The Efficacy of the Consumption of n-3 Polyunsaturated Fatty Acids for the Maintenance of Remission in Patients with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) represents a group of intestinal disorders that cause prolonged inflammation of the digestive tract. The two major types of IBD are ulcerative colitis (UC), which is limited to the colonic mucosa, and Crohn disease (CD), which can affect any segment of the gastrointestinal tract from the mouth to the anus, involves "skip lesions," and is transmural.

With respect to n-3 polyunsaturated fatty acids (PUFA), alpha-linolenic acid (ALA) is metabolized to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). N-3 PUFA are essential fatty acids present in large amounts in perilla oil and fish oils and inhibit the metabolism of n-6 PUFA by competitively antagonizing metabolic enzymes, such as delta 6- and delta 5-desaturases, cyclooxygenase (COX) and 5 lipoxygenase (LOX), thereby producing anti-inflammatory actions by inhibiting the synthesis of AA-derived inflammatory mediators and thromboxane A2 (TXA2). Therefore, it is thought that the regulation of the n-3/n-6 ratio with a therapeutic diet may be important for reducing disease activity in patients with IBD.

In this study, the authors aimed to investigate the efficacy of the actual consuming n-3 PUFA for remission-maintenance in IBD patients. A questionnaire on the dietary habits of patients one month before hospitalization (Q1) was completed by 24 patients with IBD (10 ulcerative colitis (UC) subjects and 14 Crohn’s disease (CD) subjects) treated at the hospital. The authors educated the study subjects about an n-3 PUFA diet, and a follow-up survey (Q2) was conducted 6 to 12 months after discharge. Disease activity was evaluated using the International Organization for the Study of Inflammatory Bowel Disease (IOIBD) score and/or the Crohn’s Disease Activity Index (CDAI) score for CD and the partial UCDAI score without endoscopic evaluation for UC.

Q1 showed that the average n-3 and n-6 PUFA intakes were 1673 ± 1651 mg and 9146 ± 5217 mg, respectively, and the average n-3/n-6 ratio was 0.27 ± 0.31. In Q2, the intake of n-3 PUFA was significantly higher (3671 ± 1684 mg, p < 0.001), whereas the n-6 PUFA intake decreased significantly (5217 ± 1973 mg, p < 0.001) compared to those in Q1. As a consequence, the dietary n-3/ n-6 ratio was significantly increased (0.87 ± 0.60, p < 0.001). Maintenance of the remission rate was significantly higher in IBD patients who complied with the n-3 diet, and these patients maintained a dietary n-3/n-6 ratio of 0.432 or higher (17 of 23 cases; 70.8%, p < 0.03) compared to that observed for IBD patients who did not comply with the diet.

In short, these results suggest that adherence to the n-3 diet and its impact on the maintenance of remission may be achieved by understanding the importance of adjustments to dietary PUFA.

Article by Kan Uchiyama, et al, from Japan.

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