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Chitin and Chitosan

What are chitin and chitosan?

Chitin is a non-digestible carbohydrate extracted from the shells of crabs, lobsters, shrimps, Antarctic krills or other crustaceans. It is made of acetylated glucosamine molecules linked by beta-1,4 glycosidic bonds [1].

Chitosan is naturally or synthetically produced by deacetylation of chitin (removing acetyl [COCH3] groups). In the human intestine, chitin and chitosan act as a viscous insoluble fiber [1]. They are partly degraded by normal colonic bacteria into glucosamine [1].

Chitin and Chitosan as Food Additives

Chitin and chitosan can be used as an “added fiber”, thickener, texturizer, emulsifier, humectant, stabilizer in dairy products, baked goods, confectionery, beverages and other commercial foods [1].

Chitosan Supplements

Without prescription or over-the-counter (OTC):

  • Chitin flakes and microcrystalline chitosan in a powder, tablet or capsule form

Suggested Chitosan Supplements Effects, but Insufficient Evidence

  • Chitosan is advertised as a laxative, but constipation is one of the reported chitosan side effects [1].
  • Several human clinical trials have shown negligible effect of chitosan on the intestinal fat absorption and weight loss [2].
  • Various human clinical trials have shown no or insignificant effect of chitosan on blood cholesterol and triglyceride levels [3,4,5].
  • Chitosan may cause a slight reduction of a high blood pressure [1].
  • Studies have shown no significant effect of chitosan on the absorption of calcium or any other mineral [1].

Chitosan Safety: Side Effects, Toxicity

Except mild nausea and constipation, no serious side effects or toxicities of chitosan are known [1]. Chitosan is Generally Recognized As Safe (GRAS) by  the U.S. Food and Drug Administration (FDA) [1]. People allergic to crustaceans should avoid chitin and chitosan [3].

  1. GRAS claim notification: Primex chitosan US Food and Drug Administration
  2. Mhurchu CN et al, 2005, Effect of chitosan on weight loss in overweight and obese individuals: a systematic review of randomized controlled trials  PubMed
  3. Ylitalo R et al, 2002, Cholesterol-lowering properties and safety of chitosan  PubMed
  4. Wuolijoki E et al, 1999, Decrease in serum LDL cholesterol with microcrystalline chitosan  PubMed
  5. Bokura H et al, 2003, Chitosan decreases total cholesterol in women: a randomized, double-blind, placebo-controlled trial  PubMed


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