Dietary Factors in the Modulation of Inflammatory Bowel Disease Activity

Shinil Shah, DO, PGY-1


March 27, 2007

Dietary Fat

The amount of fat in enteral diets has been shown to affect remission rate. It is also believed that the type of fat may play a role. When a meta-analysis was performed looking at the rate of remission as compared to the amount of fat in enteral feedings, it was shown that fat content and remission rate were inversely related. But it was predominantly long-chain triglycerides that appeared to have this adverse effect. When medium-chain triglycerides were added, there was no noted adverse effect on remission rate.

The determination as to whether a triglyceride is classified as a long or short chain is based on the number of carbons the fatty acids contains. Greater than 12 carbons in a fatty acid signifies a long-chain triglyceride, and between 6 and 12 carbon atoms classifies it as a medium chain. Medium-chain triglycerides are digested and absorbed more completely than their long-chain counterparts, and are water soluble. Medium-chain triglycerides are found in coconut oil, whereas safflower and soybean oil are good sources of long-chain triglycerides.[17]

Other small studies have shown that low-fat diets and diets with medium-chain triglycerides are superior to higher fat diets in the induction and maintenance of remission.[18,19]

Case control studies have shown that ulcerative colitis may be associated with an increased intake of monosaturated and polyunsaturated fats. It has been also shown that omega-6 fatty acids are positively correlated with IBD, whereas omega-3 fatty acids are negatively correlated.[3,20] Omega-6 fatty acids are the precursor to synthesis of arachidonic acid, which is degraded into powerful mediators of inflammation by phospholipase A2.[14] However, omega-3 fatty acids compete with omega-6 fatty acids in the synthesis pathway of arachidonic acid, thereby decreasing its synthesis, and subsequently the synthesis of inflammatory mediators.

Sources of omega-3 fatty acids include fish, fish oil, algae, walnuts, leafy green vegetables, flax, and canola oils. Sources of omega-6 fatty acids include corn, soy, primrose, sunflower and safflower oils, red meat, and borage.[21,22] Various studies have shown that administration of omega-3 fatty acids has a positive effect on IBD.[3,20,22,23,24,25]


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