Dietary Fat and Fatty Acids Intake in Relation to Risk of Colorectal Cancer

Abstract

Abstract Objectives Epidemiologic evidence for specific types and sources of dietary fat and individual fatty acid with colorectal cancer (CRC) risk remains inconclusive. We aimed to comprehensively examine the associations of intake of specific types (saturated-, monounsaturated-, polyunsaturated-, and trans-) and sources (animal-, dairy-, and vegetable-) of dietary fat and fatty acids with CRC risk. Methods We prospectively followed-up 65,550 women from the Nurses’ Health Study (1986–2014) and 45,684 men from the Health Professionals Follow-up Study (1986–2014). Dietary intake was assessed every 4 years using food frequency questionnaires. Self-reported CRC cases were confirmed through medical record review. Time-dependent Cox proportional hazards regression was used to estimate the HR for intakes of dietary fat and fatty acids and CRC risk. Results During 2,705,560 person-years of follow-up, 2726 incident CRC cases were confirmed. Intake of monounsaturated fatty acid (MUFA) tended to be positively associated with the risk of CRC (HR comparing extreme quintiles 1.21; 95% CI 1.00, 1.47; P = 0.06 for trend) compared with total carbohydrates. This positive association was mainly driven by MUFA from animal sources (MUFA-As) (HR 1.25; 95% CI 1.02, 1.53; P = 0.02 for trend). The positive association between MUFA-As and CRC was attenuated after adjusting for red and processed meat consumption (HR 1.17; 95% CI 0.94, 1.46). Other types and sources of fat intake and individual fatty acid intake were not associated with CRC risk. Isocalorically replacing MUFA-As with equivalent energy (5%) from carbohydrates from whole grains was associated with a trend towards a lower risk of CRC (HR 0.88; 95% CI 0.77, 1.01). Conclusions Higher intake of MUFA-As was associated with higher CRC risk compared with total carbohydrates or carbohydrates from whole grains, possibly due to other components of animal-sourced foods. We did not find clear associations between other types and sources of dietary fat and CRC risk. Funding Sources National Institutes of Health (UM1 CA186107, P01 CA87969, and U01 CA167552)