Pompano Laura M, Haas Jere D
Division of Nutritional Sciences, Cornell University, Ithaca, NY
Division of Nutritional Sciences, Cornell University, Ithaca, NY.
Am J Clin Nutr. 2017 Dec;106(6):1529-1538. doi: 10.3945/ajcn.117.152777. Epub 2017 Nov 1.
Despite its known detrimental effects, iron deficiency remains the most common micronutrient deficiency in the world. Many interventions that aim to improve iron status involve physically active populations. Intense aerobic exercise training negatively affects iron status; however, the impact of regular moderate aerobic exercise on the effectiveness of iron supplementation remains unclear. This study aimed to determine whether aerobic training modifies the assessment of the effectiveness of iron supplementation in improving conventional iron status measures. Seventy-two iron-depleted, nonanemic Chinese women [serum ferritin (sFer) <25 μg/L and hemoglobin >110 g/L] were included in an 8-wk, partially blinded, randomized controlled trial with a 2 × 2 factorial design including iron supplements (42 mg elemental Fe/d) or placebo and aerobic training (five 25-min sessions/wk at 75-85% of maximum heart rate) or no training. Linear mixed models were used to evaluate the relation between supplement type, training, and changes in iron status over time, measured by sFer, hemoglobin, soluble transferrin receptor (sTfR), and estimated total body iron. After treatment, both the iron-supplemented trained and untrained groups showed significantly improved sFer, sTfR, and body iron values compared with either of the placebo groups. Similarly, trained participants had significantly higher aerobic fitness measures than untrained participants. Training modified the sFer response to supplementation (training by supplement interaction, = 0.07), with the iron-supplemented trained group having significantly lower sFer than the iron-supplemented untrained group at week 8 (mean ± SD: 31.8 ± 13.5 and 47.6 ± 15.7 μg/L, respectively; = 0.042), whereas there was no significant difference between the placebo trained and untrained groups (21.3 ± 12.2 and 20.3 ± 7.0 μg/L, respectively; = 1.00). Regular aerobic training reduces the apparent effectiveness of iron supplementation in improving sFer and calls into question whether conventional measures of iron status accurately reflect iron metabolism in physically active, nonanemic women. This trial was registered at clinicaltrials.gov as NCT03002090.
尽管缺铁已知有不良影响，但它仍是全球最常见的微量营养素缺乏症。许多旨在改善铁状态的干预措施都涉及身体活跃的人群。高强度有氧运动训练会对铁状态产生负面影响；然而，常规适度有氧运动对铁补充剂效果的影响仍不清楚。本研究旨在确定有氧训练是否会改变对铁补充剂在改善传统铁状态指标方面效果的评估。72名缺铁性非贫血中国女性[血清铁蛋白（sFer）<25μg/L且血红蛋白>110g/L]被纳入一项为期8周的部分盲法随机对照试验，采用2×2析因设计，包括铁补充剂（42mg元素铁/天）或安慰剂以及有氧训练（每周5次，每次25分钟，心率达到最大心率的75 - 85%）或无训练。使用线性混合模型来评估补充剂类型、训练与铁状态随时间变化之间的关系，铁状态通过sFer、血红蛋白、可溶性转铁蛋白受体（sTfR）和估计的全身铁含量来衡量。治疗后，与任何一个安慰剂组相比，补充铁剂的训练组和未训练组的sFer、sTfR和身体铁含量值均显著改善。同样，训练参与者的有氧适能指标显著高于未训练参与者。训练改变了sFer对补充剂的反应（训练与补充剂的交互作用，P = 0.07），在第8周时，补充铁剂的训练组的sFer显著低于补充铁剂的未训练组（均值±标准差：分别为31.8±13.5和47.6±15.7μg/L；P = 0.042），而安慰剂训练组和未训练组之间无显著差异（分别为21.3±12.2和20.3±7.0μg/L；P = 1.00）。常规有氧训练会降低铁补充剂在改善sFer方面的明显效果，并使人质疑传统的铁状态指标是否能准确反映身体活跃的非贫血女性中的铁代谢情况。该试验已在clinicaltrials.gov上注册，注册号为NCT03002090。
