Dietary n-3 polyunsaturated fatty acids and the aetiology of ulcerative colitis: a UK prospective cohort study

Eur J Gastroenterol Hepatol. 2010 May;22(5):602-6. doi: 10.1097/MEG.0b013e3283352d05.


Objectives: The aetiology of ulcerative colitis (UC) is largely unknown, although it is plausible that dietary n-3 polyunsaturated fatty acids (PUFAs) may be protective. Metabolites derived from n-3 PUFAs are less proinflammatory than those from n-6 PUFAs. Earlier, no prospective cohort studies have investigated this hypothesis, using dietary information collected from food diaries. The aim of this study was to investigate the total dietary intake of n-3 PUFAs and the specific n-3 PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the risk of developing incident UC.

Methodology: Twenty-five thousand six hundred and thirty-nine participants, living in Norfolk UK, aged 45-74 years (median age at recruitment of 59.2 years), completed 7-day food diaries. These were interpreted using a computer programme, which converted food items into nutrients, including n-3 PUFAs. The cohort was monitored for participants who developed UC. Each case was matched with four controls and an analysis performed using conditional logistic regression.

Results: In the cohort, 22 incident cases of UC were identified after a median follow-up time of 4.2 years (range 1.8-8.3 years). A statistically significant protective odds ratio (OR) for the trend across tertiles was found for DHA [OR = 0.43, 95% confidence interval (CI)=0.22-0.86, P = 0.02] and borderline statistically significant differences for trends for total total n-3 PUFAs (OR = 0.56, 95% CI=0.28-1.13, P = 0.10) and EPA (OR = 0.53, 95% CI=0.27-1.03, P = 0.06) after adjusting for age, sex, total energy intake, smoking, and other fatty acids.

Conclusion: Total dietary n-3 PUFAs, EPA, and DHA, particularly DHA were associated with protection from UC in a cohort aged over 45 years. If the association is causal, then increasing the population's intake of n-3 PUFAs from oily fish may help prevent UC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Cohort Studies
  • Colitis, Ulcerative* / epidemiology
  • Colitis, Ulcerative* / etiology
  • Colitis, Ulcerative* / prevention & control
  • Databases, Factual
  • Diet Records
  • Dietary Fats, Unsaturated / administration & dosage*
  • Dietary Supplements
  • Docosahexaenoic Acids / administration & dosage
  • Eicosapentaenoic Acid
  • Fatty Acids, Omega-3 / administration & dosage*
  • Fatty Acids, Unsaturated / administration & dosage
  • Female
  • Fish Oils / administration & dosage*
  • Follow-Up Studies
  • Humans
  • Incidence
  • Male
  • Middle Aged
  • Prospective Studies
  • Risk Factors
  • United Kingdom / epidemiology


  • Dietary Fats, Unsaturated
  • Fatty Acids, Omega-3
  • Fatty Acids, Unsaturated
  • Fish Oils
  • Docosahexaenoic Acids
  • Eicosapentaenoic Acid