Chitosan is produced by the hydrolysis of chitin, a naturally occurring polysaccharide that is a major component of shellfish shell and the most plentiful natural polymer next to cellulose. As demonstrated by the following scientific papers, significant attention has been given to the role of Chitosan as a cholesterol and lipid binding agent. In acid media, Chitosan solubilizes and develops positively charged sites along its entire polymeric structure. Once soluble, it is theorized that Chitosan's ability to emulsify dietary fat in the stomach followed by its gelation in the gastrointestinal tract enables it to encapsulate significant amounts of dietary fat and negatively charged lipids. This gel with its entrapped lipids would then be eliminated as waste.

Although several possible mechanisms have been proposed to explain the inhibitory effect of Chitosan on lipid absorption, the presence of repeating amino groups throughout its polymeric structure appears to be key to its functionality.

Chitosan is soluble in stomach acid due to the protenation of its amino acid groups by the weak acid. In its soluble, positively charged state, Chitosan is a powerful emulsifier of dietary fat. This emulsification of fat occurs over the entire time that the soluble chitosan remains in contact with the food in the stomach.

As the Chitosan/dietary fat emulsion moves into the small intestine, it is also believed to bind with bile acids and cholesterol that are present. Such a complex could absorb up to 400 times its weight in water and would be expected to floc due to the higher, less acidic pH in the small intestine. It follows that this flocculation could further aid the binding process by potentially encapsulating most of the bound lipids, including cholesterol.

As the pH continues to increase, the Chitosan floc would form an insoluble gel consisting of Chitosan, bile acids, bound lipids and cholesterol. The gelation and subsequent insolubility of the Chitosan complex would protect the bound lipids from enzymatic action by lipase. The insoluble gel and its contents would then pass through to the large intestine and are ultimately excreted.

Not only is fat and cholesterol uptake potentially decreased but it is further postulated that the continuous partial removal of bile acids from circulation by Chitosan triggers the body to produce replacement bile acids via the oxidation of already absorbed cholesterol. This could explain any additional reduction in low density lipoprotein (LDL) and resulting overall decrease in serum cholesterol levels.

Chitosan’s fat binding properties are not shared with chitin which is not soluble in stomach acid. Nor does Chitosan share its fat binding/emulsification properties with other naturally occurring dietary fibers, including those that have historically been used for weight management. Such fibers are either negatively charged or neutral and, while swelling extensively in the gut, do not emulsify lipids nor prevent their digestion. These fibers include Konjac, cellulose, kapok, acacia, agar, carrageenan, furcellaran, guar, karaya, locust bean, pectin, and sodium alginate.