CHITOSAN
Chitosan has been popular in nutritional industry for years. What makes
it so popular in the industry? What is its benefit?
WHAT IS CHITOSAN / CHITIN?
Chitin is a natural biopolymer derived from exoskeletons of crustaceans and also from cell walls
of fungi and insects. Chitin is a linear beta 1,4-linked polymer of N-acetyl-D-glucosamine
(GlcNAc). Chitosan is different from chitin; chitosan is a collective name representing a family of
de-N-acetylated chitins deacetylated to different degrees. Both chitin, chitosan and their modified
derivatives have been applied in medicine, agriculture, food, and non-food industries. [1]

WHAT ARE THE HEALTH BENEFITS OF CHITOSAN?
Chitosan is particularly interested in the nutritional industry when it was introduced into the market
in the 1990s. Health food supplement manufacturers suggested its potential as a nutritional
adjunct for weight management. They emphasized favorable results from a few studies; they
claimed that chitosan was a beneficial effect on weight loss, cholesterol, ulcers, osteoporosis
and blood pressure. They hypothesized that the electrical charges that chitosan carries may bind
to the negative charges on bile acids and fatty acids, resulting in the hypocholesterolemic
(cholesterol lowering) effect. In addition to enhancing cholesterol excretion, this ionic bonding
resulted in excretion of fat, along with its associated phospholipids, monoglycerides and other
fatty acids.

How much chitosan should a person take to be effective to prevent the fat absorption? If a person
ingests two pounds of New York Steak, will 1 g of chitosan be enough? As this is a swelling
polymer, definitely, we don't want to take too much of chiton  to block our GI tract!! This article is
not suggesting that chitosan supplements have no benefit on weight management. In fact, a
recent review article assessed results of 14 randomized controlled trials that included 1,131
overweight or obese adults and the authors found that those who received chitosan had an
average weight loss of almost 4 pounds more than those on placebo in the short term, and their
cholesterol and blood pressure levels also decreased more than those in the placebo group.
And, they didn't observe any side effects in the group taking chitosan. [2]

WHAT ARE THE SIDE EFFEFCTS OF CHITOSAN?
If chitosan really can  prevent the fat absorption (as indicated in the recent report), it can also
prevent the absorption of other fat-soluble substances (e.g. fat-soluble vitamins and essential
fatty acid) and negative-charged substance (chitosan is positively-charged).

WHAT ARE OTHER POTENTIAL HEALTH BENEFITS OF CHITOSAN?
While almost everybody focuses chitosan application on weight management or obesity
prevention or whatever, two research groups are busy to find more benefits of chitosan:

An Indian research group depolymerized chitosan to obtain water-soluble low-molecular weight
chitosan and chitooligosaccharides. They found that water-soluble low-molecular weight chitosan
and chitooligosaccharides inhibited the growth of Ehrlich ascites tumor cells and tumor-induced
neovascularization. [3] Almost at the same time, a Japanese research group also found the
low-molecular-weight chitosans or oligochitosan might be useful in preventing tumor growth
through the activation of intestinal immune functions. [4]

References

[1] Tharanathan RN et al Chitin--the undisputed biomolecule of great potential. Crit Rev Food Sci Nutr.
2003;43(1):61-87.
[2] Ni Mhurchu C, et al. Chitosan for overweight or obesity. The Cochrane Database of Systematic
Reviews 2005, Issue 3.
[3] Harish Prashanth KV et al, Depolymerized products of chitosan as potent inhibitors of tumor-induced
angiogenesis. Biochim Biophys Acta. 2005 Feb 11;1722(1):22-9. Epub 2004 Dec 15.

[4] Maeda Y et al Antitumor effects of various low-molecular-weight chitosans are due to increased natural
killer activity of intestinal intraepithelial lymphocytes in sarcoma 180-bearing mice. J Nutr. 2004
Apr;134(4):945-50.
Discuss with your doctor before taking any alternative medicine. This article is for