Chitosan for Weight Loss and Cholesterol Management

Kelly M. Shields, Pharm.D., Nick Smock, Pharm.D., Cydney E. McQueen, Pharm.D., Patrick J. Bryant, Pharm.D., FSCIP


Am J Health Syst Pharm. 2003;60(13) 

In This Article

Pharmacology and Mechanisms of Action

Chitosan, the deacetylated polymer of N-acetyl-D-glucosamine (chitin), is water soluble and chemically similar to cellulose.[4] It occurs naturally in fungi, yeasts, marine invertebrates, and arthropods. Chitosan is the principal component of exoskeletons of marine crustaceans, from which supplements are often derived.[7]

Chitosan may be considered a cellulose-like dietary fiber; therefore, minimal digestion occurs, and most ingested chitosan is excreted fecally.[8]

Chitosan is believed to affect cholesterol levels and weight because it has positively charged amino groups at the same pH as the gastrointestinal tract.[4] These amino groups are believed to bind to negatively charged molecules, such as lipids and bile, preventing their absorption and storage by the body. The action of chitosan in cholesterol management may be explained by the theory that ingested chitosan salts react with fatty acids and bind lipids because of hydrophobic interactions; these bound lipids are extracted rather than absorbed.[9] Animal studies in rats, mice, and chickens indicate that chitosan decreases very-low-densitylipoprotein-cholesterol levels while increasing high-density-lipoprotein (HDL)-cholesterol levels.[4] In vitro studies have also shown that O-carboxymethyl chitosan beads absorb low-densitylipoprotein (LDL) cholesterol.[4]


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