A research published ahead of print in Gut (International Journal of Gastroenterology and Hepatology) reports that high intakes of linoleic acid might be associated to a third of ulcerative colitis cases. Linoleic acid is a common dietary polyunsaturated fatty acid (N-6 PUFA).

Ulcerative colitis has been linked to other complications, including an increased risk of bowel cancer. It is a painful chronic condition, in which the lining of the bowel becomes severely inflamed and blistered.

Linoleic acid is found in many dietary sources, such as red meat, various cooking oils, and some types of margarine.

The researchers studied food diaries which are food frequency questionnaires. More than 200,000 people were included in the research. The participants were all between the ages of 30 and 74 from the UK, Germany, Italy, Sweden and Denmark.

In the European Prospective Investigation into Cancer (EPIC) study, the participants were coordinated with four comparison groups of people without ulcerative colitis, and monitored for the development of the condition.

Overall, there were 126 people who developed ulcerative colitis after an average period of four years. The average age at diagnosis was sixty. Almost half the cases occurred in women (47 percent).

The researchers evaluated all the factors that could possibly have an effect on the results, such as smoking, age, total energy intake, and use of aspirin. The participants whose diets included the most linoleic acid were almost 2.5 times as likely to develop the condition as those whose diets contained the least.

The authors point out that if indeed there is a causal link, just about a third of cases (30 percent) of ulcerative colitis could be attributable to high intakes of linoleic acid.

When it is absorbed in the body, linoleic acid is transformed to arachidonic acid, which is a component of the cell membranes in the bowel.

Arachidonic acid can then be converted into various inflammatory chemicals. High levels of these chemicals have been found in the bowel tissue of patients with ulcerative colitis.

In addition, the research establishes that the highest intake of omega 3 fatty acid also known as docosahexanoic acid reduced the probability of developing ulcerative colitis by 77 percent. Omega 3 fatty acid is found in oily fish such as salmon and herring.

“Linoleic acid, a dietary n-6 polyunsaturated fatty acid, and the aetiology of ulcerative colitis: a nested case-control study within a European prospective cohort study”
Online First Gut 2009; doi 10.1136/gut.2008.16908
Gut bmj.com

Written by Stephanie Brunner (B.A.)