Health Care Professional Information
Scientific Name
Deacetylated chitin bipolymer
Common Name
Chitosan, kitosan, chitin
Brand Name
Fat Trapper™, Fat Trapper Plus™, Fat Absorb™, Fat Blocker™
Clinical Summary
Chitosan is a derivative of chitin extracted from the exoskeleton of crustaceans, including shrimp, lobster, and clams. It is used as an excipient in pharmaceutical formulations and as a dietary supplement for weight loss, hyperlipidemia, and wound healing. It is also made into an edible film to protect food from spoilage (1). Although marketers of weight loss supplements claim that chitosan can bind with fat in the gut, clinical trials did not find any increase in fecal excretion of fat or weight loss compared to placebo (2) (3) (4).
Chitosan may lower low-density lipoprotein (LDL) cholesterol, although an optimal dose and long-term efficacy are not yet established (5) (6). One small study in obese patients found that chitosan supplementation decreased weight, body mass index (BMI), waist circumference, and triglycerides (TG) (7). A systematic review of the published literature also concluded that chitosan reduces total cholesterol, but larger, randomized controlled trials are necessary to determine its effect on other lipoproteins (8). Chitosan may increase total plasma antioxidant activity and lowered indices of oxidative stress in humans (9). Limited clinical data are available regarding efficacy for anemia or chronic renal failure, although chitosan did show benefit in a small randomized study (10).
Reported adverse events include constipation and gastrointestinal distress (2). Patients allergic to shellfish should not use this supplement.
Purported Uses
- High cholesterol
- Weight loss
- Wound healing
Constituents
- Linear copolymer of β-(1,4)-poly-2-amino-2-deoxy-d-glucose and β-(1,4)-poly-2-acetamido-2-deoxy-d-glucose
(9)
Mechanism of Action
Following oral administration, chitosan forms a positively charged gel matrix in stomach acid able to bind bile acids, nitrogen metabolites, phospholipids, unesterified cholesterol, fat-soluble vitamins, and calcium (5). Increased elimination of fat has not been demonstrated (3). Topical application enhances wound healing by stimulation of granulation tissue. Possible mechanisms of action include formation of a gel-like fibronectin matrix that facilitates inward epithelial cell migration and the formation of heparin-chitosan complexes that ultimately activates growth factors that bind to stabilized heparin (12). In an in vitro study, chitosan demonstrated an antioxidant effect by reducing albumin carobonyls and hydroperoxides in a time dependent manner (9).
Pharmacokinetics
Chitosan is not absorbed systemically.
Warnings
In April 2000, the Federal Trade Commission issued a court order against Enforma Natural Products, Inc., manufacturers of Fat Trapper and Fat Trapper Plus, for making unsubstantiated and deceptive claims about the health benefits of these products. The order prohibits Enforma from using the name “Fat Trapper” and requires them to disclose in advertising that dieting and/or exercise are required to lose weight. FTC report available at: http://www.ftc.gov/opa/2002/07/enforma.htm.
Contraindications
Patients with shellfish allergy should not use chitosan.
Adverse Reactions
Reported: Constipation, flatulence, and GI distress symptoms.
(4) (8)
Literature Summary and Critique
Hernández-González SO, et al. Chitosan improves insulin sensitivity as determined by the euglycemic-hyperinsulinemic clamp technique in obese subjects. Nutr Res. 2010 Jun;30(6):392-5.
The objective of this randomized, double-blind study was to evaluate the effect of chitosan on insulin sensitivity through use of the euglycemic-hyperinsulinemic clamp technique. Twelve obese, nondiabetic patients received chitosan tid before meals for 3 months and the control subjects (n=6) received placebo. Serum glucose, total cholesterol, HDL cholesterol, and triglycerides (TGs) were measured at baseline and at the end of the 3 month study. Chitosan significantly increased insulin sensitivity (2.4 + 1.4 vs 3.6 + 1.4 mg/kg/min, P=.043). There was also a significant decrease in weight (90.7 + 14.2 vs 84.7 + 13.7 kg;P=.027), BMI (34.3 + 2.7 vs 31.6 + 2.2 kg/m2;P=.028), waist circumference (106 + 12 vs 99 + 9 cm;P=0.28) and TGs (2.4 + 0.9 vs 1.6 + 0.9 mmol/L;P=.028) in the group receiving chitosan. No adverse events were observed. The authors concluded that chitosan increased insulin sensitivity and decreased weight, BMI, waist circumference, and TG in obese patients.
Dosage (Inside MSKCC Only)
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References
- Cagri A, Ustunol Z, Ryser ET. Antimicrobial edible films and coatings. J Food Prot. 2004 Apr;67(4):833-48.
- Pittler MH, et al. Randomized, double-blind trial of chitosan for body weight reduction. Eur J Clin Nutr 1999;53:379-81.
- Guerciolini R, et al. Comparative evaluation of fecal fat excretion induced by orlistat and chitosan. Obes Res 2001;9:364-7.
- Pittler MH, Ernst E. Dietary supplements for body-weight reduction: a systematic review. Am J Clin Nutr. 2004 Apr;79(4):529-36.
- Maezaki Y, et al. Hypocholesterolemic effect of chitosan in adult males. Biosci Biotech Biochem 1993;57:1439-44.
- Tai TS, et al. Effect of chitosan on plasma lipoprotein concentrations in type-two diabetic subjects with hypercholesterolemia. Diabetes Care 2000;23:1703-4.
- Hernández-González SO, González-Ortiz M, Martínez-Abundis E, et al. Chitosan improves insulin sensitivity as determined by the euglycemic-hyperinsulinemic clamp technique in obese subjects. Nutr Res. 2010 Jun;30(6):392-5.
- 8. Baker WL, Tercius A, Anglade M, et al. A meta-analysis evaluating the impact of chitosan on serum lipids in hypercholesterolemic patients. Ann Nutr Metab. 2009; 55(4):368-74.
- Anraku M, Fujii T, Furutani N, et al. Antioxidant effects of a dietary supplement: reduction of indices of oxidative stress in normal subjects by water-soluble chitosan. Food Chem Toxicol. 2009 Jan;47(1):104-9.
- Jing SB, et al. Effect of chitosan on renal function in patients with chronic renal failure. J Pharm Pharmacol 1997;49:721-3.
- Koide SS. Chitin - chitosan: properties, benefits, and risks. Nutrition Research 1998;18:1091-101.
- Stone CA, et al. Healing at skin graft donor sites dressed with chitosan. Br J Plast Surg 2000;53:601-6.
Consumer Information
How It Works
Bottom Line: Current evidence is insufficient to support the efficacy of chitosan for weight loss or cholesterol reduction.
The main ingredient in chitosan is chitin, an extract from the shells of sea creatures. Chitin is not absorbed in the human GI tract, and therefore is completely eliminated in the feces. The marketers of chitin-containing weight loss products claim that chitin binds to fat and cholesterol in the intestine, preventing them from being absorbed. However, in an evaluation of people before and after using chitosan, it was found that chitosan did not result in increased levels of fat excreted in their feces. On the downside, chitin may reduce the absorption of other important nutrients, such as nitrogen, vitamins, and calcium. Application of chitosan to wounds has been shown to aid in wound healing; scientists think it may enhance a number of the steps in the formation of new tissue.
Purported Uses
- For weight loss
Insufficient clinical evidence exists to support the use of chitosan alone (without dietary changes or exercise) for weight loss.
- To lower their cholesterol
Some clinical trials support this use, but its long-term effectiveness is unknown.
- To treat anemia associated with chronic kidney failure
One clinical trial supports this use, but more research is needed.
- Topically, for improved wound healing
Laboratory evidence and one clinical trial support this use.
Research Evidence
Insulin sensitivity:
Twelve obese, nondiabetic patients received chitosan three times a day before meals for 3 months and the control subjects received placebo. Serum glucose, total cholesterol, HDL cholesterol, and triglycerides (TGs) were measured at baseline and at the end of the 3 month study. Chitosan significantly increased insulin sensitivity. There was also a significant decrease in weight, BMI , waist circumference and TGs in the group on chitosan.
Patient Warnings
- In April 2000, the Federal Trade Commission issued a court order against Enforma Natural Products, Inc., manufacturers of Fat Trapper® and Fat Trapper Plus®, for making unsubstantiated and deceptive claims about the health benefits of these products. The order prohibits Enforma from using the name “Fat Trapper” and requires them to disclose in advertising that dieting and/or exercise are required to lose weight. FTC report available at: http://www.ftc.gov/opa/2002/07/enforma.htm.
Do Not Take If
- You are pregnant (chitosan decreases intestinal absorption of vitamins A, D, E, K, and calcium, which are important during pregnancy).
- You are allergic to shellfish (chitosan is composed of shellfish exoskeletons).
Side Effects
- Constipation
- Flatulence
- Gastrointestinal distress symptoms (bloating, cramping)
Last updated: November 28, 2012
absorption (ub-SORP-shun)
The process of taking nutrients from the digestive system into the blood so they can be used in the body.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)acid (A-sid)
A chemical that gives off hydrogen ions in water and forms salts by combining with certain metals. Acids have a sour taste and turn certain dyes red. Some acids made by the body, such as gastric acid, can help organs work the way they should. An example of an acid is hydrochloric acid. Acidity is measured on a scale called the pH scale. On this scale, a value of 7 is neutral, and a pH value of less than 7 to 0 shows increasing acidity.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)administration (ad-MIH-nih-STRAY-shun)
In medicine, the act of giving a treatment, such as a drug, to a patient. It can also refer to the way it is given, the dose, or how often it is given.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)albumin
A protein manufactured by the liver.
(http://www.cancer.gov/dictionary)anemia (uh-NEE-mee-uh)
A condition in which the number of red blood cells is below normal.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)antioxidant (AN-tee-OK-sih-dent)
A substance that protects cells from the damage caused by free radicals (unstable molecules made by the process of oxidation during normal metabolism). Free radicals may play a part in cancer, heart disease, stroke, and other diseases of aging. Antioxidants include beta-carotene, lycopene, vitamins A, C, and E, and other natural and manufactured substances.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)baseline (BAYS-line)
An initial measurement that is taken at an early time point to represent a beginning condition, and is used for comparison over time to look for changes. For example, the size of a tumor will be measured before treatment (baseline) and then afterwards to see if the treatment had an effect.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)bile (bile)
A fluid made by the liver and stored in the gallbladder. Bile is excreted into the small intestine, where it helps digest fat.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)BMI
Body mass index. A measure that relates body weight to height. BMI is sometimes used to measure total body fat and whether a person is a healthy weight. Excess body fat is linked to an increased risk of some diseases including heart disease and some cancers. Also called body mass index.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)body mass index (BAH-dee mas IN-dex)
A measure that relates body weight to height. BMI is sometimes used to measure total body fat and whether a person is a healthy weight. Excess body fat is linked to an increased risk of some diseases including heart disease and some cancers. Also called BMI.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)calcium (KAL-see-um)
A mineral needed for healthy teeth, bones, and other body tissues. It is the most common mineral in the body. A deposit of calcium in body tissues, such as breast tissue, may be a sign of disease.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)cell (sel)
The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)chitin (KY-tin)
A type of polysaccharide (sugar molecule) that is made by some plants and animals. The hard outer shell of shrimp, lobsters, and many insects is made of chitin.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)cholesterol (koh-LES-teh-rol)
A waxy, fat-like substance made in the liver, and found in the blood and in all cells of the body. Cholesterol is important for good health and is needed for making cell walls, tissues, hormones, vitamin D, and bile acid. Cholesterol also comes from eating foods taken from animals such as egg yolks, meat, and whole-milk dairy products. Too much cholesterol in the blood may build up in blood vessel walls, block blood flow to tissues and organs, and increase the risk of developing heart disease and stroke.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)chronic (KRAH-nik)
A disease or condition that persists or progresses over a long period of time.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)clinical (KLIH-nih-kul)
Having to do with the examination and treatment of patients.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)clinical trial (KLIH-nih-kul TRY-ul)
A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)constipation (KON-stih-PAY-shun)
A condition in which stool becomes hard, dry, and difficult to pass, and bowel movements don’t happen very often. Other symptoms may include painful bowel movements, and feeling bloated, uncomfortable, and sluggish.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)copolymer (KOH-pah-lih-mer)
A molecule made up of two or more different kinds of small molecules called monomers. The monomers are joined together in a repeating pattern.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)distress (dih-STRESS)
Extreme mental or physical pain or suffering.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)dose (dose)
The amount of medicine taken, or radiation given, at one time.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)efficacy (EH-fih-kuh-see)
Effectiveness. In medicine, the ability of an intervention (for example, a drug or surgery) to produce the desired beneficial effect.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)epithelial (eh-pih-THEE-lee-ul)
Refers to the cells that line the internal and external surfaces of the body.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)extract (EK-strakt)
In medicine, a preparation of a substance obtained from plants, animals, or bacteria and used as a drug or in drugs.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)feces (FEE-seez)
The material in a bowel movement. Feces is made up of undigested food, bacteria, mucus, and cells from the lining of the intestines. Also called stool.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)gastrointestinal (GAS-troh-in-TES-tih-nul)
Refers to the stomach and intestines. Also called GI.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)GI
Refers to the stomach and intestines. Also called gastrointestinal.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)glucose (GLOO-kose)
A type of sugar; the chief source of energy for living organisms.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)heparin (HEH-puh-rin)
A substance that slows the formation of blood clots. Heparin is made by the liver, lungs, and other tissues in the body and can also made in the laboratory. Heparin may be injected into muscle or blood to prevent or break up blood clots. It is a type of anticoagulant.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)in vitro (in VEE-troh)
In the laboratory (outside the body). The opposite of in vivo (in the body).
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)insulin (IN-suh-lin)
A hormone made by the islet cells of the pancreas. Insulin controls the amount of sugar in the blood by moving it into the cells, where it can be used by the body for energy.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)intestinal (in-TES-tih-nul)
Having to do with the intestines.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)intestine (in-TES-tin)
The long, tube-shaped organ in the abdomen that completes the process of digestion. The intestine has two parts, the small intestine and the large intestine. Also called bowel.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)mass (mas)
In medicine, a lump in the body. It may be caused by the abnormal growth of cells, a cyst, hormonal changes, or an immune reaction. A mass may be benign (not cancer) or malignant (cancer).
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)obese (oh-BEES)
Having an abnormally high, unhealthy amount of body fat.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)oral (OR-ul)
By or having to do with the mouth.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)oxidative stress (OK-sih-DAY-tiv ...)
A condition in which antioxidant levels are lower than normal. Antioxidant levels are usually measured in blood plasma.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)placebo (pluh-SEE-boh)
An inactive substance or treatment that looks the same as, and is given the same way as, an active drug or treatment being tested. The effects of the active drug or treatment are compared to the effects of the placebo.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)plasma (PLAZ-muh)
The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)randomized
Describes an experiment or clinical trial in which animal or human subjects are assigned by chance to separate groups that compare different treatments.
(http://www.cancer.gov/dictionary)renal failure (REE-nul FAYL-yer)
A condition in which the kidneys stop working and are not able to remove waste and extra water from the blood or keep body chemicals in balance. Acute or severe renal failure happens suddenly (for example, after an injury) and may be treated and cured. Chronic renal failure develops over many years, may be caused by conditions like high blood pressure or diabetes, and cannot be cured. Chronic renal failure may lead to total and long-lasting renal failure, called end-stage renal disease (ESRD). A person in ESRD needs dialysis (the process of cleaning the blood by passing it through a membrane or filter) or a kidney transplant. Also called kidney failure.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)sensitivity (SEN-sih-TIH-vih-tee)
When referring to a medical test, sensitivity refers to the percentage of people who test positive for a specific disease among a group of people who have the disease. No test has 100% sensitivity because some people who have the disease will test negative for it (false negatives).
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)serum (SEER-um)
The clear liquid part of the blood that remains after blood cells and clotting proteins have been removed.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)significant (sig-NIH-fih-kunt)
In statistics, describes a mathematical measure of difference between groups. The difference is said to be significant if it is greater than what might be expected to happen by chance alone. Also called statistically significant.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)stomach (STUH-muk)
An organ that is part of the digestive system. The stomach helps digest food by mixing it with digestive juices and churning it into a thin liquid.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)supplementation (SUH-pleh-men-TAY-shun)
Adding nutrients to the diet.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)tissue (TIH-shoo)
A group or layer of cells that work together to perform a specific function.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)topical (TAH-pih-kul)
On the surface of the body.
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)wound (woond)
A break in the skin or other body tissues caused by injury or surgical incision (cut).
Source: The National Cancer Institute's Dictionary of Cancer Terms
(http://www.cancer.gov/dictionary)
