Chitosan

Chitosan: What is it?

• Chitosan is a natural polysaccharide derived from chitin which is a widely used biopolymer.

• They are a large component of arthropod shells such as crabs, shrimps, and insects, and are also produced extracellularly by various fungi and algae.

How does it work in the body?

• Studies have shown that Chitosan taken as a food supplement forms a gel in the intestinal tract which binds dietary lipids and other nutrients, resulting in a reduction in intestinal lipid absorption as well as other vitamins and minerals, this in turn causes lower serum cholesterol and triglycerides.

• Chitosan also displays hormonal and protein-modulating properties such as increasing serum leptin concentration and leading to a reduction in C-reactive protein.

What is it used for?

• Chitosan is used as a weight loss and anti-obesity supplement.

• A 2019 meta-analysis showed that Chitosan supplementation led to a clinically significant reduction in body weight, BMI, and body fat.

• Chitosan supplementation is also used as a cholesterol-lowering agent.

• There have also been reports of its use for treating hypertension, wound healing, and for antimicrobial purposes.

• Notably, further studies in human participants are needed to solidify the evidence to support these claims.

Evidence for and against:

• A 2018 meta-analysis showed that Chitosan supplementation can lead to minimal weight loss and an improvement in serum lipid and cardiovascular factors.

• In animal studies, short-term chitosan administration was shown to cause a reduction in the absorption of vitamins and minerals including fat-soluble vitamins, calcium, and Vitamin E. This led to a reduction in bone mineral content and growth restriction [86].

Precautions/side effects:

• Adverse effects of Chitosan include a reduction in Vitamin E levels in plasma, reduction in bone mineral content, growth retardation, and reduced absorption of fat-soluble vitamins and minerals. These may lead to symptoms such as weakness, nausea, diarrhea, constipation, increased bone fragility, and steatorrhea.

  
  

Dosage:

• A meta-analysis which included 14 studies showed a mean dosage of 2 g/day p.o.

Interactions:

• Chitosan has been shown to potentiate the anticoagulant effect of warfarin if used together, likely due to reduced absorption of fat-soluble vitamins, namely Vitamin K.

• Individuals with shellfish allergies should avoid chitosan.

Key Web Sources

• Moraru C, Mincea MM, Frandes M, Timar B, Ostafe V. A meta-analysis on randomised

  controlled clinical trials evaluating the effect of the dietary supplement chitosan on weight

  loss, lipid parameters and blood pressure. Medicina. 2018;54(6):109. https://doi.org/10.3390/

  medicina54060109.

• Koide SS. Chitin-chitosan: properties, benefits and risks. Nutr Res. 1998;18(6):1091–101.,

  ISSN 0271-5317. https://doi.org/10.1016/S0271-5317(98)00091-8.

• Walsh AM, Sweeney T, Bahar B, O’Doherty JV. Multi-functional roles of chitosan as a poten-

  tial protective agent against obesity. PLoS One. 2013;8(1):e53828. https://doi.org/10.1371/

  journal.pone.0053828.

• Huang H, Liao D, Zou Y, Chi H. The effects of chitosan supplementation on body weight

  and body composition: a systematic review and meta-analysis of randomized controlled tri-

  als. Crit Rev Food Sci Nutr. 2020;60(11):1815–25. https://doi.org/10.1080/10408398.201

  9.1602822.

• Huang SS, Sung SH, Chiang CE. Chitosan potentiation of warfarin effect. Ann Pharmacother.

  2007;41(11):1912–4. https://doi.org/10.1345/aph.1K173. Epub 2007 Oct 9.

• Miller K. Chitosan uses and risks. 5 Feb 2021. https://www.webmd.com/vitamins-and-sup-

  plements/chitosan-uses-and-risks. Accessed 1 May 2022.