Chitosan, produced by the deacetylation of chitin (a structural component of crustacean exoskeletons), is widely sold as a weight-loss product. These products claim that chitosan (or the soluble fibre produced when chitosan comes in contact with dilute acid in the stomach) can bind and reduce fat digestion and absorption to an extent that would promote weight loss. Of course, as a “natural” product, it is also promoted as being safe with no side effects and often backed with “testimonials” and wildly optimistic weight-loss claims.
So does chitosan actually work?
This question was the topic of a recent Cochrane Database Systematic Review by Andrew Jull and colleagues from the University of Aukland, New Zealand. The researchers searched electronic databases (MEDLINE, EMBASE, BIOSIS, CINAHL, The Cochrane Library), specialised web sites (Controlled Trials, IBIDS, SIGLE, Reuter’s Health Service, Natural Alternatives International, Pharmanutrients), bibliographies of relevant journal articles, and contacted relevant authors and manufacturers.
Trials were included in the review if they were randomised controlled trials of chitosan for a minimum of four weeks duration in adults who were overweight or obese. Authors of included studies were contacted for additional information where appropriate.
Fifteen trials including a total of 1219 participants met the inclusion criteria. Analyses indicated that chitosan preparations result in a statistically significantly greater weight loss of about 1.7 kg with a modest decrease in total cholesterol and blood pressure.
However, the authors note that the quality of many studies was sub-optimal and that when they restricted analyses to larger and longer studies, the effects were substantially smaller than in the smaller studies.
The authors conclude that while there is some evidence that chitosan may indeed be more effective than placebo in the short-term treatment of overweight and obesity, the results from the few high quality trials indicate that the effect of chitosan on body weight is minimal and unlikely to be of clinical significance.
Clearly not enough evidence for me to recommend chitosan to any of my patients - my advise to them: save your money for treatments that work.
AMS
Edmonton, Alberta
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