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©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
Dietary phytochemical consumption is inversely associated with liver alkaline phosphatase in Middle Eastern adults
Zahra Darabi, Richard James Webb, Hassan Mozaffari-Khosravi, Masoud Mirzaei, Ian Glynn Davies, Sayyed Saeid Khayyatzadeh, Mohsen Mazidi
Zahra Darabi, Sayyed Saeid Khayyatzadeh, Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Zahra Darabi, Hassan Mozaffari-Khosravi, Sayyed Saeid Khayyatzadeh, Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Richard James Webb, School of Health Sciences, Liverpool Hope University, Liverpool L16 9JD, United Kingdom
Hassan Mozaffari-Khosravi, Nutrition and Food Security Research Center, Shahid Sadoghi University of Medical Sciences, Yazd, Iran
Masoud Mirzaei, Yazd Cardiovascular Research Centre, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
Ian Glynn Davies, School of Sports and Exercise Sciences, Faculty of Science, Liverpool John Moores University, IM Marsh Campus, Barkhill Road, Liverpool L17 6AF, United Kingdom
Mohsen Mazidi, Medical Research Council Population Health Research Unit, Nuffield Department of Population Health, University of Oxford, Oxford OX3 7LF, United Kingdom
Mohsen Mazidi, Department of Twin Research & Genetic Epidemiology, King’s college London, South Wing St Thomas', London SE1 7EH, United Kingdom
Author contributions: Darabi Z, Mozaffari-Khosravi H, Mirzaei M, Khayyatzadeh SS, and Mazidi M conceived and designed the study, acquired and analysed the data; Darabi Z and Webb RJ interpreted the data and wrote the first draft of the manuscript; All authors critically revised the manuscript.
Institutional review board statement: The study was also approved by the ethics committee of Shahid Sadoughi University of Medical Sciences (approval code: IR.SSU.SPH.REC.1397.161).
Informed consent statement: All involved persons gave their informed consent prior to study inclusion.
Conflict-of-interest statement: The authors know of no conflicts of interest associated with this publication, and there has been no significant financial support for this work that could have influenced its outcome.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at mohsen.mazidi@ndph.ox.ac.uk.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
https://creativecommons.org/Licenses/by-nc/4.0/ Corresponding author: Mohsen Mazidi, PhD, Research Scientist, Medical Research Council Population Health Research Unit, Nuffield Department of Population Health, University of Oxford, Richard Doll Building, Old Road Campus, Headington, Oxford OX3 7LF, United Kingdom. mohsen.mazidi@ndph.ox.ac.uk
Received: November 6, 2021
Peer-review started: November 6, 2021
First decision: December 27, 2021
Revised: January 28, 2022
Accepted: May 7, 2022
Article in press: May 7, 2022
Published online: May 27, 2022
Processing time: 199 Days and 4.2 Hours
BACKGROUND
The hepatoprotective effects of phytochemicals are controversial. A dietary phytochemical index (DPI) has been suggested as an alternative method for quantifying the phytochemical content of foods.
AIM
To assess the DPI in relation to liver function tests among a representative sample of Iranian adults.
METHODS
A total of 5111 participants aged 35-70 years old were included in this cross-sectional study by a multistage cluster random sampling method. Dietary intakes were collected by a validated and reliable food frequency questionnaire with 121 items. DPI was calculated by the percent of daily energy intake taken from phytochemical-rich foods. Fasting serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and gamma glutamyl transferase (GGT) were determined. Linear regression was used to investigate the association between DPI and levels of liver enzymes using crude and adjusted models.
RESULTS
There was an inverse association between DPI score and serum ALP in the crude model (β = -0.05; P < 0.001). This association remained significant after adjustment for body mass index, age, smoking, energy intake, history of diabetes, and education (β = -0.03; P = 0.01). No significant associations were found between DPI score and serum levels of AST, ALT, and GGT. The individuals with the highest DPI scores consumed significantly higher amounts of fruits, vegetables, legumes, nuts, and cereals, yet were shown to have significantly higher serum total cholesterol and low-density lipoprotein cholesterol, as well as several other metabolic abnormalities.
CONCLUSION
Higher adherence to phytochemical-rich foods was associated with lower levels of ALP, but no change in other liver enzymes. Those with higher DPI scores also consumed food items associated with a healthier overall dietary pattern; however, they also presented several unexpected metabolic derangements. Additional randomised trials are needed to better determine the effects of phytochemical-rich foods on liver function.
Core Tip: It has been debated whether phytochemicals are hepatoprotective. Furthermore, to the authors knowledge, this has not previously been researched in an Iranian population. In our study we used a dietary phytochemical index to categorise participants in terms of their intake of dietary phytochemicals. We found that participants with higher intakes of phytochemicals had a healthier overall dietary pattern and lower levels of alanine aminotransferase, which may be suggestive of improved liver function. Despite this, several metabolic disturbances were also revealed in these participants.
