Chitosan
Per Sloan-Kettering
Uses
- High cholesterol
- Weight loss
- Wound healing
Clinical Summary
Chitosan (KY-to-san) is a derivative of chitin, extracted from the exoskeleton of crustaceans, including shrimp, lobster, and clams, and from the cell wall of Reishi mushrooms. Chitosan is used as an excipient in pharmaceutical formulations and in biomedical applications including wound dressings. It is also made into an edible film to protect food from spoilage. Chitosan is marketed as an all-natural marine fiber for weight loss management and to manage cholesterol.
Animal models suggest antiobesity properties with chitosan and derivative products . In one animal study, a combination of capsaicin and chitosan increased this activity.
Findings from human studies are conflicting. Although marketers of weight loss supplements claim that chitosan can bind with fat in the intestine, some clinical trials did not find any increase in fecal excretion of fat or weight loss compared with placebo. Other studies have had more positive results in combination with additional products or interventions. In a double-blind randomized controlled trial (RCT), polyglucosamine, a low molecular weight chitosan, along with a low-calorie diet and increased exercise for at least 6 months yielded additional weight loss compared with placebo and the same diet/lifestyle changes. Chitosan in combination with L-ascorbic acid produced some effects on bodyweight in overweight women, but there were no significant differences in fat mass, percentage body fat, body circumference, or skinfold thickness compared with placebo control. One single-blind RCT of fungal chitosan found significant bodyweight reductions and improved hemoglobin A1c, body composition, and anthropometric parameters in overweight/obese adults without diet restriction compared with placebo after 3 months. Howevever, due to heterogeneity of studies and mixed results, more trials are needed before definitive conclusions can be drawn.
In diabetic patients, chitosan reduced low-density lipoprotein (LDL) cholesterol and decreased weight, body mass index (BMI), waist circumference, and triglycerides. A systematic review also concluded that chitosan reduces total cholesterol, but larger RCTs are necessary to determine its effect on other lipoproteins.
Chitosan may increase total plasma antioxidant activity and lower the indices of oxidative stress in humans. Limited clinical data are available regarding efficacy for anemia or chronic renal failure, although chitosan did show benefit in a small randomized study.
Reported adverse events include constipation and gastrointestinal distress. Patients allergic to shellfish or mushrooms should use related supplements with caution.
Mechanism of Action
Chitosan is a natural polysaccharide that consists of glucosamine and N-acetylglucosamine copolymers. It has been described as biodegradable, nontoxic, non-immunogenic, and biocompatible, with properties similar to cellulose.
In an in vitro study, chitosan demonstrated antioxidant effects by reducing albumin carobonyls and hydroperoxides in a time-dependent manner.
In animal models, antiobesity effects may occur through serum leptin and C-reactive protein modulation or 5’ adenosine monophosphate-activated protein kinase (AMPK) activation and lipogenesis-associated gene inhibition. In porcine models, chitosan altered genes influencing appetite and feeding behavior in the small intestine (NPY), adipose tissue (Leptin), and the brain (HCRT, INSR, NMB, GHR, PPARG, NPY5R). It also downregulated FABP2gene expression, increased serum leptin, and significantly altered gut microbial populations. In high-fat diet-induced obese rodents, chitosan oligosaccharides improved dyslipidemia and prevented body weight gain by inhibiting adipocyte differentiation. As an insoluble fiber, low molecular weight chitosan polyglucosamines can bind to fat in the intestinal lumen, forming a complex that is partially utilized by colon bacteria and partially eliminated, but appropriate concentrations are needed. In one of these animal studies, it was suggested that the more likely mechanisms for weight loss could include bacterial energy wasting, as increased acetate and glucose excretion were also present, suggesting that larger amounts of lipids and glucose were available as fuel for bacteria in the colon.
Hypocholesterolemic effects from chitosan in murine models were not due to reduced cholesterol absorption efficiency or increases in fecal sterol output, so that a major bile acid-binding capacity was ruled out. The more likely scenario is that the fiber’s influence on satiation and satiety reduces food intake suppression and therefore cholesterol.
Human studies suggest that it is unlikely that chitosan binds fat in intestines, and could therefore not support this purported mechanism of action.
Topical application enhances wound healing by stimulation of granulation tissue. Possible mechanisms include formation of a gel-like fibronectin matrix that facilitates inward epithelial cell migration and the formation of heparin-chitosan complexes that activate growth factors that bind to stabilized heparin.
Studies
Isolation of chitosan from Ganoderma lucidum mushroom for biomedical applications.
Chitosan oligosaccharide attenuates hepatic steatosis in HepG2 cells via the activation of AMP-activated protein kinase. Chitosan oligosaccharides (COSs), oligomers of decomposed chitosan possess many biological functions including immunomodulatory, antitumor, and antiinflammation. The aim of this study was to investigate the protective effects of COS against free fatty acid (FFA)-induced cellular hepatic steatosis
Antimicrobial
Antimicrobial edible films and coatings.
Antioxidant
Cholesterol
A meta-analysis evaluating the impact of chitosan on serum lipids in hypercholesterolemic patients.
Obesity/Overweight
- Effect of a polyglucosamine on the body weight of male rats: Mechanisms of action. .
- Activity of two different polyglucosamines, L112 and FF45, on body weight in male rats.
- Chitosan supplementation and fecal fat excretion in men.
- Randomized, double-blind trial of chitosan for body weight reduction
- Comparative evaluation of fecal fat excretion induced by orlistat and chitosan.
- Dietary supplements for body-weight reduction: a systematic review
- Chitosan improves insulin sensitivity as determined by the euglycemic-hyperinsulinemic clamp technique in obese subjects.
- Multi-functional roles of chitosan as a potential protective agent against obesity.
- Prawn Shell Chitosan Has Anti-Obesogenic Properties, Influencing Both Nutrient Digestibility and Microbial Populations in a Pig Model.
- Prawn Shell Chitosan Exhibits Anti-Obesogenic Potential through Alterations to Appetite, Affecting Feeding Behaviour and Satiety Signals In Vivo.
- Preventive effects of chitosan coacervate whey protein on body composition and immunometabolic aspect in obese mice.
- Anti-obese effect of glucosamine and chitosan oligosaccharide in high-fat diet-induced obese rats.
- Antiobese effects of capsaicin-chitosan microsphere (CCMS) in obese rats induced by high fat diet.
- Efficacy of polyglucosamine for weight loss-confirmed in a randomized double-blind, placebo-controlled clinical investigation.
- Single-blind, placebo controlled randomised clinical study of chitosan for body weight reduction.
- L-ascorbic acid addition to chitosan reduces body weight in overweight women.
- The effect of the dietary supplement, Chitosan, on body weight: a randomised controlled trial in 250 overweight and obese adults.
Renoprotective
Effect of chitosan on renal function in patients with chronic renal failure