McKay Alannah K A, Peeling Peter, Pyne David B, Tee Nicolin, Welveart Marijke, Heikura Ida A, Sharma Avish P, Whitfield Jamie, Ross Megan L, van Swelm Rachel P L, Laarakkers Coby M, Burke Louise M
The University of Western Australia.
Western Australian Institute of Sport.
Int J Sport Nutr Exerc Metab. 2021 Mar 1;31(2):101-108. doi: 10.1123/ijsnem.2020-0224. Epub 2021 Dec 31.
This study implemented a 2-week high carbohydrate (CHO) diet intended to maximize CHO oxidation rates and examined the iron-regulatory response to a 26-km race walking effort. Twenty international-level, male race walkers were assigned to either a novel high CHO diet (MAX = 10 g/kg body mass CHO daily) inclusive of gut-training strategies, or a moderate CHO control diet (CON = 6 g/kg body mass CHO daily) for a 2-week training period. The athletes completed a 26-km race walking test protocol before and after the dietary intervention. Venous blood samples were collected pre-, post-, and 3 hr postexercise and measured for serum ferritin, interleukin-6, and hepcidin-25 concentrations. Similar decreases in serum ferritin (17-23%) occurred postintervention in MAX and CON. At the baseline, CON had a greater postexercise increase in interleukin-6 levels after 26 km of walking (20.1-fold, 95% CI [9.2, 35.7]) compared with MAX (10.2-fold, 95% CI [3.7, 18.7]). A similar finding was evident for hepcidin levels 3 hr postexercise (CON = 10.8-fold, 95% CI [4.8, 21.2]; MAX = 8.8-fold, 95% CI [3.9, 16.4]). Postintervention, there were no substantial differences in the interleukin-6 response (CON = 13.6-fold, 95% CI [9.2, 20.5]; MAX = 11.2-fold, 95% CI [6.5, 21.3]) or hepcidin levels (CON = 7.1-fold, 95% CI [2.1, 15.4]; MAX = 6.3-fold, 95% CI [1.8, 14.6]) between the dietary groups. Higher resting serum ferritin (p = .004) and hotter trial ambient temperatures (p = .014) were associated with greater hepcidin levels 3 hr postexercise. Very high CHO diets employed by endurance athletes to increase CHO oxidation have little impact on iron regulation in elite athletes. It appears that variations in serum ferritin concentration and ambient temperature, rather than dietary CHO, are associated with increased hepcidin concentrations 3 hr postexercise.
本研究实施了为期2周的高碳水化合物（CHO）饮食，旨在使CHO氧化率最大化，并研究了对26公里竞走运动的铁调节反应。20名国际水平的男性竞走运动员被分配到一种新型的高CHO饮食组（MAX =每日10克/千克体重的CHO），该饮食包括肠道训练策略，或中等CHO对照饮食组（CON =每日6克/千克体重的CHO），为期2周的训练期。运动员在饮食干预前后完成了一项26公里的竞走测试方案。在运动前、运动后和运动后3小时采集静脉血样，测量血清铁蛋白、白细胞介素-6和铁调素-25的浓度。MAX组和CON组在干预后血清铁蛋白均有相似程度的下降（17 - 23%）。在基线时，与MAX组（10.2倍，95%可信区间[3.7, 18.7]）相比，CON组在行走26公里后运动后白细胞介素-6水平升高幅度更大（20.1倍，95%可信区间[9.2, 35.7]）。运动后3小时铁调素水平也有类似发现（CON组 = 10.8倍，95%可信区间[4.8, 21.2]；MAX组 = 8.8倍，95%可信区间[3.9, 16.4]）。干预后，饮食组之间白细胞介素-6反应（CON组 = 13.6倍，95%可信区间[9.2, 20.5]；MAX组 = 11.2倍，95%可信区间[6.5, 21.3]）或铁调素水平（CON组 = 7.1倍，95%可信区间[2.1, 15.4]；MAX组 = 6.3倍，95%可信区间[1.8, 14.6]）没有实质性差异。较高的静息血清铁蛋白（p = 0.004）和更高的试验环境温度（p = 0.014）与运动后3小时更高的铁调素水平相关。耐力运动员采用的超高CHO饮食以增加CHO氧化，对精英运动员的铁调节影响很小。似乎血清铁蛋白浓度和环境温度的变化，而非饮食中的CHO，与运动后3小时铁调素浓度升高有关。
