Intake of polyphenols from cereal foods and colorectal cancer risk in the Melbourne Collaborative Cohort Study

• Published in: Cancer medicine (Malden, MA) MA), 2023-09, Vol.12 (18), p.19188-19202
• Main Authors: Vingrys, Kristina, Mathai, Michael L., McAinch, Andrew J., Bassett, Julie K., Courten, Maximilian, Stojanovska, Lily, Millar, Lynne, Giles, Graham G., Hodge, Allison M., Apostolopoulos, Vasso
• Format: Article
• Language: English
• Subjects: Breakfast foods; Cell growth; Cereals; Cohort analysis; Collaboration; Colorectal cancer; Colorectal carcinoma; Diet; Energy intake; Flavonoids; Food; food frequency questionnaire; Grain; Melbourne Collaborative Cohort Study; Metabolites; Phenolic acids; Physical activity; Polyphenols; Questionnaires; Rice; Self report; Survival analysis
• ISSN: 2045-7634; 2045-7634
• DOI: 10.1002/cam4.6514

Background Cereal‐derived polyphenols have demonstrated protective mechanisms in colorectal cancer (CRC) models; however, confirmation in human studies is lacking. Therefore, this study examined the association between cereal polyphenol intakes and CRC risk in the Melbourne Collaborative Cohort Study (MCCS), a prospective cohort study in Melbourne, Australia that recruited participants between 1990 and 1994 to investigate diet–disease relationships. Methods Using food frequency questionnaire diet data matched to polyphenol data, dietary intakes of alkylresorcinols, phenolic acids, lignans, and total polyphenols from cereals were estimated. Hazard ratios (HRs) and 95% confidence intervals for CRC risk were estimated for quintiles of intake with the lowest quintile as the comparison category, using multivariable adjusted Cox proportional hazards models with age as the time axis adjusted for sex, socio‐economic status, alcohol consumption, fibre intake, country of birth, total energy intake, physical activity and smoking status. Results From 35,245 eligible adults, mean (SD) age 54.7 (8.6) years, mostly female (61%) and Australian‐born (69%), there were 1394 incident cases of CRC (946 colon cancers and 448 rectal cancers). Results for total cereal polyphenol intake showed reduced HRs in Q2 (HR: 0.80; 95% CI, 0.68–0.95) and Q4 (HR: 0.75; 95% CI, 0.62–0.90), and similar for phenolic acids. Alkylresorcinol intake showed reduced HR in Q3 (HR: 0.80; 95% CI, 0.67–0.95) and Q4 (HR: 0.79; 95% CI, 0.66–0.95). Conclusions Overall, the present study showed little evidence of association between intakes of cereal polyphenols and CRC risk. Future investigations may be useful to understand associations between cereal‐derived polyphenols and additional cancers in different populations. Grains and cereals may offer chemoprotection in colorectal cancer (CRC), that may partly be attributed to polyphenols from cereal foods; however, populations studies are lacking. Utilising a cereal‐specific polyphenol database designed for a specific Australian cohort, survival analysis revealed limited association between cereal polyphenol intake and CRC risk. While the study findings are in general agreement with cohort studies from total foods, further comparative studies are needed.