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The effect of the dietary supplement, Chitosan, on body weight: a randomised controlled trial in 250 overweight and obese adults


CONTEXT: Chitosan, a deacetylated chitin, is a widely available dietary supplement purported to decrease body weight and serum lipids through gastrointestinal fat binding. Although evaluated in a number of trials, its efficacy remains in dispute.

OBJECTIVE: To evaluate the efficacy of chitosan for weight loss in overweight and obese adults.

DESIGN AND SETTING: A 24-week randomised, double-blind, placebo-controlled trial, conducted at the University of Auckland between November 2001 and December 2002.

PARTICIPANTS: A total of 250 participants (82% women; mean (s.d.) body mass index, 35.5 (5.1) kg/m2; mean age, 48 (12) y)

INTERVENTIONS: Participants were randomly assigned to receive 3 g chitosan/day (n=125) or placebo (n=125). All participants received standardised dietary and lifestyle advice for weight loss. Adherence was monitored by capsule counts.

MAIN OUTCOME MEASURES: The primary outcome measure was change in body weight. Secondary outcomes included changes in body mass index, waist circumference, body fat percentage, blood pressure, serum lipids, plasma glucose, fat-soluble vitamins, faecal fat, and health-related quality of life.

RESULTS: In an intention-to-treat analysis with the last observation carried forward, the chitosan group lost more body weight than the placebo group (mean (s.e.), −0.4 (0.2) kg (0.4% loss) vs +0.2 (0.2) kg (0.2% gain), P=0.03) during the 24-week intervention, but effects were small. Similar small changes occurred in circulating total and LDL cholesterol, and glucose (P<0.01). There were no significant differences between groups for any of the other measured outcomes.

CONCLUSION: In this 24-week trial, chitosan treatment did not result in a clinically significant loss of body weight compared with placebo.

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This study could not have been conducted without the dedication of Human Nutrition Unit staff (Jane Easton (Study Manager), Santuri Rungan, Chao-Yuan Chen, David Anderson, Laura Gerulitis, Pia Nielson, Jeannette Eis, Cathelijne Reincke, Shannon McCarthy) and staff at the Clinical Trials Research Unit involved in programming (Alex Bormans, Barry Gray, Donovan Marshall, Clark Mills, Colleen Ng, Michael Ng, Jaco van Rooyen), data management (Michelle Barlow, Yvonne Cleverley, Terry Holloway, Daphne Hukui, Amanda Milne, Ellen Rhyno, Marissa Te Whui, Esther Vao, Sandhya Waghulde, Alison Young) and administrative support (Mary Cosson, Deanne Douglas, Sheila Fisher, Elizabeth Hawthorne). We would like to thank our Data Safety and Monitoring Committee (Katrina Sharples and Jim Mann), and we are particularly grateful for the contribution of the 250 ECHO study participants. This was an investigator-initiated study funded predominantly by the Health Research Council of New Zealand. Study treatments and funding for vitamin analyses was provided by Healtheries of New Zealand Ltd. CNM and AR held fellowships from the National Heart Foundation of New Zealand.

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Correspondence to C Ni Mhurchu.

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Mhurchu, C., Poppitt, S., McGill, AT. et al. The effect of the dietary supplement, Chitosan, on body weight: a randomised controlled trial in 250 overweight and obese adults. Int J Obes 28, 1149–1156 (2004).

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