title: The Interaction between Dietary Fiber and Fat and Risk of Colorectal Cancer in the Women's Health Initiative.
abstract: Combined intakes of specific dietary fiber and fat subtypes protect against colon cancer in animal models. We evaluated associations between self-reported individual and combinations of fiber (insoluble, soluble, and pectins, specifically) and fat (omega-6, omega-3, and docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), specifically) and colorectal cancer (CRC) risk in the Women's Health Initiative prospective cohort (n= 134,017). During a mean 11.7 years (1993-2010), 1952 incident CRC cases were identified. Cox regression models computed multivariate adjusted hazard ratios to estimate the association between dietary factors and CRC risk. Assessing fiber and fat individually, there was a modest trend for lower CRC risk with increasing intakes of total and insoluble fiber (p-trend0.09 and 0.08). An interaction (p= 0.01) was observed between soluble fiber and DHA + EPA, with protective effects of DHA + EPA with lower intakes of soluble fiber and an attenuation at higher intakes, however this association was no longer significant after correction for multiple testing. These results suggest a modest protective effect of higher fiber intake on CRC risk, but not in combination with dietary fat subtypes. Given the robust results in preclinical models and mixed results in observational studies, controlled dietary interventions with standardized intakes are needed to better understand the interaction of specific fat and fiber subtypes on colon biology and ultimately CRC susceptibility in humans.
authors.affiliation: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. snavarro@fredhutch.org.
authors.forename: Sandi L
authors.initials: SL
authors.lastname: Navarro
authors.affiliation: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. mneuhous@fredhutch.org.|Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA 98105, USA. mneuhous@fredhutch.org.
authors.forename: Marian L
authors.initials: ML
authors.lastname: Neuhouser
authors.affiliation: Division of Cancer Prevention and Population Sciences, Roswell Park Cancer Institute, Buffalo, NY 14263, USA. david.cheng@roswellpark.org.
authors.forename: Ting-Yuan David
authors.initials: TD
authors.lastname: Cheng
authors.affiliation: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. ltinker@whi.org.
authors.forename: Lesley F
authors.initials: LF
authors.lastname: Tinker
authors.affiliation: Division of Preventive Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA. jshikany@uabmc.edu.
authors.forename: James M
authors.initials: JM
authors.lastname: Shikany
authors.affiliation: Department of Epidemiology, University of Iowa, Iowa City, IA 52242, USA. linda-snetselaar@uiowa.edu.
authors.forename: Linda
authors.initials: L
authors.lastname: Snetselaar
authors.affiliation: Department of Nutritional Sciences, University of Arizona Cancer Center, Tucson, AZ 85724, USA. jam1@email.arizona.edu.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Martinez
authors.affiliation: Department of Oncology and Pathology, Wayne State University, Detroit, MI 48201, USA. katoi@karmanos.org.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Kato
authors.affiliation: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. beresfrd@uw.edu.|Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA 98105, USA. beresfrd@uw.edu.
authors.forename: Shirley A A
authors.initials: SA
authors.lastname: Beresford
authors.affiliation: Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, TX 77843, USA. r-chapkin@tamu.edu.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Chapkin
authors.affiliation: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. jlampe@fredhutch.org.|Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA 98105, USA. jlampe@fredhutch.org.
authors.forename: Johanna W
authors.initials: JW
authors.lastname: Lampe
mesh_terms: D000368:Aged; D015179:Colorectal Neoplasms / Q000517:prevention & control*; D004034:Diet Surveys; D004041:Dietary Fats / Q000008:administration & dosage*; D004043:Dietary Fiber / Q000008:administration & dosage*; D005260:Female; D006291:Health Policy; D006801:Humans; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D004041:Dietary Fats; D004043:Dietary Fiber
keywords: DHA; EPA; butyrate; colorectal cancer; fat; fiber; omega-3; pectin