Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, MA, United States.
Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, MA, United States; Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States.
J Nutr. 2023 Jun;153(6):1696-1709. doi: 10.1016/j.tjnut.2023.03.002. Epub 2023 Mar 8.
Increasing β-hydroxybutyrate (βHB) availability through ketone monoester (KE) plus carbohydrate supplementation is suggested to enhance physical performance by sparing glucose use during exercise. However, no studies have examined the effect of ketone supplementation on glucose kinetics during exercise.
This exploratory study primarily aimed to determine the effect of KE plus carbohydrate supplementation on glucose oxidation during steady-state exercise and physical performance compared with carbohydrate alone.
Using a randomly assigned, crossover design, 12 men consumed 573 mg KE/kg body mass plus 110 g glucose (KE+CHO) or 110 g glucose (CHO) before and during 90 min of steady-state treadmill exercise [54 ± 3% peak oxygen uptake (V˙O)] wearing a weighted vest (30% body mass; 25 ± 3 kg). Glucose oxidation and turnover were determined using indirect calorimetry and stable isotopes. Participants performed an unweighted time to exhaustion (TTE; 85% V˙O) after steady-state exercise and a weighted (25 ± 3 kg) 6.4 km time trial (TT) the next day after consuming a bolus of KE+CHO or CHO. Data were analyzed by paired t-tests and mixed model ANOVA.
βHB concentrations were higher (P < 0.05) after exercise [2.1 mM (95% CI: 1.6, .6)] and the TT [2.6 mM (2.1, 3.1)] in KE+CHO compared with CHO. TTE was lower [-104 s (-201, -8)], and TT performance was slower [141 s (19,262)] in KE+CHO than in CHO (P < 0.05). Exogenous [-0.01 g/min (-0.07, 0.04)] and plasma [-0.02 g/min (-0.08, 0.04)] glucose oxidation and metabolic clearance rate {MCR [0.38 mg·kg·min (-0.79, 1.54)]} were not different, and glucose rate of appearance [-0.51 mg·kg·min (-0.97, -0.04)], and disappearance [-0.50 mg·kg·min (-0.96, -0.04)] were lower (P < 0.05) in KE+CHO compared with CHO during steady-state exercise.
In the current study, rates of exogenous and plasma glucose oxidation and MCR were not different between treatments during steady-state exercise, suggesting blood glucose utilization is similar between KE+CHO and CHO. KE+CHO supplementation also results in lower physical performance compared with CHO alone. This trial was registered at www.
gov as NCT04737694.
通过酮单酯 (KE) 加碳水化合物补充来增加 β-羟基丁酸 (βHB) 的可用性，被认为可以通过在运动中节省葡萄糖的使用来提高身体表现。然而，尚无研究检查酮补充对运动期间葡萄糖动力学的影响。
本探索性研究主要旨在确定与单独补充碳水化合物相比，KE 加碳水化合物补充对稳态运动期间葡萄糖氧化和身体表现的影响。
使用随机分配、交叉设计，12 名男性在穿着负重背心（体重的 30%；25 ± 3 公斤）进行 90 分钟稳态跑步机运动[54 ± 3% 峰值摄氧量 (V˙O)]之前和期间，分别摄入 573 mg KE/kg 体重和 110 g 葡萄糖 (KE+CHO) 或 110 g 葡萄糖 (CHO)。使用间接测热法和稳定同位素测定葡萄糖氧化和周转率。在稳态运动后，参与者进行无负重力竭时间测试 (TTE；85% V˙O)，并在摄入 KE+CHO 或 CHO 后的第二天进行负重 (25 ± 3 公斤) 6.4 公里计时赛 (TT)。数据通过配对 t 检验和混合模型方差分析进行分析。
与 CHO 相比，KE+CHO 中的 βHB 浓度在运动后[2.1 mM（95%CI：1.6，.6）]和 TT [2.6 mM（2.1，3.1）]更高（P < 0.05）。TTE 较低[-104 s (-201，-8)]，TT 表现较慢[141 s (19，262)]在 KE+CHO 中比在 CHO 中（P < 0.05）。外源性[-0.01 g/min (-0.07，0.04)]和血浆[-0.02 g/min (-0.08，0.04)]葡萄糖氧化和代谢清除率{MCR [0.38 mg·kg·min (-0.79，1.54)]}没有差异，葡萄糖出现率[-0.51 mg·kg·min (-0.97，-0.04)]和消失率[-0.50 mg·kg·min (-0.96，-0.04)]在 KE+CHO 中比在 CHO 中更低（P < 0.05）在稳态运动期间。
在当前研究中，KE+CHO 和 CHO 之间在稳态运动期间的外源性和血浆葡萄糖氧化和 MCR 速率没有差异，表明血糖利用在 KE+CHO 和 CHO 之间相似。与单独补充 CHO 相比，KE+CHO 补充还会导致身体表现降低。本试验已在 www.clinicaltrials.gov 上注册，编号为 NCT04737694。
