稳定性同位素示踪测定NaFeEDTA强化酱油中铁在人体中吸收率

采用铁稳定性同位素54Fe和58Fe分别标记FeSO4及NaFeEDTA并以稀土元素 (Dy)作为排泄物回收标记物。自愿受试人群为 18～ 2 2岁健康女性。采用我国典型城镇成年女性膳食模式。两种铁剂及Dy以酱油为食物载体一同分 2日 6次经口给入。实验其间每日留取受试人膳食样品并完全收集受试人在实验期的排泄物。采用原子吸收和ICP -MS分别检测膳食及排泄物中总铁含量和铁同位素比例 ,对两种铁剂中的铁的吸收率进行比较。结果表明 ,FeSO4中铁在人体中的平均吸收率为 4 73% ,NaFeEDTA为 10 5 1%。二者差异为极显著(P <0 0 1)。说明NaFeEDTA中铁的吸收率优于FeSO4。     

同位素示踪法测定儿童铁的吸收率

目的:研究农村代表性膳食条件下儿童铁的吸收率。方法:采用天然低丰度稳定性同位素Fe标记FeSO4,以稀土元素镝(Dy)作为排泄物回收标记物。自愿受试者为4～6岁身体健康的农57村儿童。采用山东农村代表性膳食模式。同位素标记铁与Dy以饼干为载体分两天三餐前经口给予。实验期间每日留取受试者膳食样品并收集受试者在实验期的粪便,采用原子吸收(AAS)和热电离质谱(TIMS)分别检测膳食和粪便中总铁含量与Fe/56Fe比值,计算铁的吸收率。同时对脂肪、瘦肉、57蛋白、植酸、纤维素和VC的日摄入量进行测定,并将结果与我国每日营养推荐膳食供给量(DRI)比较。结果:铁的吸收率(%)为6.06±2.24,远低于1988年我国修订推荐RDA所参考国外的10%,铁的平均日摄入量为10.29mg,占DRI的102.9%,其中血红素铁平均日摄入量占总铁日摄入量的17.49%,基本达到推荐量。蛋白质和抗坏血酸的日摄入量仅占DRI的56.73%和29.60%远低于推荐量。脂肪、植酸和膳食纤维的摄入量较高。结论:按目前山东农村的膳食模式,儿童铁日摄入量已达推荐量,但吸收率偏低,因而铁摄入量仍不足。蛋白质和抗坏血酸的日摄入量较低。     

稳定性同位素评价藏族青年男子膳食铁的吸收率

目的用铁的稳定性同位素示踪剂评价藏族青年男子膳食铁的吸收率,为改善该人群膳食铁吸收的提供参考数据。方法于现场进行人体代谢试验,受试者口服稳定性同位素示踪铁剂(浓集57Fe的FeSO4)及稀土元素镝,粪便监测法收集示踪剂排出粪样;用感耦等离子体质谱仪测定粪样57Fe56Fe的比值,分析评价该人群膳食铁的吸收率。结果口服同位素评价藏族青年男子膳食铁的吸收率为13.4%±6.4%;每日示踪剂铁和镝排出呈良好相关性。结论稀土元素镝与未吸收的示踪剂铁在消化道有一致的排出过程,前者的回收率能很好反映粪样收集情况;藏族成年男子膳食铁的吸收较好。     

稳定同位素示踪法测定青春前期儿童铁吸收率

目的利用稳定同位素示踪技术评价青春前期儿童铁吸收率。方法利用人工富集57Fe标记并制备为57FeSO4口服剂,在常规膳食模式下,早、晚餐前经口给予57名受试者,共5天。收集规定时间内受试者全部粪便,前处理后分别经原子吸收分光光度计(AAS)和多接受等离子质谱仪(MC-ICP-MS)测定铁的含量和丰度,以评价青春前期儿童铁的吸收率情况。结果男、女性儿童铁表观吸收率分别为(26.71±2.94)%和(29.76±2.20)%,校正回收率分别为(27.45±2.83)%和(31.01±2.48)%,男性均显著低于女性儿童(P0.05)。结论空腹口服稳定同位素示踪剂条件下,青春期儿童铁吸收率均较高,但男性吸收率略低于女性。     

山东农村典型膳食儿童人体锌吸收率研究

目的研究山东农村典型膳食锌(Zn)在农村儿童人体吸收率及Zn吸收相关营养素的日摄入量。方法受试者为4～6岁身体健康的农村儿童。标记稳定性同位素67Zn3.0mg,晚餐前一次经口给予,采用原子吸收法(AAS)和热电离质谱(TIMS)分别检测膳食和粪便中总锌含量与67Zn/68Zn比值,计算锌的吸收率,并对膳食铁、钙、脂肪、蛋白、植酸、纤维素和维生素C(VC)含量测定,将结果与我国儿童日推荐膳食营养素摄入量(RNIs)比较。结果锌的吸收率为(12.94±3.32)%,锌的平均日摄入量为11.16mg,占RNI的96.7%,蛋白质和抗坏血酸的日摄入量分别为31.2g与13.3mg,占RNI的62.4%和19.0%。结论在目前山东农村的膳食模式下,儿童体内锌的吸收率偏低,蛋白质和抗坏血酸的日摄入量不足。     

牛奶生物发酵对大鼠肠道铁吸收率的影响

目的:通过牛奶生物发酵对肠道铁吸收率影响的实验研究,为高生物利用率补铁食品开发提供实验依据;方法:Wistar雄性大鼠30只,随机分为实验组和对照组.大鼠以去铁基础饲料喂养3 d后,对照组经灌胃法给予含80μg 55Fe的Na55Fe EDTA强化牛奶;实验组经灌胃法给予含80μg 55Fe的Na55Fe EDTA生物发酵酸奶,用LS6500型液体闪烁计数仪检测粪便及血液、肝、脾等组织中55Fe含量;结果:实验组动物肠道55Fe的吸收率为(15.2±3.4)%;对照组为(11.0±3.2)%,两组差异非常显著(P＜0.01);血液55Fe含量实验组为(0.92±0.37)mg/L,对照组为(0.76±0.29)mg/L,差异也非常显著(P＜0.01);实验组肝和脾中55Fe含量虽高于对照组,但差异并不显著.结论:牛奶生物发酵能明显提高肠道铁的吸收率.     

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。     

应用ICP-MS的ORS技术进行人体铁稳定同位素代谢示踪研究的初探

目的应用四极杆型电感耦合等离子体质谱仪(ICP-MS)配合最新的八极杆碰撞/反应池(ORS)消干扰技术进行Fe的同位素比测定研究。方法于现场进行人体代谢试验,受试者口服57Fe稳定性同位素示踪剂,以卡红为标志,粪便监测法收集试验期内的所有粪样,测定粪样中57Fe/56Fe的比值。结果运用ICP-MS的ORS技术可消除由Ar等离子体本身以及样品中存在的Ca等产生的多原子离子对Fe带来的干扰;稀释实际样品到一定范围,基体干扰可忽略不计;标准样品和实际样品短期及长期精密度均小于0.3%;测定两组受试者粪样中的57Fe/56Fe的比值,发现代谢后排泄出的57Fe遵循一定的变化趋势,从而可以测定人体对Fe的代谢吸收比率。结论该技术可准确测定粪样中57Fe/56Fe的比值,可以用来计算评价膳食中铁吸收率的情况,追踪铁在人体中的代谢过程。     

湖南、湖北等省成年人膳食锌吸收率分析

目的 评价我国湖南、湖北等省成年人膳食结构中Zn的吸收率,为我国不同人群、不同膳食结构的Zn吸收率研究提供参考资料.方法 采用67ZnSO4锌稳定性同位素示踪法,以稀土元素镱(Yb)为粪便回收标记物,进行现场人体代谢实验.受试者为健康成年男子和育龄妇女各10名,一次性口服4.00 mg 67ZnSO4和1.00mg YbCl3,粪便监测法收集排出粪样;电感耦合等离子体质谱仪(ICP-MS)测定粪样中67Zn/66Zn比值,原子吸收火焰分光光度法(AAS)测定粪样总Zn,计算膳食Zn吸收率.结果 在不同膳食结构下,成年男子Zn表观吸收率为28.4%,真吸收率为30.3%;育龄妇女Zn表观吸收率为26.8%,真吸收率为30.9%.结果 湖南、湖北等省份膳食结构中zn的吸收率高于我国现行Zn的膳食营养参考摄入量(DRIs)(25%的估计值).     

青春前期女童口服铁剂吸收利用的动力学研究

目的探讨青春前期女性儿童铁的利用率情况。方法在常规膳食模式下,以57Fe为示踪剂,27名10~12岁女性儿童为受试对象,分别在口服示踪剂前、14天后和28天后采集静脉血分离红细胞。样品经消化后分别测定其铁含量及同位素丰度,计算并分析受试者57Fe在红细胞中掺入情况。结果 14天和28天红细胞内57Fe与摄入总量比值分别为(19.84±0.53)%和(18.75±0.40)%(P0.05),红细胞内57Fe与全血中57Fe量比值分别为(93.49±2.27)%和(88.73±0.43)%,14天红细胞掺入率显著高于28天时(P0.05)。结论以单标稳定同位素示踪评价青春前期女性儿童红细胞掺入率,可反映受试者体内铁的利用情况。青春前期女性儿童铁的利用率普遍较高,给予示踪剂后14天可作为红细胞掺入率研究的切入点。     

Iron absorption from fish sauce and soy sauce fortified with sodium iron EDTA

BACKGROUND: Fish sauce and soy sauce have been suggested as food vehicles for iron fortification in Asia. NaFeEDTA is a potentially useful fortificant because it can be added to these condiments without causing precipitation during storage. OBJECTIVES: The objectives were to evaluate iron absorption from NaFeEDTA-fortified fish sauce and soy sauce against a reference fortificant (FeSO(4)), to compare iron absorption from NaFeEDTA-fortified fish sauce and soy sauce, and to evaluate the influence of fish sauce and soy sauce per se on iron absorption. DESIGN: Five separate iron-absorption studies were made in adult women (10 women per study). Iron absorption was measured on the basis of erythrocyte incorporation of (57)Fe or (58)Fe 14 d after the intake of labeled meals of rice or rice and vegetables. Fish sauce or soy sauce (10 g) fortified with 5 mg Fe as NaFeEDTA or FeSO(4) was fed with selected meals. The results are presented as geometric means. RESULTS: Iron absorption from NaFeEDTA- and FeSO(4)-fortified fish sauce (3.3% and 3.1%, respectively) and soy sauce (6.1% and 5.6%, respectively) was not significantly different. No significant difference was observed when NaFeEDTA-fortified fish sauce and soy sauce were compared directly (6.7% and 7.9%, respectively). Soy sauce inhibited iron absorption from rice-based meals (8.5% without and 6.0% with soy sauce; P < 0.02), whereas fish sauce did not affect iron absorption significantly. CONCLUSION: The relatively high iron absorption from NaFeEDTA-fortified fish sauce and soy sauce and the acceptable organoleptic properties of NaFeEDTA indicate the potential usefulness of this iron fortificant in fish sauce and soy sauce fortification programs.     

An evaluation of EDTA compounds for iron fortification of cereal-based foods

Fe absorption was measured in adult human subjects consuming different cereal foods fortified with radiolabelled FeSO4, ferrous fumarate or NaFeEDTA, or with radiolabelled FeSO4 or ferric pyrophosphate in combination with different concentrations of Na2EDTA. Mean Fe absorption from wheat, wheat-soyabean and quinoa (Chenopodium quinoa) infant cereals fortified with FeSO4 or ferrous fumarate ranged from 0.6 to 2.2%. For each infant cereal, mean Fe absorption from ferrous fumarate was similar to that from FeSO4 (absorption ratio 0.91-1.28). Mean Fe absorption from FeSO4-fortified bread rolls was 1.0% when made from high-extraction wheat flour and 5.7% when made from low-extraction wheat flour. Fe absorption from infant cereals and bread rolls fortified with NaFeEDTA was 1.9-3.9 times greater than when the same product was fortified with FeSO4. Both high phytate content and consumption of tea decreased Fe absorption from the NaFeEDTA-fortified rolls. When Na2EDTA up to a 1:1 molar ratio (EDTA:Fe) was added to FeSO4-fortified wheat cereal and wheat-soyabean cereal mean Fe absorption from the wheat cereal increased from 1.0% to a maximum of 5.7% at a molar ratio of 0.67:1, and from the wheat-soyabean cereal from 0.7% to a maximum of 2.9% at a molar ratio of 1:1. Adding Na2EDTA to ferric pyrophosphate-fortified wheat cereal did not significantly increase absorption (P > 0.05). We conclude that Fe absorption is higher from cereal foods fortified with NaFeEDTA than when fortified with FeSO4 or ferrous fumarate, and that Na2EDTA can be added to cereal foods to enhance absorption of soluble Fe-fortification compounds such as FeSO4.     

Effects of wheat flour fortified with different iron fortificants on iron status and anemia prevalence in iron deficient anemic students in Northern China

OBJECTIVES: To compare the effects of wheat flours fortified with NaFeEDTA, FeSO4 and elemental iron (electrolytic iron), in improving iron status in anemic students. METHODS: Four hundreds anemic students (11 to 18 years old) were divided into four groups and given wheat flour fortified with different iron fortificants at different concentrations: control group (no added iron); NaFeEDTA group (20 mg Fe/kg); FeSO4 group (30 mg Fe/kg); and elemental iron group (60 mg Fe/kg). The trial lasted for 6 months and the following parameters were examined every 2 months: whole blood hemoglobin, free erythrocyte protoporphyrin, serum ferritin, serum iron, total iron binding capacity and transferrin receptor. RESULTS: The flour consumption in the 4 groups was 300-400 g/person/day, accounted for 70% of total cereal consumption in the diets. There were no significant differences in flour consumption among the 4 groups. Blood hemoglobin level increased in all the 3 intervened groups, but the increment in the NaFeEDTA group was significantly higher and earlier than the other 2 groups; and only 1% of the subjected remained anemic at the end of the trial in the NaFeEDTA group, while 40% and 60% of the subjects in the FeSO4 and electrolytic iron group remained anemic, respectively. The order of improvements in free erythrocyte protoporphyrin, serum ferritin and transferring receptor levels were: NaFeEDTA > FeSO4 > electrolytic iron. No significant changes were found in the control group on all the tested parameters during the trial. CONCLUSIONS: The results indicated that even NaFeEDTA was added at a lower level, it has better effects than FeSO4 and elemental iron on controlling iron deficiency anemia and improving iron status in anemic children; while elemental iron was the least effective.     

Iron absorption during normal human pregnancy: a study using stable isotopes

The absorption of iron has been determined in nine healthy women studied serially during pregnancy and once post delivery. Following the oral administration of 5 mg aqueous 54FeSO4 plus ascorbic acid and the intravenous injection of 200 micrograms 57FeSO4, the isotope ratios of 54Fe: 56Fe and 57Fe: 56Fe in serum were measured by the use of inductively-coupled-plasma mass spectrometry whereby metal ions are vaporized into an argon plasma without previous blood sample preparation. Mean oral Fe absorption was 7.6 (range 1-22)% at 12 weeks gestation, 21.1 (range 9-58)% at 24 weeks, 37.4 (range 18-56)% at 36 weeks and 26.3 (range 8-54)% at 12 weeks post delivery. All the other biochemical and haematological indices were within normal limits for pregnancy. The significant increase (P less than 0.01) in Fe absorption during normal pregnancy suggests that most women would have the potential to meet the Fe demands of pregnancy without the need for supplementation if dietary Fe has similar availability to the aqueous preparation.     

Sodium iron EDTA [NaFe(III)EDTA] as a food fortificant: erythrocyte incorporation of iron and apparent absorption of zinc, copper, calcium, and magnesium from a complementary food based on wheat and soy in healthy infants

BACKGROUND: Phytic acid is a strong inhibitor of iron absorption from fortified foods. In adults, this inhibitory effect can be overcome by adding ascorbic acid with the iron fortificant or by using a "protected" iron compound such as NaFeEDTA. In addition, the use of NaFeEDTA as an iron fortificant has been reported to increase zinc absorption in adult women. No information is available on iron bioavailability from NaFeEDTA or the influence of NaFeEDTA on minerals and trace elements in infants. OBJECTIVE: We aimed to compare iron bioavailability from a complementary food based on wheat and soy fortified with either NaFeEDTA or ferrous sulfate plus ascorbic acid. The apparent absorption of zinc, copper, calcium, and magnesium was evaluated in parallel. DESIGN: Stable-isotope techniques were used in a crossover design to evaluate erythrocyte incorporation of iron 14 d after administration of labeled test meals and the apparent absorption of zinc, copper, calcium, and magnesium on the basis of fecal monitoring in 11 infants. RESULTS: Geometric mean erythrocyte incorporation of iron was 3.7% (NaFeEDTA) and 4.9% (ferrous sulfate plus ascorbic acid) (P = 0.08). No significant differences in the apparent absorption of zinc, copper, calcium, or magnesium were observed between test meals (n = 10). CONCLUSIONS: Iron bioavailability from a high-phytate, cereal-based complementary food fortified with either NaFeEDTA or ferrous sulfate plus ascorbic acid was not significantly different. NaFeEDTA did not influence the apparent absorption of zinc, copper, calcium, or magnesium. NaFeEDTA does not provide any nutritional benefit compared with the combination of a highly bioavailable iron compound and ascorbic acid.     

Fortification iron as ferrous sulfate plus ascorbic acid is more rapidly absorbed than as sodium iron EDTA but neither increases serum nontransferrin-bound iron in women

The absorption profile of iron fortificants may be a determinant of their ability to generate nontransferrin-bound iron (NTBI) and, thus, their potential safety. Ferrous iron may be absorbed more rapidly than chelated ferric iron, but differences at the fortification level cannot be distinguished with nonisotopically labeled serum iron curves. Using stable isotope appearance curves (SIAC) in serum, we measured iron absorption profiles from FeSO(4) with ascorbic acid (AA) and from NaFeEDTA, as well as the serum hepcidin and NTBI response following the meals. Healthy women (n = 16) were given 6 mg oral iron as labeled FeSO(4) and NaFeEDTA with a maize porridge using a crossover design. SIAC, NTBI, and serum hepcidin were measured over 8 h after the meal. Iron from FeSO(4) plus AA was more rapidly absorbed, resulting in a 35% greater relative AUC during the first 2 h than for NaFeEDTA (P < 0.001). Median (95% CI) fractional iron absorption from the FeSO(4)- and NaFeEDTA-fortified meals was 15.2% (11.0-19.5) and 6.0% (5.0-9.2), respectively (P < 0.001). In response to the FeSO(4)-fortified meal, there was an ~60% increase in median serum hepcidin (P < 0.05) but no significant change in NTBI. There was no significant change in serum hepcidin or NTBI after the NaFeEDTA-fortified meal. SIAC are a useful new tool to compare iron absorption profiles from different iron compounds in fortified foods. Even with the use of a very well absorbed ferrous iron compound, iron fortification in this population does not increase NTBI, suggesting a low risk for adverse health consequences.     

Sodium iron NaFeEDTA as an iron fortification compound in Central America. Absorption studies.

Studies were performed in seven children and 98 adults to compare the proportion of iron absorbed when administered as ferric sulfate (Fe2(SO4)3), NaFeEDTA, hemoglobin (Hb), and ferrous ascorbate. Studies in children (mostly iron deficient) showed that when the compounds were given with a milk-rice-sugar formula totalling 5 mg Fe, iron from hemoglobin was absorbed best, followed by NaFeEDTA and by Fe2(SO4)3 (mean percent absorption +/-SD = 34.5 +/- 1.5, 8.6 +/- 1.9 and 3.3 +/- 1.5, respectively). Studies in normal or iron deficient adults also demonstrated a better absorption of iron from NaFeEDTA than from Fe2(SO4)3 whether these compounds were given in an aqueous solution (5 mg Fe) or with a standard meal consisting of beans, tortillas, bread, and coffee providing also a total of 5 mg Fe. Hb iron under the same conditions was absorbed in the same proportion to the reference iron ascorbate, always being higher than iron absorbed from the other compounds. Fe2(SO4)3 and NaFeEDTA mixed in the same meal were absorbed in the same proportion as when NaFeEDTA alone was added to the meal and 2 to 3 times better than when Fe2(SO4)3 alone was added to the meal. Addition of desferrioxamine depressed iron absorption from Fe2(SO4)3 and NaFeEDTA, the latter being less affected. Addition of ascorbic acid increased absorption from both. When the compounds were added to the meal to provide 50 mg of iron, percent absorption was depressed in relation to the smaller iron dose in the case of Fe2(SO4)3 and Hb but remained unaltered in the case of NaFeEDTA. Addition of 45 mg Fe as Fe2(SO4)3 or NaFeEDTA to 0.4 mg Fe from the Hb in the meal did not change Hb iron absorption. Addition of 45 mg Fe as Hb or NaFeEDTA to 0.4 mg Fe from Fe2(SO4)3 in the meal enhanced iron absorption from the latter in the same proportions. Addition of 45 mg Fe as Fe2(SO4)3 and Hb to 0.4 mg Fe as NaFeEDTA in the meal respectively depressed and enhanced iron absorption from NaFeEDTA. These studies indicate that NaFeEDTA, Fe2(SO4)3 and nonheme food iron from a common pool different from the heme pool but which is changed in its characteristics by the presence of NaFeEDTA, resulting in a better absorption of iron.