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
Abstract
BACKGROUND

Multiple studies investigating the relationship between intake of different types of fruit and colorectal cancer (CRC) risk have yielded inconsistent results.

AIM

To perform a meta-analysis of existing studies to assess the association between the intake of different kinds of fruit and the incidence of CRC.

METHODS

We searched online literature databases including PubMed, Embase, WOS, and Cochrane Library for relevant articles available up to August 2022. With data extracted from observational studies, odds ratios (ORs) with 95% confidence intervals (CIs) were assessed using random-effects models. A funnel plot and Egger’s test were used to determine publication bias. Furthermore, subgroup analysis and dose-response analysis were performed. All analyses were conducted using R (version 4.1.3).

RESULTS

Twenty-four eligible studies involving 1068158 participants were included in this review. The meta-analysis showed that compared to a low intake, a higher intake of citrus, apples, watermelon, and kiwi reduced the risk of CRC by 9% [OR (95%CI) = 0.91 (0.85-0.97)], 25% [OR (95%CI) = 0.75 (0.66-0.85)], 26% [OR (95%CI) = 0.74 (0.58-0.94)], 13% [OR (95%CI) = 0.87 (0.78-0.96)], respectively. No significant association was observed between the intake of other types of fruit and the risk of CRC. In the dose-response analysis, a nonlinear association was found [R (95%CI) = -0.0031 (-0.0047 to -0.0014)] between citrus intake and CRC risk (P < 0.001), with the risk minimized around 120 g/d (OR = 0.85), while no significant dose-response correlation was observed after continued increase in intake.

CONCLUSION

We found that a higher intake of citrus, apples, watermelon, and kiwi was negatively associated with the risk of CRC, while the intake of other types of fruits were not significantly associated with CRC. Citrus intake showed a non-linear dose-response relationship with the risk of CRC. This meta-analysis provides further evidence that a higher intake of specific types of fruit is effective in preventing the occurrence of CRC.

Keywords: Colorectal cancer; Fruit; Dose; Systematic review; Meta-analysis

Core Tip: In this study, we summarized and analyzed existing studies on the association between the intake of different types of fruit and the risk of colorectal cancer (CRC). Some specific types of fruit, such as citrus and apples, were found to reduce the incidence of CRC. We also found a nonlinear association between citrus intake and CRC risk in the dose-response analysis. Finally, this study proposed that people should change their diets to lower the risk of CRC, thereby easing the heavy economic burden of cancer worldwide.