Diet high in omega-6 fats increases risk for ulcerative colitis
Ulcerative colitis falls under the category of inflammatory bowel diseases (IBD). It is an autoimmune disease in which excessive inflammation kills cells in the lining of the colon, leaving ulcers behind. Ulcerative colitis is a chronic condition that commonly causes abdominal pain and bloody diarrhea, and it carries with it an increased risk of colorectal cancer. In some severe cases, the colon must be surgically removed. Clearly, this condition also causes a great deal of emotional trauma.1
Recent studies have identified dietary patterns that may predispose individuals to ulcerative colitis. High intake of fats, refined sugars, and fried potato products were positively associated with ulcerative colitis, and fruit consumption was found to be protective.2
Most recently, omega-6 fatty acids have been investigated. Omega-6 fatty acids are essential fatty acids, meaning that we must obtain them from our diet for good health, but the typical American diet contains an excessive amount of omega-6, which can produce a pro-inflammatory environment in the body.
Linoleic acid is an omega-6 fat that is highly concentrated in red meat, cooking oils, and margarines. In the digestive system, linoleic acid is metabolized into arachidonic acid, which incorporates into cell membranes of the colon. When arachidonic acid is broken down further, its products are pro-inflammatory – these products are found in excess in the intestinal cells of patients with ulcerative colitis. For these reasons, scientists believed that excess linoleic acid might be linked to ulcerative colitis risk.
A prospective study of over 200,000 men and women in Europe found that the subjects who consumed the highest levels of omega-6 linoleic acid were 2.5 times more likely to be diagnosed with ulcerative colitis. The researchers also found a negative association between the omega-3 fatty acid DHA and ulcerative colitis – subjects in the highest level of DHA intake decreased their risk by 77%.3
Avoiding excess levels of linoleic acid is simply accomplished by eating a diet that is based on whole plant foods and limits animal products and added fats. A diet of natural whole foods provides us with omega-6 fatty acids in appropriate amounts - not in excess – producing an anti-inflammatory environment.
For those who already have ulcerative colitis, it is important to know that the condition can be improved and sometimes completely resolved with dietary changes – conventional treatment of IBD often includes immunosuppressive drugs with dangerous side effects. Specific dietary recommendations for sufferers of IBD are outlined in the Inflammatory Bowel Disease newsletter.
2. Shah S. Dietary Factors in the Modulation of Inflammatory Bowel Disease Activity. MedGenMed 2007; 9(1):60
3. Tjonneland A et al. 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. IBD in EPIC Study Investigators. Gut. 2009 Dec;58(12):1606-11. Epub 2009 Jul 23.