Effect of nut consumption on vascular endothelial function: A systematic review and meta-analysis of randomized controlled trials

  • Yunjun Xiao
    Correspondence
    Corresponding author. Department of Nutrition and Food Hygiene, Shenzhen Center for Disease Control and Prevention, Longyuan Road No 8, Nanshan District, Shenzhen, China. Fax: +86 755 2561 7321.
    Affiliations
    Department of Nutrition and Food Hygiene, Shenzhen Center for Disease Control and Prevention, Shenzhen, China
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  • Wei Huang
    Affiliations
    Department of Nutrition and Food Hygiene, Shenzhen Center for Disease Control and Prevention, Shenzhen, China
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  • Chaoqiong Peng
    Affiliations
    Department of Nutrition and Food Hygiene, Shenzhen Center for Disease Control and Prevention, Shenzhen, China
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  • Jinzhou Zhang
    Affiliations
    Department of Nutrition and Food Hygiene, Shenzhen Center for Disease Control and Prevention, Shenzhen, China
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  • Carmen Wong
    Affiliations
    School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
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  • Jean H. Kim
    Affiliations
    School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
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  • Eng-kiong Yeoh
    Affiliations
    School of Public Health and Primary Care, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
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  • Xuefen Su
    Correspondence
    Corresponding author. School of Public Health and Primary Care, Faculty of Medicine, Room 508, School of Public Health, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China. Fax: +852 2645 3098.
    Affiliations
    School 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
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Published:April 20, 2017DOI:https://doi.org/10.1016/j.clnu.2017.04.011

      Summary

      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.

      Keywords

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