Essential fatty acids found in fish oil (search) could help cut inflammation in people with Crohn’s disease (search), an inflammatory bowel disease.

Though the cause of Crohn's disease is unknown, the inflammation is triggered by an overactive immune system within the walls of the bowel.

The disease can go into remission, though it may flare up several times throughout a patient’s life.

The flare-ups may accompany medications, infections, hormonal changes, lifestyle changes (including increased stress), and smoking. Crohn’s has no cure, but medications and surgery are used to manage it.

The British study, recently published in the American Journal of Clinical Nutrition, tested fish oil’s anti-inflammatory effects on white blood cells from patients with Crohn's disease.

The researchers, who included Timothy Trebble of the Institute of Human Nutrition at England’s University of Southampton, wanted to see if fish oil could affect markers of inflammation in these white blood cells.

They were especially interested in two key components of fish oil: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Both are omega-3 fatty acids (search), polyunsaturated fatty acids that have been shown to have a number of health benefits.

You may have heard about omega-3s before. They’ve gotten a lot of attention in recent years, with researchers testing them on conditions including depression and heart disease. Earlier this year, the FDA said it would allow labels on foods and supplements containing EPA and DHA to say that such items could help cut the risk of heart disease when they are substituted for unhealthy fats in the diet.

The researchers gave fish oil supplements containing 2.7 grams of EPA and DHA — along with several antioxidants (selenium, manganese, and vitamins A, C, and E) — to 31 adults with Crohn’s disease. An equal number of patients took a placebo containing olive oil.

Participants took their supplements every day for 24 weeks. Blood samples showed that white blood cells from the fish oil group produced fewer markers of inflammation. The fish oil group had more EPA and DHA in those cells.

The results are probably due to EPA and DHA, not the antioxidants, say the researchers. They suggest that fish oil supplements might fight Crohn’s complications beyond the digestive system.

Fish oil supplementation deserves more study for its impact on Crohn’s, say the researchers. Meanwhile, you can also get EPA and DHA directly from fatty fish like salmon, herring, sardines, and mackerel.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Trebble, T. American Journal of Clinical Nutrition, November 2004; vol 80: pp 1137-1144. WebMD Medical Reference from Healthwise: “Crohn’s Disease: Topic Overview.” WebMD Medical Reference from Healthwise: “Crohn’s Disease: What Happens.” WebMD Medical News: “Omega-3 Fatty Acids Get New Health Claim.” WebMD Medical News: “The Benefits of Fish Oil.”