg/d。结论中国12～17岁男生和女生的钙适宜摄入量有很大差别,男生钙适宜摄入量约为600～700mg/d,女生为1000～1100mg/d。     

青春前期女童钙代谢实验研究

目的:研究我国青春前期女童钙代谢状况,初步探讨该时期女童钙需要量。方法:选择49名处于生长突增期、未月经初潮的青春前期女童,采用经典钙代谢实验方法,在600～1500mg/d范围内设计4个不同的钙摄入剂量组,观察研究对象的钙代谢状况。结果:在600～1500mg/d钙摄入量范围内,各组对象钙表观钙吸收率未发现差别,平均吸收率为(53±0.12)%(范围52%～55%)。采用非线性回归模型对钙摄入量和钙储留量的关系进行拟合,钙摄入量在500mg/d时,钙储留量处于较低水平,钙摄入量在500～1000mg/d时,储留量快速增加,当钙摄入量达到1100mg/d时,钙储留量稳定在500mg/d左右的平台水平。结论:我国青春前期女童钙的表观吸收率为(53±0.12)%;青春前期女童达到最大钙储留量的最低钙摄入量是1100mg/d。     

彝族成年男子膳食中铁、锌、钙的生物利用研究

目的:评价彝族成年男子膳食中铁、锌和钙的生物利用情况,为防治该人群矿物质缺乏病提供基础信息。方法:以代谢平衡法于现场对12名20~22岁彝族世居地的成年男子进行14d试验。试验开始,收集对象空腹血,检测血红蛋白、红细胞压积、血清铁蛋白、血浆锌和钙浓度。试验期间,收集4~12d试验膳及摄入试验膳后排出的粪便和尿样。应用火焰原子吸收法测定膳食、粪便和尿中三种矿物质的含量,分别计算出它们的表观吸收率、平衡状态和表观利用率。结果:彝族成年男子代表性膳食中铁、锌和钙的表观吸收率(%)分别为15.8±6.2、24.5±4.1、32.3±9.7;表观利用率(%)分别为1.9±5.7、12.8±4.3、5.5±15.9。平衡试验显示铁,锌,钙均为平衡,但钙的变动范围较大。结论:膳食中铁、锌摄入量能满足试验对象的需要量,而钙的摄入量则不能满足其需要量。三种矿物质的表观吸收率与表观利用率基本上与我国正常人相同。建议彝族居民增加钙含量高的食物摄入量,以预防钙缺乏。     

藏族成年男子膳食中锌的吸收状况研究

目的了解藏族成年男子膳食中锌的吸收利用,为修订膳食营养素参考摄入量(DRIs)和改善锌的营养状况提供理论依据。方法在营养调查的基础上设计出代表性的3d食谱,选择13名18~19岁的藏族健康男子给予试验膳进行14d的代谢平衡实验,收集试验期受试者的膳食、饮水、粪便、尿液样品,采用火焰原子吸收光谱法测定各样品中锌的含量,计算锌的表观吸收率、表观利用率。结果锌的表观吸收率为24·15%,与现行的DRIs的制订依据估计值接近;表观利用率为7·61%。结论代表性膳食中锌的摄入量能满足受试者的需要量。     

山东省农村育龄妇女代表性膳食下铁、锌、钙吸收率分析

目的:研究山东省农村育龄妇女代表性膳食下铁、锌、钙的吸收率,以及膳食因素对它们吸收利用的影响。方法:用代谢平衡法,使用原子吸收分光光度计(AAS)测定膳食与粪便的铁、锌、钙,计算铁、锌、钙的吸收率。同时测定影响铁、锌、钙吸收的因子:膳食脂肪、蛋白、植酸、纤维素和VitC的含量,计算日平均摄入量,将其结果与我国育龄妇女每日推荐膳食营养素摄入量(RNI)进行比较。结果:铁、锌、钙的吸收率分别为8·26%、21·48%、47·94%,铁的平均日摄入量为13·77mg,占RNI的68·85%,远低于推荐量,锌的平均日摄入量为15·43mg,占RNI的102·87%,高于推荐量,钙的平均日摄入量为409·38mg,占RNI的51·17%,远低于推荐量。蛋白质和VitC的日摄入量分别为65·70g与34·20mg,占RNI的82·12%~109·50%和34·20%,低于推荐量。脂肪、植酸和膳食纤维的摄入量较高。结论:在蛋白质和抗坏血酸的日摄入量较低,脂肪、植酸和膳食纤维的摄入量较高的条件下,铁吸收率较低,铁营养缺乏,锌营养尚可,钙摄入量显著低于RNI,显示钙摄入严重不足。     

北京市郊区青春期少年植酸摄入量及其与钙铁锌的摩尔比值研究

目的通过调查农村青春期少年植酸的摄入量及其与钙、铁、锌的摩尔比值,评价其植酸摄入水平,为改善青少年对矿物质的吸收利用提供依据。方法随机选取北京市怀柔区某学校11～16岁中学生304人(男154人、女150人),采用连续3d24h回顾法进行膳食调查,并根据不同食物含量计算植酸及钙、铁、锌的摄入量。结果农村青春期少年植酸摄入量为620.5mg/d(男生670.0mg/d,女生569.6mg/d),性别差异有统计学意义(P<0.05)。植酸与钙、铁、锌的摩尔比值分别为0.1、2.1、4.4,植酸×钙/锌为34.9,性别差异无统计学意义。结论农村青春期少年植酸摄入量低于2002年全国平均水平和其他发展中国家水平,但高于西方发达国家水平,其摄入量可能会影响机体对钙、铁、锌的吸收。     

新疆某高校医学生膳食钙摄入状况

了解大学生膳食钙的摄入水平,为合理指导学生膳食营养提供参考.方法 采用整群随机抽样的方法,抽取新疆某高校医学生530名,通过自行设计的半定量食物频率问卷对研究对象食物摄入量进行调查,并评价钙摄入水平.结果 男生谷薯类、蔬菜、禽畜类、蛋类摄入量高于女生,女生水果类摄入量高于男生,差异均有统计学意义(P值均<0.01).学生钙平均摄入量为601 mg/d,占DRIs的75.1%,未达到膳食营养素参考摄入量标准,其中男生为605 mg/d,女生为598 mg/d,差异无统计学意义(t=0.440,P>0.05);学生膳食钙主要来自植物性食物(67.82%),奶及其制品来源的钙占25.61%.结论 学生膳食钙摄入不足,建议增加富含钙的食物摄入量.     

藏族成年男子膳食中铁的吸收状况研究

目的：了解藏族成年男子膳食中铁的吸收利用，为修订膳食营养素参考摄入量(DRIs)和改善铁的营养状况提供理论依据。方法：选择15名藏族成年健康男子给予代表性试验膳进行14d代谢平衡实验，收集血液样品测定铁营养状况指标，采用火焰原子吸收光谱法测定受试者的膳食、饮水、粪便、尿液样品中铁的含量。结果：受试者的铁营养状况正常、稳定。铁摄入量为61．96mg／d，粪铁排出量为42．16mg／d，尿铁排出量为6．95mg／d；铁表观吸收率为32．02％；铁表观利用率为20．79％，高于现行的DRIs的制订依据。结论：代表性膳食中铁的摄入量可满足受试者的需要量。     

山东省农村儿童代表性膳食中铁、钙吸收率分析

目的研究山东省农村学龄前儿童代表性膳食中铁、钙的吸收率,以及膳食因素对其吸收利用的影响.方法用代谢平衡法.使用原子吸收分光光度计（AAS）测定膳食与粪便的铁、钙含量,计算铁、钙的吸收率.同时测定影响铁、钙吸收的因子膳食脂肪、蛋白、植酸、纤维素和维生素C（VC）的含量,计算日平均摄入量,将其结果与我国儿童每日推荐膳食营养素摄入量（RNI）进行比较.结果铁、钙的吸收率分别为6.10%,53.09%,铁的平均日摄入量为11.80mg,占RNI的98.3%,低于推荐量;钙的平均日摄入量为295.40mg,占RNI的36.92%,低于推荐量.蛋白质和VC的日摄入量分别为31.2g与13.3mg,占RNI的56.73%和29.60%,低于推荐量.脂肪、植酸和膳食纤维的摄入量较高.结论在蛋白质和抗坏血酸的日摄入量较低,脂肪、植酸和膳食纤维的摄入量较高的条件下,铁吸收率较低,铁营养缺乏.钙摄入量显著低于RNI,显示钙摄入严重不足.     

49名9～11.5岁青春前期女童钙吸收率研究

目的研究中国青春前期女童钙代谢状况,了解中国青春前期女童钙吸收率和影响钙吸收率的因素。方法选择49名处于生长突增期、未月经初潮的青春前期女童,采用经典钙代谢实验方法,在600～1500mgd范围内设计4个不同的钙摄入剂量组,观察研究对象的钙代谢状况。结果在600～1500mgd钙摄入量范围内,各组对象钙表观钙吸收率未发现差别,平均吸收率为(53±0.12)%(范围52%～55%)。膳食蛋白质水平与钙吸收率、粪钙量无相关关系,尿钙与膳食磷含量、蛋白质含量显著负相关(P<0.01)。结论中国青春前期女童钙的表观吸收率为53%;高膳食蛋白质能增加尿钙的排出。     

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     

Calcium intake and bone mass development among Israeli adolescent girls.

OBJECTIVE: To determine the possible relationship between food and life style habits and bone health in adolescent Israeli females. METHODS: 2,000 adolescent Israeli Jewish and Arab high-school girls (mean age 14.5) completed a semi-quantitative food frequency questionnaire and a personal history questionnaire. 27 food components were calculated for each subject. Bone mineral content and density were determined for 112 subjects with calcium intake below 800 mg/day. RESULTS: Average calcium intake was found to be 1,260 mg/day, but 20% of all girls had a calcium intake below 800 mg/day. All low-energy diets were very low in calcium, as mean calcium intake per 1,000 calories was 411 128 grams. A large percentage of diets with less than 800 mg calcium were also deficient in phosphorus (95.2%), magnesium (84.8%). iron (90.5%) and zinc (100%). Due to differences in food sources. Jewish girls had more phosphorus in their diet, but less magnesium and iron compared to Arab girls. Calcium and zinc deficiencies in Jewish and Arab diets were similar. A negative correlation was found between body mass index (BMI) and age at menarche for all girls in the study. Bone mineral density (BMD) measured for girls with calcium intake below 800 mg/day distributed normally around the average when compared to age matched controls despite their low calcium intake. There was a strong positive correlation between BMD and bone mineral content (BMC) at all sites and body weights. CONCLUSIONS: Low calcium intake, other nutritional deficiencies and delayed menarche due to low-energy diet in the growing period and in adolescence may prevent the formation of healthy bones. There is no evidence of lower bone mass among the low calcium intake group in the study population at this stage. It remains to be documented if the window of opportunity for optimal bone accretion for this group will be missed in the future. possibly leading to increased risk of osteoporosis.     

Iron status in Swedish teenage girls: impact of low dietary iron bioavailability

OBJECTIVE: Although it is well known that bioavailability of iron in the diet is important, it has not been fully elucidated in practice. We investigated iron intake and iron absorption in the ordinary diet of free-living individuals in relation to iron status and assessed iron requirements. METHODS: From a total of 1245 adolescent boys and girls included in the G?teborg Adolescence Study of food habits, 28 adolescent girls registered their food intake during 7 d. Iron intake was assessed on the basis of these 7-d dietary records. Iron absorption was calculated using an algorithm including enhancing and inhibiting dietary factors on iron absorption in relation to individual iron status. RESULTS: Available iron intake was 11.5 +/- 2.8 mg/d (mean +/- SD). The proportion of girls with an iron intake below the Nordic nutrition recommendations was 85% (n = 24). Calculated iron absorption was 1.09 +/- 0.59 mg/d (mean +/- SD). Only four girls satisfied their estimated individual iron requirement concerning the absorbed amount of iron. Iron depletion (serum ferritin concentration < or = 15 microg/L) was present in 10 girls (36%), 2 of whom were also anemic (hemoglobin concentration < or = 120 g/L). CONCLUSION: Swedish adolescent girls seemed to have difficulties satisfying their iron requirement in terms of absorbed amount. The data support the view that iron intake and bioavailability of dietary iron is important when evaluating whether iron requirements have been met.     

Effect of zinc supplements on the intestinal absorption of calcium.

Pharmacologic doses of zinc are widely used as zinc supplements. As calcium and zinc may compete for common absorption sites, a study was carried out on the effect of a pharmacologic dose of zinc on the intestinal absorption of calcium in adult males. The analyzed dietary zinc intake in the control studies was normal, averaging 14.6 mg/day. During the high zinc study, 140 mg zinc as the sulfate was added daily for time periods ranging from 17 to 71 days. The studies were carried out during both a low calcium intake averaging 230 mg/day and during a normal calcium intake of 800 mg/day. Calcium absorption studies were carried out during the normal and high zinc intake by using an oral tracer dose of Ca47 and determining plasma levels and urinary and fecal excretions of Ca47. The study has shown that, during zinc supplementation, the intestinal absorption of calcium was significantly lower during a low calcium intake than in the control study, 39.3% vs 61% respectively, p less than 0.001. However, during a normal calcium intake of 800 mg/day, the high zinc intake had no significant effect on the intestinal absorption of calcium. These studies have shown that the high zinc intake decreased the intestinal absorption of calcium during a low calcium intake but not during a normal calcium intake.     

Effect of zinc supplements on the intestinal absorption of calcium

Pharmacologic doses of zinc are widely used as zinc supplements. As calcium and zinc may compete for common absorption sites, a study was carried out on the effect of a pharmacologic dose of zinc on the intestinal absorption of calcium in adult males. The analyzed dietary zinc intake in the control studies was normal, averaging 14.6 mg/day. During the high zinc study, 140 mg zinc as the sulfate was added daily for time periods ranging from 17 to 71 days. The studies were carried out during both a low calcium intake averaging 230 mg/day and during a normal calcium intake of 800 mg/day. Calcium absorption studies were carried out during the normal and high zinc intake by using an oral tracer dose of Ca47 and determining plasma levels and urinary and fecal excretions of Ca47. The study has shown that, during zinc supplementation, the intestinal absorption of calcium was significantly lower during a low calcium intake than in the control study, 39.3% vs 61% respectively, p less than 0.001. However, during a normal calcium intake of 800 mg/day, the high zinc intake had no significant effect on the intestinal absorption of calcium. These studies have shown that the high zinc intake decreased the intestinal absorption of calcium during a low calcium intake but not during a normal calcium intake.     

Calcium retention in adolescent boys on a range of controlled calcium intakes

BACKGROUND: National calcium requirements in the United States for boys are based on data from girls. On average, boys develop larger skeletons than do girls, yet it is unknown whether the additional skeletal accretion in boys requires additional dietary calcium intake. OBJECTIVE: The objective was to determine calcium retention in adolescent boys in response to a range of controlled intakes and to compare the intake needed for maximal retention in boys with that needed in adolescent girls studied under the same conditions. DESIGN: Thirty-one boys aged 12-15 y participated in 3-wk metabolic balance studies testing a range (700-2100 mg/d) of calcium intakes in a crossover study design with a 2-wk washout period. Calcium intake was varied by using a beverage fortified with calcium citrate malate. After a 1-wk equilibration period, calcium retention was calculated as dietary calcium intake minus the calcium excreted in the feces and urine over the following 2 wk. The dietary intake at which maximal calcium retention occurred was determined by using a nonlinear regression model. The results in boys were compared with those obtained in 35 adolescent girls previously studied under the same protocol. RESULTS: Maximal calcium retention in boys was achieved at an intake of 1140 mg/d. Calcium retention was higher (by 171 +/- 38 mg/d) in boys than in girls at all calcium intakes studied. CONCLUSION: The higher calcium retention in boys than in girls was attained through higher net calcium absorption and lower urinary excretion than in girls.     

西安市4 210例少儿血中微量元素及重金属元素结果分析

目的 通过检测0～12岁少儿血中钙、铁、锌、镁、铜、铅和镉水平,为预防疾病,科学合理的膳食提供理论依据。方法 收集灞桥区0～12岁少儿手指血样4 210例,进行微量元素和重金属元素的检测,分为4个年龄组,分别为0～1岁,1～3岁,3～7岁,7～12岁,进行资料收集和统计分析。结果 不同年龄段儿童的微量元素和重金属元素的平均值之间存在统计学差异（P＜0.05）;0～12岁儿童钙、铁和锌元素的总体缺乏率分别为24.94%,19.19%和13.85%,差异有统计学意义（P＜0.05）;镁和铜元素的缺乏率在不同年龄段中无统计学差异;未见铅镉水平超标;男童和女童在钙、铁、锌元素的缺乏率上存在差异,镁和铜元素在男女童之间无明显差异。结论 灞桥区儿童钙、铁缺乏较为明显,锌其次,铜和镁元素基本不缺乏。应提高家长和民众对微量元素和重金属元素的认识,同时发现微量元素的缺乏,应该尽早纠正,科学补充微量元素。