Total antioxidant capacity intake and colorectal cancer risk in the Health Professionals Follow-up Study

Objective: To examine the association between total antioxidant capacity (TAC) intake and colorectal cancer incidence. Methods: TAC intake was assessed in 1986 and every 4 years thereafter in the Health Professionals Follow-up Study, a prospective cohort study of 47,339 men. Between 1986 and 2004, 952 colorectal cancer cases were diagnosed. Cox proportional hazards regression models were used to estimate relative risks (RR) and 95% confidence intervals (CI). Results: Comparing the highest versus lowest quintile, TAC intake from foods only (dietary TAC) was not associated with colorectal (multivariate-RR: 0.98; 95% CI: 0.78, 1.23) or colon (multivariate-RR: 1.20; 95% CI: 0.90, 1.61) cancer risk, but was inversely associated with rectal cancer risk (multivariate-RR: 0.58; 95% CI: 0.35, 0.96). For the same comparison, TAC intake from foods and supplements (total TAC) was not associated with colorectal (multivariate-RR: 0.91; 95% CI: 0.73, 1.14), colon (multivariate-RR: 1.01; 95% CI: 0.77, 1.33), or rectal (multivariate-RR: 0.85; 95% CI: 0.52, 1.38) cancer risk. Conclusions: Dietary and total TAC intakes were not associated with colorectal and colon cancer risk. Dietary, but not total, TAC intake was inversely associated with rectal cancer risk, suggesting antioxidants per se may not be associated with rectal cancer risk.