Systematic Reviews
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 7, 2023; 29(17): 2679-2700
Published online May 7, 2023. doi: 10.3748/wjg.v29.i17.2679
Different types of fruit intake and colorectal cancer risk: A meta-analysis of observational studies
Zhen-Ying Wu, Jia-Li Chen, Han Li, Ke Su, Yun-Wei Han
Zhen-Ying Wu, Jia-Li Chen, Han Li, Ke Su, Yun-Wei Han, Department of Oncology, The Affiliated Hospital of Southwest Medical University, Luzhou 646099, Sichuan Province, China
Author contributions: Wu ZY and Han YW contributed to conceptualization; Wu ZY contributed to methodology; Chen JL contributed to software; Wu ZY, Chen JL, and Li H contributed to validation; Wu ZY contributed to formal analysis; Su K contributed to investigation; Su K contributed to resources; Li H contributed to data curation; Wu ZY, Chen JL, and Han YW contributed to writing-original draft preparation; all authors contributed to writing-review and editing; Chen JL contributed to visualization; Han YW contributed to supervision; Han YW contributed to project administration; all authors have read and agreed to the published version of the manuscript.
Conflict-of-interest statement: The authors declare that they have no conflict of interest.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
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: Yun-Wei Han, MD, PhD, Professor, Researcher, Department of Oncology, The Affiliated Hospital of Southwest Medical University, No. 25 Taiping Street, Jiangyang District, Luzhou 646099, Sichuan Province, China. lanpaoxiansheng@126.com
Received: December 19, 2022
Peer-review started: December 19, 2022
First decision: February 8, 2023
Revised: February 24, 2023
Accepted: March 20, 2023
Article in press: March 20, 2023
Published online: May 7, 2023
Processing time: 138 Days and 21.2 Hours
ARTICLE HIGHLIGHTS
Research background

Colorectal cancer (CRC) is the third most prevalent cancer, and the prevalence of CRC in adults aged 40-49 has increased by approximately 15% between 2000-2002 and 2014-2016. However, inconsistent findings have been reported in different studies on the association between the intake of different types of fruits and CRC. Given their different chemical compositions and underlying molecular mechanisms, some types of fruits may have a closer correlation with CRC risk than others. This meta-analysis provides more reliable evidence that a higher intake of certain fruits is more effective in CRC prevention.

Research motivation

The main topic of this study is exploring the association between intake of different types of fruits and CRC risk. The key problem to be solved is to compare the CRC risk in the highest and lowest intake groups and conduct a meta-analysis. The significance of this study is that we have found that certain types of fruits can effectively reduce CRC risk.

Research objectives

To help people improve their lifestyles and dietary habits to live a healthy life. The most important goal is to ease the CRC-related social and economic burden worldwide. In terms of goal realized, through this meta-analysis, we have found that eating more citrus, apple, watermelon and kiwi fruit can effectively reduce CRC risk. Implications of achieving the goals: Further analysis of specific types of fruit is needed to explore key anti-cancer components.

Research methods

This meta-analysis was conducted by comparing the reported CRC risk between the highest and lowest fruit intake groups. Considering that CRC is rare, the risk is less than 10%, and the OR is small, the RR/HR we have calculated is approximately equal to the OR. Heterogeneity of results across studies was assessed by the test. Publication bias was determined using funnel plots and Egger’s linear regression test. A dose-response analysis of citrus fruits was also conducted to examine a possible nonlinear relationship. All analyses were performed using R (version 4.1.3). Characteristics and novelty of the research method: No research has used this method to explore this topic before. This research direction is very suitable for this research method.

Research results

Findings: High intakes of citrus, apple, watermelon, and kiwi reduced CRC risk by 9%, 25%, 26%, and 13%, respectively, compared with low intakes. However, other types of fruit did not show an association with CRC risk. A non-linear dose-response relationship was found between citrus and CRC risk. Contribution to the field: This study performed a meta-analysis of previous data in a scientific context and identified the fruit types most effective in reducing CRC risk. Unresolved issues: More prospective studies are needed in the future to further elucidate the association between fruit and CRC.

Research conclusions

The results of this study underpin the hypothesis that certain types of fruit are effective in preventing CRC. This meta-analysis is based on the reported CRC risk of the highest and lowest fruit intake groups. It convincingly demonstrates the real association between fruit and CRC.

Research perspectives

In future research, we hope to find out the key anti-cancer components of specific types of fruits, so as to help people prevent cancer more effectively.