title: Micronutrient intake and risk of colon and rectal cancer in a Danish cohort.
abstract: BACKGROUND
  Micronutrients may protect against colorectal cancer. Especially folate has been considered potentially preventive. However, studies on folate and colorectal cancer have found contradicting results; dietary folate seems preventive, whereas folic acid in supplements and fortification may increase the risk.
  
  
  OBJECTIVE
  To evaluate the association between intake of vitamins C, E, folate and beta-carotene and colorectal cancer risk, focusing on possibly different effects of dietary, supplemental and total intake, and on potential effect modification by lifestyle factors.
  
  
  METHODS
  In a prospective cohort study of 56,332 participants aged 50-64 years, information on diet, supplements and lifestyle was collected through questionnaires. 465 Colon and 283 rectal cancer cases were identified during follow-up. Incidence rate ratios of colon and rectal cancers related to micronutrient intake were calculated using Cox proportional hazard analyses.
  
  
  RESULTS
  The present study found a protective effect of dietary but not supplemental folate on colon cancer. No association with any other micronutrient was found. Rectal cancer did not seem associated with any micronutrient. For both colon and rectal cancer, we found an interaction between dietary folate and alcohol intake, with a significant, preventive effect among those consuming above 10g alcohol/day only.
  
  
  CONCLUSIONS
  This study adds further weight to the evidence that dietary folate protects against colon cancer, and specifies that there is a source-specific effect, with no preventive effect of supplemental folic acid. Further studies should thus take source into account. Vitamins C, E and beta-carotene showed no relation with colorectal cancer.
authors.affiliation: Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark. roswall@cancer.dk <roswall@cancer.dk>
authors.forename: Nina
authors.initials: N
authors.lastname: Roswall
authors.forename: Anja
authors.initials: A
authors.lastname: Olsen
authors.forename: Jane
authors.initials: J
authors.lastname: Christensen
authors.forename: Lars O
authors.initials: LO
authors.lastname: Dragsted
authors.forename: Kim
authors.initials: K
authors.lastname: Overvad
authors.forename: Anne
authors.initials: A
authors.lastname: Tjønneland
mesh_terms: D003110:Colonic Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D003718:Denmark / Q000453:epidemiology; D019587:Dietary Supplements / Q000009:adverse effects; D004435:Eating; D005260:Female; D006801:Humans; D008297:Male; D018977:Micronutrients / Q000008:administration & dosage*; D008875:Middle Aged; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: D018977:Micronutrients