Unveiling the Effects of Cruciferous Vegetable Intake on Different Cancers: A Systematic Review and Dose-Response Meta-analysis.

Context: Epidemiological studies indicated that cruciferous vegetable intake is associated with positive health outcomes. However, the role of cruciferous vegetables may have differential impacts on various cancers.

Objective: This meta-analysis aims to review recent epidemiological studies on the link between cruciferous vegetables and various cancers. It seeks to identify the optimal intake dose and timing of cruciferous vegetables influencing their association with cancer risk.

Data sources: Studies on cruciferous vegetables and cancer were searched in PubMed, NCBI, Web of Science, and Elsevier databases from 1978 to June 2023.

Data extraction: Extracted data from 226 relevant case-control and cohort studies were expressed by standardized mean difference and 95% CI, followed by the subgroup analysis to eliminate heterogeneity.

Results: Intake of cruciferous vegetables can prevent cancers, with an odds ratio of 0.77 and risk ratio (RR) of 0.96. The intake levels of cruciferous vegetables associated with the risk of colorectal cancer, lung cancer, upper gastrointestinal cancer, gynecological cancer (ovarian cancer and endometrial cancer), bladder cancer, renal cancer, and prostate cancer were found to be 5.41 servings/week, 5.41 servings/week, 5.5 servings/week, 7.4 servings/week, 5.5 servings/week, 4.85 servings/week, and 3 servings/week, respectively. In a cohort followed for 2 to 15 years, limited consumption of cruciferous vegetables was correlated with a higher cancer RR. In the Asian population, cruciferous vegetables had a significant relationship with lung cancer, head and neck squamous cell carcinoma, and esophageal cancer. Conversely, cruciferous vegetables are predominantly associated with colorectal, renal, gynecological, and prostate cancer in the American population.

Conclusion: This study highlights the complex link between cruciferous vegetables and cancer, influenced by factors such as cancer type, region, intake level, and follow-up duration.