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Cellulose fiber is a primary therapeutic candidate for IBS, and is a terrible choice for a placebo!

Posted by pwestep on 24 Dec 2010 at 18:02 GMT

avicel
http://plosone.org/article/info:doi/10.1371/journal.pone.0015591#article1.body1.sec2.sec3.p1

I agree with the concern expressed by A1kmm but think the situation is even more dire. IBS might be classified with a few others as a worst choice for such a study--especially with cellulose fiber as the choice of placebo. By definition, a cellulose filler is not going to be absorbed and will end up in the bowel, directly altering the environment most proximal to the etiology of the disease. Avicel doesn't have to be "active", per se, to change the bowel environment. As a point of speculation, it might be most effective in such a study if it is inert yet persists in the bowel, possibly protecting bowel tissue from microbial action. This has long been a point of speculation and fiber intake has been associated with improvement in IBS (see Zuckerman, PMID: 16394869), EXCEPT that placebo-controlled studies (typically using fiber-based placebos!) fail to show statistical significance. Sadly, this publication appears to be a continuation of this atrocious experimental design in which a primary therapeutic candidate is being used as a "placebo."

No competing interests declared.