Dietary Factors in the Modulation of Inflammatory Bowel Disease Activity

Shinil Shah, DO, PGY-1


March 27, 2007

Iron/ Vitamin E/ Catechins

In several models of colitis, including an IL-10 deficient model and an iodoacetamide-induced model, iron supplementation has been shown to adversely affect inflammation. It is believed that this is due to the fact that free radicals are produced through the iron-catalyzed Fenton reaction. This poses a problem in part because the majority of ingested iron is not absorbed, and consequently the intestines receive a large amount of iron substrate.[30,31]

A significant proportion of patients develop iron-deficiency anemia secondary to blood loss, and hence, if the free radicals are clinically significant, iron supplementation may worsen inflammation. A study done by Carrier and colleagues[32] demonstrated that the supplementation of vitamin E to iron regimens reduced the adverse effect that iron had on colitis disease activity in a dextran sulfate sodium-induced colitis model.[32]

In addition to vitamin E (alpha tocopherol), catechins have been shown to have an anti-inflammatory effect in a trinitrobenzene sulfonic acid-induced model of ulcerative colitis.[33] Alpha tocopherol is an antioxidant, which may explain its effectiveness in colitis and also as a protective role when administered with iron, which is known to generate free radicals.[6]

Catechins are flavonoids. Flavonoids are noted to have a variety of functions, including anti-inflammatory, anti-allergic, antiviral, and anticarcinogenic actions. They are also believed to be antioxidants. Flavonoids are found in diverse food sources such as citrus fruits, berries, onions, parsley, legumes, green tea, and red wine.[6] Effects of catechins that may be beneficial in IBD include antioxidant and anti-endotoxin effects. Because of noted side effects such as autoimmune hemolysis, febrile reactions, and urticaria, care must be exercised when using this product and larger studies are warranted before this is accepted as a valid alternative therapy for IBD.[6]


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