Chitosan for Weight Control

What is it?

Chitosan is a polysaccharide found in the shells of crustaceans.

Where is it found?

Chitosan is extracted from the shells of crustaceans, such as shrimp and crab.

Why do dieters use it?*

Some dieters say that chitosan

helps decrease appetite.

What do the advocates say?*

Chitosan has been shown to inhibit fat absorption in animals, although in studies in humans chitosan did not inhibit fat absorption. Some research has found that taking chitosan during a weight loss programme increases the amount of weight loss. In other studies, however, chitosan was ineffective.

It is important to note that supplementing with chitosan will also cause the body to excrete the important fat-soluble vitamins A, D, E, and K, too.

How much is usually taken by dieters?

A double-blind Polish study found that people taking 1,500 mg of chitosan three times daily during a weight loss programme lost significantly more weight than people taking a placebo with the same programme.¹ Other studies using smaller amounts of chitosan have reported no effects on weight loss.² ³ ⁴

Are there any side effects or interactions?

While no long-term studies of the effects of chitosan on human health have been done, animal studies suggest that this compound could inhibit the absorption of minerals and fat-soluble vitamins. Adverse effects on the growth of children and on the outcome of pregnancy are also possible.⁵ In addition, although chitosan-included alterations in intestinal flora are believed to be beneficial, the possibility that these changes may have negative long-term consequences has not been ruled out. People with intestinal malabsorption syndromes should not use chitosan.

At the time of writing, there were no well-known drug interactions with chitosan.

Resources

See a list of books, periodicals, and other resources for this and related topics.

*Dieters and weight-management advocates may claim benefits for chitosan based on their personal or professional experience. These are individual opinions and testimonials that may or may not be supported by controlled clinical studies or published scientific articles on chitosan. For more complete and detailed information, including references and safety information, see Chitosan as a nutritional supplement.

References

1. Zahorska-Markiewicz B, Krotkiewski M, Olszanecka-Glinianowicz M, Zurakowski A. Effect of chitosan in complex management of obesity. Pol Merkuriusz Lek 2002;13:129–32 [in Polish].

2. Ho SC, Tai ES, Eng PH, et al. In the absence of dietary surveillance, chitosan does not reduce plasma lipids or obesity in hypercholesterolaemic obese Asian subjects. Singapore Med J 2001;42:006–10.

3. Pittler MH, Abbot NC, Harkness EF, Ernst E. Randomized, double-blind trial of chitosan for body weight reduction. Eur J Clin Nutr 1999;53:379–81.

4. Muzzarelli RA. Clinical and biochemical evaluation of chitosan for hypercholesterolemia and overweight control. EXS 1999;87:293–304 [review].

5. Koide SS. Chitin-chitosan: properties, benefits and risks. Nutr Res 1998;18:1091–101 [review].

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires August 2007.