Chitosan for overweight or obesity
Editorial Group: Cochrane Metabolic and Endocrine Disorders Group
Published Online: 16 JUL 2008
Assessed as up-to-date: 31 AUG 2007
Copyright © 2008 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
How to Cite
Jull AB, Ni Mhurchu C, Bennett DA, Dunshea-Mooij CAE, Rodgers A. Chitosan for overweight or obesity. Cochrane Database of Systematic Reviews 2008, Issue 3. Art. No.: CD003892. DOI: 10.1002/14651858.CD003892.pub3.
- Publication Status: New search for studies and content updated (no change to conclusions)
- Published Online: 16 JUL 2008
Chitosan, a deacetylated chitin, is a dietary supplement reported to decrease body weight. It is widely available over the counter worldwide and although evaluated in a number of trials its efficacy remains in dispute.
To assess the effects of chitosan as a treatment for overweight and obesity.
We 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.
Data collection and analysis
Details from eligible trials were extracted independently by two reviewers using a standardised data extraction form. Differences in data extraction were resolved by consensus. Continuous data were expressed as weighted mean differences and standard deviations. The pooled effect size was computed by using the inverse variance weighted method.
Fifteen trials including a total of 1219 participants met the inclusion criteria. No trial to date has measured the effect of chitosan on mortality or morbidity. Analyses indicated that chitosan preparations result in a significantly greater weight loss (weighted mean difference -1.7 kg; 95% confidence interval (CI) -2.1 to -1.3 kg, P < 0.00001), decrease in total cholesterol (-0.2 mmol/L [95% CI -0.3 to -0.1], P < 0.00001), and a decrease in systolic and diastolic blood pressure compared with placebo. There were no clear differences between intervention and control groups in terms of frequency of adverse events or in faecal fat excretion. However, the quality of many studies was sub-optimal and analyses restricted to studies that met allocation concealment criteria, were larger, or of longer duration showed that such trials produced substantially smaller decreases in weight and total cholesterol.
There is some evidence that chitosan is more effective than placebo in the short-term treatment of overweight and obesity. However, many trials to date have been of poor quality and results have been variable. Results obtained from high quality trials indicate that the effect of chitosan on body weight is minimal and unlikely to be of clinical significance.
Plain language summary
Chitosan for overweight or obesity
Overweight and obesity are common health conditions worldwide but there are few effective treatments. Chitosan is a widely available dietary supplement that claims to aid weight loss and blood cholesterol levels. Fifteen studies which lasted between 4 to 24 weeks including a total of 1219 participants were analysed. Trials of chitosan to date have varied considerably in terms of quality. The review suggests that chitosan may have a small effect on body weight but results from high quality trials indicate that this effect is likely to be minimal.
電子資料庫(MEDLINE, EMBASE, BIOSIS, CINAHL, The Cochrane Library)，專科網站(Controlled Trials, IBIDS, SIGLE, Reuter's Health Service, Natural Alternatives International, Pharmanutrients)，相關的文獻、並與相關作者與出版商聯繫。
合格試驗之細節由兩位審核者分別獨立以標準化資料萃選形式所萃選出來的。資料萃選若有不同，則採共識決。連續性資料以權重平均差及標準差表示。集結後之有效大小以the inverse variance weighted method跑電腦。
15篇試驗裡面共有1219位受試者合乎收錄標準。迄今沒有一個試驗衡量甲殼素對死亡與罹病之影響。分析顯示甲殼素製品組與安慰組相比，有意義的降低體重(權重後，平均差別−1.7公斤, 95%信賴區間 (CI) −2.1 to −1.3 kg, P < 0.00001)；降低膽固醇[95% CI −0.3 to −0.1], P <0.00001)；與降低收縮及舒張壓。介入組與控制組在不良反應或糞便脂肪排泄之頻率沒有明顯差異。然而，許多試驗的品質不盡理想，若分析限定於合乎分配隱藏標準、較大型、或為期較長的試驗，那麼體重與膽固醇的降低就變小了。
此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。