Author(s): HAYASHI, N., YAMADA, M., ISHIKAWA, A., KAMEMOTO, K., OKAZAKI, K., SAKAMAKI-SUNAGA, M., Institution: OSAKA METROPOLITAN UNIVERSITY, Country: JAPAN, Abstract-ID: 2023

INTRODUCTION:
Hepcidin, an iron-regulating hormone, is thought to be downregulated by stimuli that promote erythropoiesis (Nemeth & Ganz, 2023). Ketosis, characterized by elevated β-hydroxybutyrate (βHB) levels, was reported to increase post-exercise serum erythropoietin (EPO) concentration following acute ketone supplementation in healthy men (Evans et al., 2023). Therefore, this study aimed to investigate the effects of βHB supplementation after exercise on EPO and hepcidin responses in active women.
METHODS:
Eight women completed the experimental trials [means ± SD, age: 20 ± 1 years, height: 155.8 ± 7.9 cm, body mass (BM): 54.9 ± 6.2 kg, peak oxygen consumption (VO2peak): 45.7 ± 4.3 mL/kg/min] under two different conditions during the early-follicular phase: either consuming 25.5 g of βHB (8.5 g/h, 3 times; βHB) or an equivalent amount of placebo (CON) after high-intensity interval exercise (3-minutes warm-up, 8 sets of 3-minutes cycling at 85%VO2peak, 3-minutes cool-down). The βHB/placebo supplements (OKETOA®, Osaka Gas Co., Ltd.) were consumed immediately, 60 min and 120 min after exercise. A light meal (0.9 g/kg BM of carbohydrate, 0.1 g/kg BM of protein) was consumed with βHB/placebo supplements 60 min after exercise. Blood samples were collected before and after exercise (0, 30, 120, and 180 min); respiratory samples with a breath-by-breath method were collected before and after exercise (30, 120, and 180 min). A repeated-measures two-way ANOVA was applied, and significant interactions or main effects were followed up using Bonferroni post-hoc test. Significance was set at p < 0.05.
RESULTS:
Significant differences were observed in serum βHB responses (F = 43.523, p < 0.001). Serum βHB concentrations were significantly higher in the βHB trial than in the CON trial (30 min: p = 0.004, 60 min: p = 0.004, 120 min: p = 0.006, 180 min: p = 0.028). The βHB trial showed a significantly lower mean blood glucose concentration than the CON trial (F = 11.372, p = 0.012). Significant differences were observed in changes in the respiratory exchange ratio (RER; F = 3.994, p = 0.011). The βHB trial exhibited a significantly lower RER 120 min after exercise than in the CON trial (p = 0.002). No significant differences were observed in serum hepcidin response between the trials (F = 0.714, p = 0.427). Significant differences were observed in serum EPO response between the trials (F = 7.595, p = 0.020); however, the post-hoc test did not reveal significant differences between the trials. Changes in serum EPO concentration (180 min minus pre-exercise) were significantly different between the trials (βHB: + 0.325 ± 0.974 mIU/mL, CON: -1.325 ± 1.400 mIU/mL; p = 0.027).
CONCLUSION:
Exogenous ketosis via βHB supplementation influenced the EPO response and glucose metabolism but did not affect the hepcidin response following high-intensity interval exercise.