There are plausible mechanisms for how dietary docosahexaenoic acid (DHA), an n−3 polyunsaturated fatty acid, could prevent Crohn's disease (CD).
Dr Chan and colleagues from the United Kingdom conducted a prospective study to investigate the association between increased intake of DHA and risk of Crohn's disease.
Overall, 229,702 participants were recruited from 9 European centers between 1991 and 1998.
At recruitment, dietary intakes of DHA and fatty acids were measured using validated food frequency questionnaires.
The cohort was monitored through to 2004 to identify participants who developed incident Crohn's disease.
|The odds ratio trend across quintiles of DHA was 0.54|
|Alimentary Pharmacology & Therapeutics|
In a nested case–control analysis, each case was matched with 4 controls.
The research team calculated odds ratios for quintiles of DHA intake, adjusted for total energy intake, smoking, other dietary fatty acids, dietary vitamin D and body mass index.
The team noted that 73 participants developed incident Crohn's disease.
All higher quintiles of DHA intake were inversely associated with development of Crohn's disease.
The highest quintile had the greatest effect size.
The odds ratio trend across quintiles of DHA was 0.54.
Including BMI in the multivariate analysis, due to its correlation with dietary fat showed similar associations.
The researchers found no associations with the other dietary fatty acids studied.
Dr Chan's team concludes, "There were inverse associations, with a biological gradient between increasing dietary docosahexaenoic acid intakes and incident Crohn's disease."
"Further studies in other populations should measure docosahexaenoic acid to determine if the association is consistent and the hypothesis tested in randomized controlled trials of purely docosahexaenoic acid supplementation."