People who eat a diet high in linoleic acid may be increasing their risk of ulcerative colitis. Foods richest in linoleic acid are red meat and certain types of cooking oil and margarines.
Ulcerative colitis is a lifelong, painful bowel disease, characterized by inflammation of the lining of the large intestine. Currently, there is no proven dietary treatment for the disease.
Linoleic acid is a member of a class of fatty acids known as omega−6 polyunsaturated fatty acids. Another class of polyunsaturated fatty acids, omega−3's, basically reduce inflammation.
Linoleic acid is an essential fatty acid, meaning that some is required in peoples' diets. However, many diets contain excessive amounts. Oils highest in linoleic acid are safflower, grape seed, poppy seed and sunflower. Canola, olive, palm and coconut oil are low in linoleic acid.
Hart notes that a red meat−heavy western diet is high in linoleic acid and low in omega−3 fatty acids. A Mediterranean style diet — high in fish, fruits and vegetables and nuts – is low in linoleic acid and high in Omega−3's. Hart estimates that if omega−3's do protect against ulcerative colitis, a couple of servings of fish a week would probably be protective.
The researchers looked at data from the EPIC trial, a multi−nation European trial. Using information from over 200,000 subjects in five countries, the study found 126 subjects who developed ulcerative colitis during the 2−11 years of follow−up. The dietary information from these subjects indicated that those whose diets contained the most linoleic acid (13−38 grams daily) were two and a half times as likely to develop ulcerative colitis as those who ate the least linoleic acid (2−8 grams daily).
This study only suggests that foods high in linoleic acid, such as red meat, may increase the risk of developing ulcerative colitis. Of the hundreds or thousands of compounds in red meat, the researchers focused on linoleic acid because of its known inflammatory properties.