Dietary Fiber Intake Modifies the Positive Association between n–3 PUFA Intake and Colorectal Cancer Risk in a Caucasian Population1–3

Abstract

Background: The association between dietary fat intake and the risk of colorectal cancer (CRC) is still unclear.Objectives: We analyzed whether intakes of dietary polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs) were associated with CRC risk and whether these associations were modified by dietary fiber (DF) intake.Methods: This study was embedded in the Rotterdam Study, a prospective cohort study among subjects aged ≥55 y (n = 4967). At baseline, diet was measured by a food-frequency questionnaire. CRC events were diagnosed on the basis of pathology data and medical records. Multivariable adjusted HRs were calculated using Cox regression models.Results: During a mean follow-up period of 14.6 y, we identified 222 incident cases of CRC. There was no association between total PUFA, n–6 (ω-6) PUFA, or SFA intake and CRC risk. n–3 PUFA intake was associated with an increased risk of CRC [tertile 3 vs. tertile 1: HR = 1.44 (95% CI: 1.02, 2.04), P-trend = 0.04]. When data were analyzed by food sources, only n–3 PUFAs from nonmarine sources were associated with an increased risk of CRC. A significant interaction between n–3 PUFA and DF intakes was found (P-interaction = 0.02). After stratification by median DF intake, an increased risk of CRC caused by n–3 PUFA intake was observed in participants with a DF intake less than the median [tertile 3 vs. tertile 1: HR = 1.96 (95% CI: 1.20, 3.19), P-trend = 0.01]. No association was observed in subjects with DF intake equal to or higher than the median.Conclusions: This study suggests that intake of n–3 PUFAs by adults is associated with an increased risk of CRC, which may be driven mainly by sources other than fish. Moreover, a complex interaction with DF intake may be present.