Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200, MD, Maastricht, the Netherlands.
Department of Nutrition and Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, 6200, MD, Maastricht, the Netherlands.
Clin Nutr. 2021 Apr;40(4):1699-1710. doi: 10.1016/j.clnu.2020.09.015. Epub 2020 Sep 15.
l-arginine supplementation may improve vascular endothelial function. As tree nuts and groundnuts are a source of the amino acid l-arginine, we performed a meta-analysis of human randomized controlled trials (RCTs) to compare effects of tree nut and groundnut consumption with those of l-arginine supplementation on fasting and postprandial endothelial function as assessed by flow-mediated vasodilation of the brachial artery (FMD).
Summary estimates of weighted mean differences (WMDs) in FMD and 95% confidence intervals (CIs) were calculated using random-effect meta-analyses.
A total of thirteen RCTs focusing on tree nut and groundnut consumption and nineteen RCTs investigating effects of l-arginine supplementation were included. Longer-term consumption of tree nuts and groundnuts increased fasting FMD by 1.09 %-point (PP) (95% CI: 0.49, 1.69, P < 0.001; I: 76.7%, P < 0.001), while l-arginine supplementation (daily range: 3-21 g) increased fasting FMD by 0.53 PP (95% CI: 0.12, 0.93; P = 0.012; I: 91.6%, P < 0.001). Effects between treatments were not statistically different (P = 0.31). Tree nut and groundnut consumption did not affect postprandial FMD responses (1.25 PP, 95% CI: -0.31, 2.81, P = 0.12; I: 91.4%, P < 0.001), whereas l-arginine supplementation (range: 3-15 g) improved FMD during the postprandial phase by 2.02 PP (95% CI: 0.92, 3.13, P < 0.001; I: 99.1%, P < 0.001). However, treatment effects did not differ significantly (P = 0.60). Overall, these results derive from high-quality evidence.
Longer-term consumption of tree nuts and groundnuts, as well as l-arginine supplementation did improve fasting endothelial function, as assessed by FMD. However, the positive effects of tree nuts and groundnuts could not be fully explained by the amount of l-arginine in these nuts. Only l-arginine supplementation did improve postprandial FMD, but effects were not different from those of tree nuts and groundnuts. Future studies should focus on the identifications of the bioactive nutrients in tree nuts and groundnuts and mechanistic pathways behind differences in postprandial and longer-term fasting changes in FMD.
精氨酸补充剂可能改善血管内皮功能。由于坚果和花生是精氨酸的来源，我们进行了一项荟萃分析，比较了坚果和花生消费与精氨酸补充对肱动脉血流介导的血管舒张（FMD）评估的空腹和餐后内皮功能的影响。
使用随机效应荟萃分析计算 FMD 的加权均数差（WMD）及其 95%置信区间（CI）的汇总估计值。
共有 13 项针对坚果和花生消费的 RCT 和 19 项研究精氨酸补充影响的 RCT 被纳入。长期食用坚果和花生可使空腹 FMD 增加 1.09%（95%CI：0.49，1.69，P<0.001；I：76.7%，P<0.001），而精氨酸补充（每日剂量范围：3-21g）可使空腹 FMD 增加 0.53%（95%CI：0.12，0.93；P=0.012；I：91.6%，P<0.001）。两种治疗方法之间的效果无统计学差异（P=0.31）。坚果和花生的消费并不影响餐后 FMD 反应（1.25%，95%CI：-0.31，2.81，P=0.12；I：91.4%，P<0.001），而精氨酸补充（3-15g）可使餐后 FMD 增加 2.02%（95%CI：0.92，3.13，P<0.001；I：99.1%，P<0.001）。然而，治疗效果无显著差异（P=0.60）。总的来说，这些结果来自高质量的证据。
长期食用坚果和花生以及精氨酸补充均可改善空腹时的内皮功能，以 FMD 评估。然而，这些坚果中精氨酸的含量并不能完全解释坚果和花生的积极作用。只有精氨酸补充才能改善餐后 FMD，但效果与坚果和花生没有区别。未来的研究应集中于确定坚果和花生中的生物活性营养素以及餐后和长期空腹 FMD 变化的机制途径。
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