Department of Nutrition and Dietetics, Saint Louis University, 3437 Caroline Street, St Louis, MO 63104, USA.
J Acad Nutr Diet. 2012 Apr;112(4):548-52. doi: 10.1016/j.jand.2011.12.002.
Nitrate ingestion improves exercise performance; however, it has also been linked to adverse health effects, except when consumed in the form of vegetables. The purpose of this study was to determine, in a double-blind crossover study, whether whole beetroot consumption, as a means for increasing nitrate intake, improves endurance exercise performance. Eleven recreationally fit men and women were studied in a double-blind placebo controlled crossover trial performed in 2010. Participants underwent two 5-km treadmill time trials in random sequence, once 75 minutes after consuming baked beetroot (200 g with ≥500 mg nitrate) and once 75 minutes after consuming cranberry relish as a eucaloric placebo. Based on paired t tests, mean running velocity during the 5-km run tended to be faster after beetroot consumption (12.3±2.7 vs 11.9±2.6 km/hour; P=0.06). During the last 1.1 miles (1.8 km) of the 5-km run, running velocity was 5% faster (12.7±3.0 vs 12.1±2.8 km/hour; P=0.02) in the beetroot trial, with no differences in velocity (P≥0.25) in the earlier portions of the 5-km run. No differences in exercise heart rate were observed between trials; however, at 1.8 km into the 5-km run, rating of perceived exertion was lower with beetroot (13.0±2.1 vs 13.7±1.9; P=0.04). Consumption of nitrate-rich, whole beetroot improves running performance in healthy adults. Because whole vegetables have been shown to have health benefits, whereas nitrates from other sources may have detrimental health effects, it would be prudent for individuals seeking performance benefits to obtain nitrates from whole vegetables, such as beetroot.
硝酸盐摄入可提高运动表现；然而，除了以蔬菜形式摄入外，它也与不良健康影响有关。本研究旨在通过双盲交叉研究确定，食用完整甜菜根（含≥500mg 硝酸盐的 200g）是否可以增加硝酸盐摄入，从而提高耐力运动表现。2010 年，11 名有规律运动的健康男性和女性参与了这项双盲安慰剂对照交叉试验。参与者在双盲条件下随机进行了两次 5 公里跑步机时间试验，一次是在食用烤甜菜根（200g，含≥500mg 硝酸盐）后 75 分钟，一次是在食用蔓越莓酱（热量相同的安慰剂）后 75 分钟。根据配对 t 检验，食用甜菜根后 5 公里跑的平均跑步速度略有加快（12.3±2.7 比 11.9±2.6 公里/小时；P=0.06）。在 5 公里跑的最后 1.1 英里（1.8 公里），食用甜菜根组的跑步速度快 5%（12.7±3.0 比 12.1±2.8 公里/小时；P=0.02），而 5 公里跑的前半段速度没有差异（P≥0.25）。两次试验中运动时的心率没有差异；然而，在 5 公里跑的 1.8 公里处，食用甜菜根时的感觉用力程度较低（13.0±2.1 比 13.7±1.9；P=0.04）。食用富含硝酸盐的完整甜菜根可提高健康成年人的跑步表现。由于完整蔬菜已被证明具有健康益处，而来自其他来源的硝酸盐可能对健康有害，因此，寻求提高运动表现的个体应明智地从甜菜根等完整蔬菜中获取硝酸盐。
