Phytochemically rich dietary components and the risk of colorectal cancer: A systematic review and meta-analysis of observational studies

Abstract

BACKGROUND Personalized nutrition and protective diets and lifestyles represent a key cancer research priority. The association between consumption of specific dietary components and colorectal cancer (CRC) incidence has been evaluated by a number of population-based studies, which have identified certain food items as having protective potential, though the findings have been inconsistent. Herein we present a systematic review and meta-analysis on the potential protective role of five common phytochemically rich dietary components (nuts, cruciferous vegetables, citrus fruits, garlic and tomatoes) in reducing CRC risk. AIM To investigate the independent impact of increased intake of specific dietary constituents on CRC risk in the general population. METHODS Medline and Embase were systematically searched, from time of database inception to January 31, 2020, for observational studies reporting CRC incidence relative to intake of one or more of nuts, cruciferous vegetables, citrus fruits, garlic and/or tomatoes in the general population. Data were extracted by two independent reviewers and analyzed in accordance with the Meta-analysis of Observational Studies in Epidemiology (MOOSE) and Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) reporting guidelines and according to predefined inclusion/exclusion criteria. Effect sizes of studies were pooled using a random-effects model. RESULTS Forty-six studies were identified. CRC risk was significantly reduced in patients with higher vs lower consumption of cruciferous vegetables [odds ratio (OR) = 0.90; 95% confidence interval (CI): 0.85-0.95; P < 0.005], citrus fruits (OR = 0.90; 95%CI: 0.84-0.96; P < 0.005), garlic (OR = 0.83; 95%CI: 0.76-0.91; P < 0.005) and tomatoes (OR = 0.89; 95%CI: 0.84-0.95; P < 0.005). Subgroup analysis showed that this association sustained when looking at case-control studies alone, for all of these four food items, but no significant difference was found in analysis of cohort studies alone. Nut consumption exhibited a similar trend, but overall results were not significant (OR = 0.72; 95%CI: 0.50-1.03; P < 0.07; I 2 = 90.70%). Putative anticarcinogenic mechanisms are proposed using gene-set enrichment analysis of gene/protein perturbations caused by active compounds within each food item. CONCLUSION Increased cruciferous vegetable, garlic, citrus fruit and tomato consumption are all inversely associated with CRC risk. These findings highlight the potential for developing precision nutrition strategies for CRC prevention.

Nut consumption and urogenital and genital, gastrointestinal and women‐related cancers: Assessment and review

“…125 Recently, another meta-analysis of observational studies on the effects of phytochemically rich diets and CRC risk has confirmed the finding of Wu et al Borgas and co-workers reported a significant association between higher consumption of dietary nuts and decreased risk of CRC. 126 However, they observed a significant heterogeneity that made it difficult to achieve a reliable conclusion based on currently available data.…”

Garlic consumption and colorectal cancer risk in US adults: a large prospective cohort study

“…It is notable that although previous studies have demonstrated a generally inverse association of garlic consumption with allcause mortality (9) and various cancer sites (10)(11)(12)(13)(14)(15), including colorectal cancer, these findings are inconsistent. While the recent meta-analysis (4,5,(16)(17)(18)(19) and case-controlled studies (20)(21)(22) support this inverse association, some meta-analysis (23)(24)(25) and prospective cohorts (26,27) showed no such association.…”

The advantages, disadvantages, threats, and opportunities of electronic patient-reported outcome systems in cancer: A systematic review

“… 1 Beyond physical symptoms, cancer profoundly impacts patients’ psychological well-being and quality of life, necessitating effective reporting of the patient’s condition and the application of management strategies for treatment. 2 , 3 Traditional paper-based reporting approaches encounter limitations in real-time data collection, integrity, and accessibility, prompting a transition to electronic reporting systems. The burden on cancer patients to report outcomes consistently and regularly through traditional methods is especially high, and failing to collect that data could hurt the completeness of studies essential for regulatory approval.…”