Clin Nutr. 2017 Apr 20. pii: S0261-5614(17)30150-4. doi: 10.1016/j.clnu.2017.04.011. [Epub ahead of print] Effect of nut consumption on vascular endothelial function: A systematic review and meta-analysis of randomized controlled trials. Xiao Y1, Huang W2, Peng C2, Zhang J2, Wong C3, Kim JH3, Yeoh EK3, Su X4. Author information 1Department of Nutrition and Food Hygiene, Shenzhen Center for Disease Control and Prevention, Shenzhen, China. Electronic address: firstname.lastname@example.orgDepartment of Nutrition and Food Hygiene, Shenzhen Center for Disease Control and Prevention, Shenzhen, China.3School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.4School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China; The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, China. Electronic address: email@example.com.
OBJECTIVE: Nut consumption has consistently been found to be associated with a reduced risk of cardiovascular diseases (CVD) and mortality in prospective studies. However, its effect on endothelial function, a prognostic marker of CVD, is still controversial in clinical trials. This meta-analysis of randomized controlled trials (RCTs) aimed to quantitatively assess the effect of nuts on vascular endothelial function.
METHODS: Major electronic databases were searched for published RCTs that reported the effect of nuts on flow mediated dilation (FMD) as a measurement of endothelial function in the adult population (age eighteen years or over). We calculated the pooled estimates of weighted mean differences (WMDs) and their 95% confidence intervals (CIs) by using random-effects models.
RESULTS: A total of nine papers (10 trials) involving 374 participants were included. The pooled estimates found that nut consumption significantly improved FMD (WMD: 0.41%; 95% CI: 0.18%, 0.63%; P = 0.001). Moderate and marginally significant heterogeneity was observed among the studies (I2 = 39.5%, P = 0.094). Subgroup analyses indicated that walnuts significantly improved FMD (WMD: 0.39%; 95% CI: 0.16%, 0.63%; P = 0.001). In addition, nut consumption had a significant effect on FMD in the trials with study duration <18 weeks, nut dose <67 g/d, or subjects with baseline FMD ≥8.6%.
CONCLUSIONS: Nut consumption significantly improved endothelial function. However, the beneficial effect was limited to walnuts. More studies examining the effect of other nuts on endothelial function are needed in the future. Copyright © 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved. Endothelial Function Scientific Update Sponsored by Endothelix Inc. www.endothelix.com