Mechanisms of action.
Chitosan is believed to affect cholesterol levels and weight because it has positively charged amino groups at the same pH as the gas- trointestinal tract.
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 chito- san in cholesterol management may be explained by the theory that ingested chitosan salts react with fatty acids and bind lipids because of hydrophobic in- teractions; these bound lipids are ex- tracted rather than absorbed. Animal studies in rats, mice, and chickens indicate that chitosan decreases very-low-density- lipoprotein-cholesterol levels while increasing high-density-lipoprotein (HDL)-cholesterol levels.4 In vitro studies have also shown that O-carboxymethyl chitosan beads absorb low-density- lipoprotein (LDL) cholesterol.4