What is Chitosan and why is it called a fat-blocker?
A. Chitosan is made by deacetylation of chitin , which is the structural element in the exoskeleton of crustaceans (crabs, shrimp, etc.). The degree of deacetylation (%DA) can be determined by NMR spectroscopy, and the %DA in commercial chitosans is in the range 60-100 %. In the human body, it actually behaves like a dietary fiber, since it is not absorbed and digested as such but passes into the large intestine where it can be fermented in much the same way as dietary fibers of plant origin. The reason it is called a fat-blocker is that it tends to prevent the digestion and absorption of fats. It is not clear whether binding bile acids is the main mechanism. or whether it achieves its effect by binding to the intestinal mucosa. In any case, the fat-blocking effect is relatively modest, and chitosan does not cause side-effects such as the unpleasant and sometimes dramatic side-effects seen with the pharmaceutical inhibitors of fat absorption such as orlistat (gastro-intestinal disturba
