School of Sport and Exercise, Massey University, Wellington, New Zealand.
Med Sci Sports Exerc. 2013 Sep;45(9):1814-24. doi: 10.1249/MSS.0b013e31828e12d4.
Fructose coingested with glucose in carbohydrate (CHO) drinks increases exogenous-CHO oxidation, gut comfort, and physical performance.
This study aimed to determine the effect of different fructose-maltodextrin-glucose ratios on CHO oxidation and fluid absorption while controlling for osmolality and caloricity.
In a crossover design, 12 male cyclists rode 2 h at 57% peak power then performed 10 sprints while ingesting artificially sweetened water or three equiosmotic 11.25% CHO-salt drinks at 200 mL·15 min, comprising weighed fructose and maltodextrin-glucose in ratios of 0.5:1 (0.5 ratio), 0.8:1 (0.8 ratio), and 1.25:1 (1.25 ratio). Fluid absorption was traced with D2O, whereas C-fructose and C-maltodextrin-glucose permitted fructose and glucose oxidation rate evaluation.
The mean exogenous-fructose and exogenous-glucose oxidation rates were 0.27, 0.39, and 0.46 g·min and 0.65, 0.71, and 0.58 g·min in 0.5, 0.8, and 1.25 ratio drinks, representing mean oxidation efficiencies of 54%, 59%, and 55% and 65%, 85%, and 86% for fructose and glucose, respectively. With the 0.8 ratio drink, total exogenous-CHO oxidation rate was 18% (90% confidence interval, ±5%) and 5.2% (±4.6%) higher relative to 0.5 and 1.25 ratios, respectively, whereas respective differences in total exogenous-CHO oxidation efficiency were 17% (±5%) and 5.3% (±4.8%), associated with 8.6% and 7.8% (±4.2%) higher fructose oxidation efficiency. The effects of CHO ratio on water absorption were inconclusive. Mean sprint power with the 0.8 ratio drink was moderately higher than that with the 0.5 ratio (2.9%; 99% confidence interval, ±2.8%) and 1.25 ratio (3.1%; ±2.7%) drinks, with total- and endogenous-CHO oxidation rate, abdominal cramps, and drink sweetness qualifying as explanatory mechanisms.
Enhanced high-intensity endurance performance with a 0.8 ratio fructose-maltodextrin-glucose drink is characterized by higher exogenous-CHO oxidation efficiency and reduced endogenous-CHO oxidation. The gut-hepatic or other physiological site responsible requires further research.
在碳水化合物（CHO）饮料中与葡萄糖共同摄入果糖会增加外源性 CHO 的氧化、肠道舒适度和身体表现。
本研究旨在确定不同果糖-麦芽糊精-葡萄糖比例对 CHO 氧化和液体吸收的影响，同时控制渗透压和热量。
采用交叉设计，12 名男性自行车运动员以 57%的峰值功率骑行 2 小时，然后在摄入人工甜味水或三种等渗 11.25%CHO-盐饮料时进行 10 次冲刺，每 200 毫升 15 分钟摄入称重的果糖和麦芽糊精-葡萄糖，比例为 0.5:1（0.5 比例）、0.8:1（0.8 比例）和 1.25:1（1.25 比例）。用 D2O 追踪液体吸收，而 C-果糖和 C-麦芽糊精-葡萄糖则允许评估果糖和葡萄糖的氧化速率。
在 0.5、0.8 和 1.25 比例的饮料中，外源性果糖和外源性葡萄糖的平均氧化速率分别为 0.27、0.39 和 0.46 g·min 和 0.65、0.71 和 0.58 g·min，分别代表果糖和葡萄糖的平均氧化效率为 54%、59%和 55%和 65%、85%和 86%。与 0.5 和 1.25 比例相比，0.8 比例饮料的总外源性 CHO 氧化速率分别高 18%（99%置信区间，±5%）和 5.2%（±4.6%），而总外源性 CHO 氧化效率的相应差异分别为 17%（±5%）和 5.3%（±4.8%），与果糖氧化效率分别高 8.6%和 7.8%（±4.2%）相关。CHO 比例对水吸收的影响尚无定论。与 0.5 比例（2.9%；99%置信区间，±2.8%）和 1.25 比例（3.1%；±2.7%）饮料相比，0.8 比例饮料的平均冲刺功率略高，总内源性 CHO 氧化率、腹部痉挛和饮料甜度是解释机制。
高果糖-麦芽糊精-葡萄糖比例（0.8）饮料可提高外源性 CHO 氧化效率，降低内源性 CHO 氧化效率，从而提高高强度耐力表现。负责的胃肠道-肝脏或其他生理部位需要进一步研究。
