The effect of grape products on liver enzymes: A systematic review and meta‐analysis of randomized controlled trials

Mohammad Zamani, Damoon Ashtary‐Larky, Nadia Hafizi, Fatemeh Naeini, Mahnaz Rezaei Kelishadi, Cain C. T. Clark, Sayed Hosein Davoodi, Omid Asbaghi

    Research output: Contribution to journalReview articlepeer-review

    2 Citations (Scopus)


    The favorable influence of grape consumption on metabolic diseases has previously been shown in studies. We sought to assess the effects of grape intake on liver enzymes, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP), in adults. We performed literature search in online databases, to find eligible randomized controlled trials (RCTs). we considered RCTs that met the following criteria: RCTs consisted of use of grape products on ALT, AST, and ALP in adults (≥18 years) with at least 2 weeks intervention duration. Pooling data from 11 trials showed that grape products intake significantly reduced ALP (p = .010), without any significant changes in ALT (p = .234) and AST (p = .300). In subgroup analysis, we found a significant reduction in ALP, ALT, and AST when the duration of intervention was ≥12 weeks, and when grape seed extract (GSE) was administered. The variable duration and dosage of intervention was one of the sources of bias in our meta-analysis. Additionally, participants involved in included studies had different physiological status and various age groups. Grape products administration may significantly improve ALT, AST, and ALP in adults in long-term interventions and/or when GSE is administered. It should be noted that the favorable effects of grape consumption were small and may not reach clinical importance.
    Original languageEnglish
    Pages (from-to)4491-4503
    Number of pages13
    JournalPhytotherapy Research
    Issue number12
    Early online date20 Oct 2022
    Publication statusPublished - Dec 2022

    Bibliographical note

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    © 2022 John Wiley & Sons Ltd.


    • grape
    • liver
    • meta-analysis
    • systematic review


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