Coggan Andrew R, Leibowitz Joshua L, Kadkhodayan Ana, Thomas Deepak P, Ramamurthy Sujata, Spearie Catherine Anderson, Waller Suzanne, Farmer Marsha, Peterson Linda R
Cardiovascular Imaging Laboratory, Division of Radiological Sciences, Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Cardiovascular Imaging Laboratory, Division of Radiological Sciences, Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
Nitric Oxide. 2015 Aug 1;48:16-21. doi: 10.1016/j.niox.2014.08.014. Epub 2014 Sep 6.
Nitric oxide (NO) has been demonstrated to enhance the maximal shortening velocity and maximal power of rodent muscle. Dietary nitrate (NO3(-)) intake has been demonstrated to increase NO bioavailability in humans. We therefore hypothesized that acute dietary NO3(-) intake (in the form of a concentrated beetroot juice (BRJ) supplement) would improve muscle speed and power in humans. To test this hypothesis, healthy men and women (n = 12; age = 22-50 y) were studied using a randomized, double-blind, placebo-controlled crossover design. After an overnight fast, subjects ingested 140 mL of BRJ either containing or devoid of 11.2 mmol of NO3(-). After 2 h, knee extensor contractile function was assessed using a Biodex 4 isokinetic dynamometer. Breath NO levels were also measured periodically using a Niox Mino analyzer as a biomarker of whole-body NO production. No significant changes in breath NO were observed in the placebo trial, whereas breath NO rose by 61% (P < 0.001; effect size = 1.19) after dietary NO3(-) intake. This was accompanied by a 4% (P < 0.01; effect size = 0.74) increase in peak knee extensor power at the highest angular velocity tested (i.e., 6.28 rad/s). Calculated maximal knee extensor power was therefore greater (i.e., 7.90 ± 0.59 vs. 7.44 ± 0.53 W/kg; P < 0.05; effect size = 0.63) after dietary NO3(-) intake, as was the calculated maximal velocity (i.e., 14.5 ± 0.9 vs. 13.1 ± 0.8 rad/s; P < 0.05; effect size = 0.67). No differences in muscle function were observed during 50 consecutive knee extensions performed at 3.14 rad/s. We conclude that acute dietary NO3(-) intake increases whole-body NO production and muscle speed and power in healthy men and women.
一氧化氮（NO）已被证明可提高啮齿动物肌肉的最大缩短速度和最大功率。膳食硝酸盐（NO3(-)）的摄入已被证明可提高人体中NO的生物利用度。因此，我们假设急性膳食NO3(-)摄入（以浓缩甜菜根汁（BRJ）补充剂的形式）会改善人体肌肉速度和力量。为了验证这一假设，我们采用随机、双盲、安慰剂对照交叉设计对健康男性和女性（n = 12；年龄 = 22 - 50岁）进行了研究。在禁食过夜后，受试者摄入140 mL含有或不含11.2 mmol NO3(-)的BRJ。2小时后，使用Biodex 4等速测力计评估膝伸肌收缩功能。还定期使用Niox Mino分析仪测量呼出NO水平，作为全身NO产生的生物标志物。在安慰剂试验中未观察到呼出NO有显著变化，而在摄入膳食NO3(-)后，呼出NO增加了61%（P < 0.001；效应大小 = 1.19）。这伴随着在测试的最高角速度（即6.28 rad/s）下膝伸肌峰值功率增加了4%（P < 0.01；效应大小 = 0.74）。因此，摄入膳食NO3(-)后计算得出的最大膝伸肌功率更大（即7.90 ± 0.59 vs. 7.44 ± 0.53 W/kg；P < 0.05；效应大小 = 0.63），计算得出的最大速度也是如此（即14.5 ± 0.9 vs. 13.1 ± 0.8 rad/s；P < 0.05；效应大小 = 0.67）。在以3.14 rad/s进行50次连续膝伸展过程中，未观察到肌肉功能有差异。我们得出结论，急性膳食NO3(-)摄入可增加健康男性和女性的全身NO产生以及肌肉速度和力量。
