Laboratory of Human Nutrition, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland.
Laboratory of Human Nutrition, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland; Department of Physiology and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.
Am J Clin Nutr. 2023 Jan;117(1):64-72. doi: 10.1016/j.ajcnut.2022.10.005. Epub 2022 Dec 15.
Whether prebiotic human milk oligosaccharides (HMO), such as 2'-fucosyllactose (2'-FL) and lacto-N-neotetraose (LNnT), enhance iron absorption in infants is unknown. Moreover, whether maternal HMO profile affects absorption of iron fortificants or the effects of prebiotic galacto-oligosaccharides (GOS) and/or HMO on iron absorption is uncertain.
The aim of this study was to test whether consumption of 3.0 g GOS or HMO enhances iron absorption from iron-fortified maize porridge in partially breastfed Kenyan infants and whether maternal HMO profile modulates these effects.
In a randomized, prospective crossover study, 55 infants (aged 8-12 mo) were fed test meals fortified with 1 of the following: 1) 5.0 mg iron as Fe-labeled ferrous fumarate (FeFum); 2) 5.0 mg iron as FeFum and 3.0 g GOS (FeFum+GOS); and 3) 5.0 mg iron as FeFum and 2.0 g 2'-FL and 1.0 g LNnT (FeFum+HMO). Fractional iron absorption (FIA) was assessed by erythrocyte incorporation of iron isotopes. HMO profiles were determined by capillary gel electrophoresis with laser-induced florescence detection. Data were analyzed with mixed-effect models, and iron dialyzability was measured in vitro.
Of the 55 infants included, 49 were fed as instructed. FIA from the FeFum+GOS group [median (IQR) 22.2% (16.5%-25.9%)] was higher than that from the FeFum group [12.5% (9.5%-20.9%)] (P = 0.005). FIA from the FeFum+HMO group was 13.3% (7.1%-24.4%) and did not differ from the FeFum group (P = 0.923). Maternal HMO profile did not predict FIA or modulate the effects of GOS or HMO on FIA. Iron dialyzability ratios at pH 2 of FeFum+GOS to FeFum and FeFum+HMO to FeFum were 2.1 and 0.9 (P = 0.001 and P = 0.322), respectively.
In Kenyan infants consuming FeFum-fortified maize porridge, co-provision of 3.0 g GOS increased FIA by 78%, whereas co-provision of 3.0 g HMO did not affect FIA. Variations in maternal HMO profile, including secretor and Lewis phenotype, did not predict FIA. These data argue against a physiologic role for 2'-FL and LNnT in facilitating iron absorption in infancy. The study was registered at clinicaltrials.gov as NCT04163406 (https://clinicaltrials.gov/ct2/show/NCT04163406).
目前尚不清楚母乳低聚糖（HMO）等益生元是否能增强婴儿对铁的吸收，例如 2'-岩藻糖基乳糖（2'-FL）和乳-N-新四糖（LNnT）。此外，母体 HMO 谱是否会影响铁强化剂的吸收，以及是否益生元半乳糖-低聚糖（GOS）和/或 HMO 对铁吸收有影响，这些都不确定。
本研究旨在测试 3.0 g GOS 或 HMO 是否能增强肯尼亚部分母乳喂养婴儿对铁强化玉米粥中铁的吸收，并测试母体 HMO 谱是否会调节这些影响。
在一项随机、前瞻性交叉研究中，55 名 8-12 月龄婴儿食用了以下 1 种强化铁的测试餐食：1）5.0 mg 铁作为 Fe 标记富马酸亚铁（FeFum）；2）5.0 mg 铁作为 FeFum 和 3.0 g GOS（FeFum+GOS）；和 3）5.0 mg 铁作为 FeFum 和 2.0 g 2'-FL 和 1.0 g LNnT（FeFum+HMO）。通过红细胞掺入铁同位素来评估铁的分数吸收率（FIA）。采用毛细管凝胶电泳结合激光诱导荧光检测法测定 HMO 谱。采用混合效应模型进行数据分析，并在体外测量铁的可透析性。
在纳入的 55 名婴儿中，有 49 名按要求接受了喂养。与 FeFum 组相比，FeFum+GOS 组的 FIA [中位数（IQR）22.2%（16.5%-25.9%）]更高（P=0.005）。FeFum+HMO 组的 FIA 为 13.3%（7.1%-24.4%），与 FeFum 组无差异（P=0.923）。母体 HMO 谱并不能预测 FIA，也不能调节 GOS 或 HMO 对 FIA 的影响。FeFum+GOS 与 FeFum 和 FeFum+HMO 与 FeFum 在 pH 2 时的铁可透析率分别为 2.1 和 0.9（P=0.001 和 P=0.322）。
在肯尼亚食用铁强化玉米粥的婴儿中，同时提供 3.0 g GOS 可使 FIA 增加 78%，而同时提供 3.0 g HMO 则不会影响 FIA。母体 HMO 谱的变化，包括分泌型和 Lewis 表型，并不预示 FIA。这些数据表明，2'-FL 和 LNnT 在促进婴儿铁吸收方面没有生理作用。该研究在 clinicaltrials.gov 上注册为 NCT04163406（https://clinicaltrials.gov/ct2/show/NCT04163406）。
