July 23 (HealthDay News) -- Consuming too much of a common polyunsaturated fatty acid could be a contributing factor in an estimated 30 percent of all cases of ulcerative colitis, researchers say.

In a new study, participants who had the highest intake of linoleic acid had more than double the chance of developing the painful inflammation and blistering of the bowels as did those whose diet contained the least of the acid. The report is published online in Gut.

Red meat and some cooking oils and margarines are among the many dietary sources of linoleic acid.

However, the research also found that consuming lots of omega 3 fatty acids can cut the chance of developing ulcerative colitis by more than three quarters. Oily fish such as salmon and mackerel, flaxseed and certain dairy products are rich in omega 3, also known as docosahexanoic acid.

The European study, which looked at the dietary habits of more than 200,000 people in five countries, found that ulcerative colitis occurred about equally in men and women and at an average age of 60. The data analysis took into account other possible causes of the condition, including smoking, age, caloric intake and aspirin use.

The body converts linoleic acid to arachidonic acid, a component of the cell membranes in the bowel, and it then can turn into various chemicals that inflame tissue, according to information in a news release from the journal's publisher. People with ulcerative colitis have been found to have high levels of these chemicals in their bowel tissue.

Having ulcerative colitis, which is a chronic condition, puts a person at a higher risk of developing bowel cancer.

SOURCE: BMJ Specialist Journals, news release, July 22, 2009