Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.
Am J Clin Nutr. 2010 Nov;92(5):1071-9. doi: 10.3945/ajcn.2010.29566. Epub 2010 Sep 8.
When fructose is ingested together with glucose (GLUFRU) during exercise, plasma lactate and exogenous carbohydrate oxidation rates are higher than with glucose alone.
The objective was to investigate to what extent GLUFRU increased lactate kinetics and oxidation rate and gluconeogenesis from lactate (GNG(L)) and from fructose (GNG(F)).
Seven endurance-trained men performed 120 min of exercise at ≈60% VO₂max (maximal oxygen consumption) while ingesting 1.2 g glucose/min + 0.8 g of either glucose or fructose/min (GLUFRU). In 2 trials, the effects of glucose and GLUFRU on lactate and glucose kinetics were investigated with glucose and lactate tracers. In a third trial, labeled fructose was added to GLUFRU to assess fructose disposal.
In GLUFRU, lactate appearance (120 ± 6 μmol · kg⁻¹ · min⁻¹), lactate disappearance (121 ± 7 μmol · kg⁻¹ · min⁻¹), and oxidation (127 ± 12 μmol · kg⁻¹ · min⁻¹) rates increased significantly (P < 0.001) in comparison with glucose alone (94 ± 16, 95 ± 16, and 97 ± 16 μmol · kg⁻¹ · min⁻¹, respectively). GNG(L) was negligible in both conditions. In GLUFRU, GNG(F) and exogenous fructose oxidation increased with time and leveled off at 18.8 ± 3.7 and 38 ± 4 μmol · kg⁻¹ · min⁻¹, respectively, at 100 min. Plasma glucose appearance rate was significantly higher (P < 0.01) in GLUFRU (91 ± 6 μmol · kg⁻¹ · min⁻¹) than in glucose alone (82 ± 9 μmol · kg⁻¹ · min⁻¹). Carbohydrate oxidation rate was higher (P < 0.05) in GLUFRU.
Fructose increased total carbohydrate oxidation, lactate production and oxidation, and GNG(F). Fructose oxidation was explained equally by fructose-derived lactate and glucose oxidation, most likely in skeletal and cardiac muscle. This trial was registered at clinicaltrials.gov as NCT01128647.
当果糖与葡萄糖（GLUFRU）一起在运动中摄入时，血浆乳酸和外源性碳水化合物氧化率高于单独使用葡萄糖时。
目的是研究 GLUFRU 对乳酸动力学和氧化率以及乳酸（GNG（L））和果糖（GNG（F））的糖异生有多大程度的影响。
七名耐力训练的男性以约 60%的 VO₂max（最大摄氧量）进行 120 分钟的运动，同时以 1.2 g/min 的速度摄入葡萄糖和 0.8 g/min 的葡萄糖或果糖（GLUFRU）。在 2 项试验中，用葡萄糖和乳酸示踪剂研究了葡萄糖和 GLUFRU 对乳酸和葡萄糖动力学的影响。在第三次试验中，将标记的果糖添加到 GLUFRU 中以评估果糖的处置。
在 GLUFRU 中，与单独使用葡萄糖相比，乳酸出现率（120±6 μmol·kg⁻¹·min⁻¹）、乳酸消失率（121±7 μmol·kg⁻¹·min⁻¹）和氧化率（127±12 μmol·kg⁻¹·min⁻¹）显著增加（P<0.001）。在两种情况下，GNG（L）都可以忽略不计。在 GLUFRU 中，GNG（F）和外源性果糖氧化随着时间的推移而增加，并在 100 分钟时分别稳定在 18.8±3.7 和 38±4 μmol·kg⁻¹·min⁻¹。GLUFRU 中的血浆葡萄糖出现率明显高于单独使用葡萄糖（91±6 μmol·kg⁻¹·min⁻¹）（P<0.01）。碳水化合物氧化率在 GLUFRU 中更高（P<0.05）。
果糖增加了总碳水化合物氧化、乳酸生成和氧化以及 GNG（F）。果糖氧化由果糖衍生的乳酸和葡萄糖氧化解释，这很可能发生在骨骼肌和心肌中。本试验在 clinicaltrials.gov 上注册为 NCT01128647。
