Chitosan, the favorite fat blocker of late night television advertisements, has graced the shelves of health stores for some time now. Chitosan has even spawned a book (The Fat Blocker Diet, by Arnold Fox and Brenda Adderly), trumpeting its wondrous fat-burning powers.
So what is Chitosan?
Well, it’s a fiber supplement derived from the shells of crustaceans. Apparently, Chitosan had the amazing ability to bind with fat (we’ve all seen the demonstrations on the infomercials), and prevent it from being absorbed into the body. Once again, it appeared like the miracle weight loss drug had been discovered. Eat what you want, and lose all the weight you want… the dieter’s dream, right?
Well, as you may have guessed. there is a catch. The initial studies on the effectiveness of chitosan were performed on animals. In all fairness, they did seem to indicate a fat-absorbing tendency.
But as we’ve seen many times before, making the “jump” from animals to humans without adequate testing and verification does not always prove fruitful.
And therein lies the rub…
Smelling the truckloads of dollars waiting to be harvested, numerous manufacturers began producing and advertising this “fat blocker supplement”, without any corroboration of beneficial effects in humans. They also began to seriously exaggerate the claims of their product’s effectiveness. Before long, this got them into hot water with the U.S. Federal Trade Commission (The FTC has since taken action against several big-name manufacturers — click here for details one such action and click here for details on another).
In the wake of this, obesity researcher Dr. Judy Stern (cofounder of the American Obesity Association, member of the obesity task force of the National Institute of Health), from the University of California, Davis was recruited to do a study into the “fat blocking” effectiveness of this controversial supplement. What did she find? Contrary to results garnered in animal studies, Dr. Stern concluded Chitosan didn’t block fat absorption… not even a tiny little bit. And this study was the most intensive ever conducted.
Carefully documenting what went into and what came out of the test subjects (that’s putting it delicately, this was not a pleasant task!), Dr. Stern was able to establish that Chitosan had NO ability to bind with fat and eliminate it from the body. Of course, lawyers for the manufacturers of Chitosan-based products are contesting the study’s results. Unfortunately for them, Dr. Stern’s credibility as a researcher means there’s little hope they’ll be successful.
Lately of course, further studies have validated her conclusions (see Int J Obes Relat Metab Disord. 2004 Sep;28(9):1149-56, Cochrane Database Syst Rev. 2005 Jul 20;(3):CD00389, Singapore Med J. 2001 Jan;42(1):6-102, J Am Coll Nutr. 2006 Oct;25(5):389-94).
Unfortunately, this hasn’t prevented Chitosan from being continuing to be marketed by some “less than scrupulous” retailers as a natural “fat blocker.”
On the other hand, there does seem to be some positive news about Chitosan. Despite the largely negative results from study results, there does seem to be some evidence that it can positively effect cholesterol. In other words, it seems to have a positive effect on raising “good” (HDL) cholesterol levels, while lowering the undesirable LDL levels.
Nonetheless, Chitosan based fat blockers can hardly be described as a rip-roaring success. People who want fat blockers generally want to be able to fit into smaller clothes, and care less about “intangible” benefits like a lowered LDL level.
And despite what you may think, a pill that indiscriminately blocks fat is not necessarily a good idea. Certain vitamins (E,A,D,F,K) are fat-soluble, and extended Chitosan use could lead to deficiencies in them. Fat too, of course, is required for optimum bodily health, especially the Omega 3-6-9 fatty acids. Again, even if Chitosan were a viable fat blocker (and all the evidence suggests it is not), it would block these vital fats as well.