School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Australia; Australian Institute of Sport, Australia; Western Australian Institute of Sport, Australia.
School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Australia; Western Australian Institute of Sport, Australia.
J Sci Med Sport. 2019 Jun;22(6):635-640. doi: 10.1016/j.jsams.2018.12.015. Epub 2019 Jan 4.
Adhering to a low carbohydrate (CHO) high fat (LCHF) diet can alter markers of iron metabolism in endurance athletes. This investigation examined the re-introduction of CHO prior to, and during exercise on the iron-regulatory response to exercise in a homogenous (in regard to serum ferritin concentration) group of athletes adapted to a LCHF diet.
Parallel groups design.
Three weeks prior to the exercise trials, twenty-three elite race walkers adhered to either a CHO-rich (n=14) or LCHF diet (n=9). A standardised 19-25km race walk was performed while athletes were still adhering to their allocated dietary intervention (Adapt). A second test was performed three days later, where all athletes were placed on a high CHO diet (CHO Restoration). Venous blood samples were collected pre-, post- and 3h post-exercise and measured for interleukin-6 (IL-6) and hepcidin-25.
The post-exercise IL-6 increase was greater in LCHF (p<0.001) during both the Adapt (LCHF: 13.1-fold increase; 95% CI: 5.6-23.0, CHO: 8.0-fold increase; 5.1-11.1) and CHO Restoration trials (LCHF: 18.5-fold increase; 10.9-28.9, CHO: 6.3-fold increase; 3.9-9.5); outcomes were not different between trials (p=0.84). Hepcidin-25 concentrations increased 3h post-exercise (p<0.001), however, they did not differ between trials (p=0.46) or diets (p=0.84).
The elevated IL-6 response in athletes adapted to a LCHF diet was not attenuated by an acute increase in exogenous CHO availability. Despite diet-induced differences in IL-6 response to exercise, post-exercise hepcidin levels were similar between diets and trials, indicating CHO availability has minimal influence on post-exercise iron metabolism.
坚持低碳水化合物（CHO）高脂肪（LCHF）饮食可以改变耐力运动员铁代谢的标志物。本研究调查了在适应 LCHF 饮食的同质（血清铁蛋白浓度方面）运动员群体中，在运动前和运动期间重新引入 CHO 对运动引起的铁调节反应的影响。
平行组设计。
在进行运动试验前的 3 周，23 名精英竞走运动员分别遵循富含 CHO（n=14）或 LCHF 饮食（n=9）。在运动员仍遵循其分配的饮食干预（适应）时，进行了标准化的 19-25km 竞走。三天后进行了第二次测试，所有运动员都采用高 CHO 饮食（CHO 恢复）。在运动前、运动后和运动后 3 小时采集静脉血样，并测量白细胞介素-6（IL-6）和hepcidin-25。
在适应（LCHF：增加 13.1 倍；95%CI：5.6-23.0，CHO：增加 8.0 倍；5.1-11.1）和 CHO 恢复试验（LCHF：增加 18.5 倍；10.9-28.9，CHO：增加 6.3 倍；3.9-9.5）中，LCHF 组的运动后 IL-6 增加更大（p<0.001）；试验之间的结果没有差异（p=0.84）。hepcidin-25 浓度在运动后 3 小时升高（p<0.001），但试验之间（p=0.46）或饮食之间（p=0.84）没有差异。
适应 LCHF 饮食的运动员中升高的 IL-6 反应并未因外源性 CHO 供应的急性增加而减弱。尽管运动引起的 IL-6 对运动的反应存在饮食差异，但运动后 hepcidin 水平在饮食和试验之间相似，表明 CHO 供应对运动后铁代谢的影响很小。
