Acute carbohydrate ingestion does not influence the post-exercise iron-regulatory response in elite keto-adapted race walkers. Issue 6 (June 2019)

• Record Type: Journal Article
• Authors: McKay, Alannah K.A.; Peeling, Peter; Pyne, David B.; Welvaert, Marijke; Tee, Nicolin; Leckey, Jill J.; Sharma, Avish P.; Ross, Megan L.R.; Garvican-Lewis, Laura A.; van Swelm, Rachel P.L.; Laarakkers, Coby M.; Burke, Louise M.
• Is Part Of: Journal of science and medicine in sport. Volume 22:Issue 6(2019)
• Page Start: 635
• Page End: 640
• Publication Date: 2019-06
• Subjects: LCHF diet -- Iron metabolism -- Ferritin -- Hepcidin -- Interleukin-6 -- Race-walkers; Sports sciences -- Periodicals; Sports medicine -- Periodicals; Exercise -- Physiological aspects -- Periodicals; Sports -- physiology -- Periodicals; Sports Medicine -- Periodicals; Sportgeneeskunde; 617.102705
• DOI: 10.1016/j.jsams.2018.12.015
• Languages: English
• ISSNs: 1440-2440

Abstract

Abstract: Objectives: 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. Design: Parallel groups design. Methods: 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 19–25 km 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 3 h post-exercise and measured for interleukin-6 (IL-6) and hepcidin-25. Results: 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 3 h post-exercise (p < 0.001), however, they did not differ between trials (p = 0.46) or diets (p = 0.84). Conclusions: 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.