Chitosan Affecting Blood Lipids

Chitosan and its use as a weight loss aid and cholesterol lowering agent has long been the favorite topic of considerable study in the last several decades. Numerous reports have noted that an increasing chitosan intake usually leads to decreased serum cholesterol levels as well as increased ratios of high density to low density lipoproteins which is well documented to be protective against cardiovascular diseases.

Along with the noted fat and cholesterol lowering effects of chitosan, several claims have emerged stressing the effects of chitosan on blood lipids. Chitosan, as you may know, is made by deacetylation of chitin, the cellulose-like material found in the outer shells of insects, crabs, lobsters, and other crustaceans, as well as in fungal cell walls. Unlike most plant fibers, chitosan is known for having positively charged amino groups which form ionic bonds with lipids and bile components.

The mechanism of how chitosan affecting blood lipids await elucidation. However, the mechanism is most likely mediated by the chitosan actions on micelle formation in the gut. Micelle is basically the lipid transporter. According to some experts, the mixed micelles in the gastrointestinal tract contain free fatty acids, cholesterol and other components. It is also the method by which lipids are absorbed into the blood stream. Perhaps what supports the idea of chitosan affecting blood lipids is the fact that chitosan acts by binding to the free fatty acids and bile acid components, thus removing them from the micelles and disrupting the absorption of lipids.

Numerous studies have been conducted to reveal the real score of chitosan affecting blood lipids. These studies were conducted in both animals and humans, and the effects have generally been more dramatic in various animal models. Perhaps this is due to higher chitosan intake in many of the studies. However, some of the studies also show very dramatic reductions on cholesterol as well in LDL cholesterol levels. And, there are some that showed increases in the HLD cholesterol, as well.

Studies conducted in humans have gathered results that have been less clear-cut, though some still suggestive of positive effects. One particular study conducted to find out if the claims on chitosan affecting blood lipids are true is the recent placebo-controlled, double-blind study which noted that there was a significant decrease in LDL cholesterol among subjects receiving 2,4000 milligrams of chitosan daily, compared with placebo subjects. Nevertheless, it was found out that chitosan had no significant effect on the serum total cholesterol or on HDL, but it slightly increased triglycerides. Other studies have reported similar lipid effects, but a few others have reported that the claims on chitosan affecting blood lipids are not at all valid. Perhaps, these differences are due to the dissimilarity in the dosage of chitosan given.

One means by which chitosan is thought to affect lipids and cholesterol levels is by altering the metabolism of bile in the gut. This has actually been documented in most animal studies, and some of the results appear to confirm the claims on chitosan affecting blood lipids.