High dietary linoleic acid implicated in ulcerative colitis
MedWire News: A diet rich in linoleic acid could be linked to the development of ulcerative colitis (UC), a European study suggests.
People eating the highest levels of n-6 polyunsaturated acid, which is found in foods such as red meat and cooking oils, were more than twice as likely to develop UC as those eating the lowest amounts.
Lead researcher A Hart (University of East Anglia, Norwich, UK) and colleagues say: “If the association is causative then 30% of all cases could be attributed to such higher intakes.”
The findings come from a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) study, which included more than half a million volunteers from 23 centers in 10 countries.
In the current analysis, researchers studied food frequency questionnaires for 203,193 EPIC men and women aged 30 to 74 years living in the UK, Sweden, Denmark, Germany or Italy.
Over a mean follow-up of 4.0 years, 126 of these individuals, 47% of whom were women, developed UC. Each case was compared with four control individuals from the diagnosing center, matched for age and gender.
The highest quartile of linoleic acid intake (12.6–37.5 g/day for men and 14.9–35.4 g/day for women) was associated with a significantly increased risk of UC, with an odds ratio (OR) of 2.49 compared with the lowest quartile (1.9–6.1 g/day for men and 3.1–7.8 g/day for women), after adjusting for potential confounders.
Furthermore, there was a significant trend across quartiles, with an OR of 1.32 per category increase in intake.
The researchers note that linoleic acid is metabolized to arachidonic acid, which is a component of colonic cell membranes, and that arachidonic acid metabolites have pro-inflammatory properties and are increased in the mucosa of UC patients.
Reporting in the journal Gut, they suggest: “If the positive association is causal, then there is substantial potential for reducing the incidence of ulcerative colitis through dietary modification.”
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By Anita Wilkinson