Sunday, June 16, 2013

IBD and Fish Oil


Omega-3 Fatty Acids, Crohn's, and Ulcerative Colitis


One of the most touted diet supplements for general good health is Omega-3 fatty acids (n-3 acids).  Generally available in pill form and sold as “fish oil”, they have been presented to the general public as having tremendous health benefits ranging from cardiovascular improvement to lowering the risk of stroke.  They have also been put forth as a part of maintenance regimes for both Crohn’s Disease and Ulcerative Colitis.  This post will look at the evidence of efficacy and safety in taking omega-3 fatty acid supplements as a maintenance treatment for inflammatory bowel disease and won’t address the benefits/risks if any in taking them to treat other conditions.

n-3 acids are polyunsaturated fats found naturally occurring in a variety of foods, with fish having the highest levels.  A single serving of salmon has over 1 gram of n-3 acids, flounder has .5 grams, and shrimp and crabs both have around .25 grams.  Other foods contain n-3 acids also, with eggs topping out the charts at .1 gram per egg.  Diets high in seafood have generally been shown to have positive coronary effects, and n-3 acids are believed to be part of that positive impact (there are other positives to eating certain types of fish also – including having low fat and avoiding other types of food with poor diet profiles).(1)

The mechanism for action in n-3 acids with IBD is the reduction of proinflammation cytokines.  Baseline studies in humans showed that triglycerides were reduced with the intake of n-3 acids in Crohn’s disease patients, along with epidemiological evidence showing a low incidents in Eskimo populations where a fish heavy diet is prevalent (though the studies don’t isolate fish or fish oil).(2,3)  Further, animal studies showed lesion healing commensurate with the intake of n-3 supplements.(4)

The first major study to address fish oil supplements, an enteric-coated capsule was provided to a small sample of Crohn’s patients prospectively in a double-blind, placebo controlled study of 78 patients (39 controls).  The fish oil group showed higher rates of remission, though there were a few individuals that dropped out and the sample size was small.(5)  Similar early studies with Ulcerative Colitis showed no maintenance effect, but did show a small effect in inducing remission.(6)

Unfortunately, the initial study results did not hold up when larger studies were conducted (notably the EPIC studies).  Reviews of the well-designed studies showed no significant result from taking Omega-3 fatty acids with either Ulcerative Colitis or Crohn’s Disease, and found a likelihood of publication bias (not publishing negative results).  While the smaller studies had mixed results, the larger studies showed no statistical impact in taking fish oil for IBD.(7)  There is still some room for experimentation – there may be different dosing or delivery mechanisms with higher efficacy, but they haven’t come out yet in the evidence.

Omega-3 supplements have not been shown to have any major side effects, however two of the minor side effects are of particular interest to those with IBD.  Both diarrhea and upper GI upset are common side effects, and caused drop-outs in several of the studies noted above. 

The lack of efficacy of omega-3 fatty acids in maintaining remission in IBD is disappointing.  That said, there is no reason to stop eating fish as a regular part of your well balanced diet.  Salmon and flounder are excellent sources of lean protein.  I recommend trying cedar plank cooking of both (if you have not tried it, Google “cedar plank salmon”) now that the grilling season is upon us!

Bottom Line

·         Omega-3 fatty acid supplements have no statistically significant effect on IBD remission based on the current research.
·         While the side effects of fish oil supplements are minor, the most common – diarrhea and upper GI upset, can effect quality of life in Crohn’s and UC patients.
·         Eating fish is still recommended as part of a well-balanced diet – skip the supplements, eat the fish.

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2.       Belluzzi, A., C. Brignola, M. Campieri, E. P. Camporesi, P. Gionchetti, F. Rizzello, C. Belloli et al. "Effects of new fish oil derivative on fatty acid phospholipid-membrane pattern in a group of Crohn's disease patients."Digestive diseases and sciences 39, no. 12 (1994): 2589-2594.
3.       Belluzzi, Andrea, Stefano Boschi, Corrado Brignola, Alessandra Munarini, Giulio Cariani, and Federico Miglio. "Polyunsaturated fatty acids and inflammatory bowel disease." The American journal of clinical nutrition 71, no. 1 (2000): 339s-342s.
4.       Vilaseca, J., A. Salas, F. Guarner, R. Rodriguez, M. Martinez, and J. R. Malagelada. "Dietary fish oil reduces progression of chronic inflammatory lesions in a rat model of granulomatous colitis." Gut 31, no. 5 (1990): 539-544.
5.       Belluzzi, Andrea, Corrado Brignola, Massimo Campieri, Angelo Pera, Stefano Boschi, and Mario Miglioli. "Effect of an enteric-coated fish-oil preparation on relapses in Crohn's disease." New England Journal of Medicine 334, no. 24 (1996): 1557-1560.
6.       Hawthorne, A. B., T. K. Daneshmend, C. J. Hawkey, A. Belluzzi, S. J. Everitt, G. K. Holmes, C. Malkinson, M. Z. Shaheen, and J. E. Willars. "Treatment of ulcerative colitis with fish oil supplementation: a prospective 12 month randomised controlled trial." Gut 33, no. 7 (1992): 922-928.
7.       Turner, Dan, Prakesh S. Shah, A. Hillary Steinhart, Stanley Zlotkin, and Anne M. Griffiths. "Maintenance of remission in inflammatory bowel disease using omega3 fatty acids (fish oil): A systematic review and metaanalyses."Inflammatory bowel diseases 17, no. 1 (2011): 336-345.

1 comment:

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