Discipline of Nutrition, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
Sports Med. 2017 Aug;47(8):1619-1636. doi: 10.1007/s40279-017-0677-3.
N-Acetylcysteine (NAC) is a promising antioxidant supplement with potential as an acute strategy to enhance performance in elite sport, but there are concerns about its side effects with high doses.
To review the current literature and evaluate the effects of NAC supplementation on sport performance and the risk of adverse effects.
The literature up to May 2016 was searched on MEDLINE (PubMed), EMBASE, SPORTDiscus, Google Scholar and Scopus databases to identify all studies investigating the effects of NAC supplementation on exercise performance and/or side effects experienced. Performance outcomes from each study were converted to the percent effect equivalent to mean power output in a time trial. All pooled analyses were based on random-effects models generated by Review Manager (RevMan) [Computer program], version 5.3 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, 2014).
A total of seven studies met criteria for inclusion in the sport performance meta-analysis, and 17 for inclusion in the side effects meta-analysis. The typical daily dose of NAC reported was 5.8 g·d; with a range between 1.2 and 20.0 g·d. The mean increase in performance was 0.29% (95% confidence interval -0.67 to 1.25). The difference in the odds ratio of side effects on NAC compared with placebo was 1.11 (95% confidence interval 0.88-1.39). The sub-analysis of NAC dose suggested an increase in side effects as the dosage of NAC increased; however, this observation requires further investigation.
Despite initial research publications reporting positive performance effects with NAC, at this stage it cannot be recommended further. The risk of side effects from NAC supplementation also remains unclear owing to significant variations in effects. Suboptimal reporting and documentation in the literature creates difficulties when meta-analysing outcomes and generating conclusions.
N-乙酰半胱氨酸（NAC）是一种很有前途的抗氧化补充剂，有可能成为提高精英运动表现的急性策略，但高剂量时存在副作用的担忧。
综述当前文献，评估 NAC 补充对运动表现和不良反应风险的影响。
截至 2016 年 5 月，在 MEDLINE（PubMed）、EMBASE、SPORTDiscus、Google Scholar 和 Scopus 数据库中检索了所有研究 NAC 补充对运动表现和/或不良反应影响的文献。每项研究的运动表现结果均转换为与计时赛平均功率输出等效的百分效应。所有汇总分析均基于 Review Manager（RevMan）[计算机程序]生成的随机效应模型，版本 5.3（北欧 Cochrane 中心，Cochrane 协作组织，哥本哈根，2014 年）。
共有 7 项研究符合运动表现荟萃分析纳入标准，17 项研究符合不良反应荟萃分析纳入标准。报告的 NAC 典型日剂量为 5.8 g·d；范围为 1.2 至 20.0 g·d。性能提高的平均幅度为 0.29%（95%置信区间-0.67 至 1.25）。与安慰剂相比，NAC 不良反应的优势比差异为 1.11（95%置信区间 0.88-1.39）。NAC 剂量的亚分析表明，随着 NAC 剂量的增加，不良反应的风险增加；然而，这一观察结果需要进一步研究。
尽管最初的研究报告显示 NAC 具有积极的运动效果，但在现阶段，不能推荐进一步使用。由于不良反应的影响存在显著差异，因此 NAC 补充的不良反应风险仍不清楚。文献中报告和记录的不充分使得对结果进行荟萃分析和得出结论变得困难。
