The most widely promoted health benefit of chitosan is to boost fat loss. Supplement makers often claim that chitosan binds to fat in the body and allows you to excrete more of it, thereby reducing the amount of fat your body stores.
Chitosan blocks the absorption of dietary fat. This potent dietary supplement binds with fat and prevents it from depositing and accumulating in the body. This action prevents weight gain, making the body appear slimmer. The absorbed fat and cholesterol is excreted together with the stools during bowel movement. The United States Food and Drug Administration considers Chitosan as possibly safe for consumers.
Chitin is a biodegradable fiber most commonly derived from the outer shells of shrimp and other shellfish. It is also found in the skeletons of insects and fungi. Some even call chitin “nature’s armor” due to its extreme resilience and robustness .
Chitosan is a processed form of chitin. Chitin is made up of hardy and highly insoluble chains of N-acetylglucosamine. Chitosan, on the other hand, is more soluble is mostly made up of glucosamine chains [2, 3].
The production chitosan starts with the selection of suitable source for chitin extraction. Chitin can be extracted from either the animal sources such as shellfish or the non-animal sources such as fungi. The physicochemical properties of chitosan can vary greatly depending on its source.
Chitin is extracted from the natural sources via demineralization and deproteination. The purified Chitin is then treated with concentrated alkalis (e.g. sodium hydroxide) to obtain Chitosan.
For a report published in the Cochrane Database of Systematic Reviews in 2008, researchers reviewed 15 clinical trials (with a total of 1,219 participants) that tested the effects of chitosan on adults who were overweight or obese. Compared to participants given a placebo, study members treated with chitosan appeared to lose significantly more weight and experience beneficial changes in cholesterol levels and blood pressure. However, the report’s authors note that many of the reviewed trials were of poor quality. Furthermore, findings from the high-quality trials suggest that chitosan may have a minimal, insignificant effect on weight.
A meta-analysis of five small Italian trials was performed in 1998; the mean difference in weight reduction between chitosan and placebo was 3.28 kg (7.2 lb), but methodological problems were identified.5
Chitosan alone cannot be recommended as a weight loss agent. More study is needed to determine its role in the management of lipid disorders. As it appears safe, a trial for cholesterol lowering can be considered, perhaps for low-risk patients who are near their LDL goal. Because of its source, chitosan cannot be recommended for people who have an allergy to shellfish.
A review of studies published in a 2008 issue of the “Cochrane Database of Systematic Reviews” evaluated the effectiveness of chitosan for health benefits in overweight and obese people. The 15 studies included 1,219 participants. On average, chitosan intake led to significant weight loss, reduced total cholesterol and decreased blood pressure as compared with placebo. The authors cautioned that when they narrowed the studies to those of higher quality with larger numbers of participants and longer duration, the improvements were much smaller.
Research appearing in the June 1999 issue of “Methods and Findings in Experimental and Clinical Pharmacology” found that otherwise healthy obese women taking chitosan supplements did not experience significant decreases in cholesterol or triglyceride levels when compared to women taking a placebo. In fact, the group taking chitosan experienced slightly increased triglycerides. Neither group lost weight. The women taking chitosan consumed three 400mg capsules twice per day for eight weeks.
In a small study, 12 healthy men and 12 healthy women (BMI 20–36) followed the same diet for 12 days (five meals per day with 38% of energy from fat) . Chitosan capsules taken before meals (total of 2.5 g/day) slightly increased fecal fat excretion in the men compared to the control group. However, the amount of fat that the chitosan trapped would result in a loss of only 1 lb body fat over about 7 months. Chitosan had no significant effect on fecal fat excretion in the women compared to the control group.The authors of a Cochrane review that included 13 trials examining the effect of chitosan on body weight found that chitosan, when taken for 4 weeks to 6 months, reduced body weight by a mean of 1.7 kg compared with placebo . They concluded that chitosan appears to be more effective than placebo for short-term weight loss, but most studies have been of poor quality. The authors also noted that results from high-quality trials indicate that chitosan has minimal effects on body weight, and these effects are probably clinically insignificant.
Chitosan is used to treat obesity, high cholesterol, and Crohn’s disease. It is also used to treat caused by dialysis in patients with kidney failure, including high cholesterol, “tired blood” (anemia), loss of strength and appetite, high phosphorous levels (hyperphosphatemia), and trouble sleeping (insomnia).
Some people apply chitosan directly to their gums to treat inflammation that can lead to tooth loss (periodontitis), or chew gum that contains chitosan to prevent “cavities” (dental caries).
In an effort to help “donor tissue” rebuild itself, plastic surgeons sometimes apply chitosan directly to places from which they have taken tissue to be used elsewhere.
One study noted chitosan significantly reduced the creatinine in rats that had kidney failure.
Chitosan supplements may be a good choice for people looking to reduce their creatinine levels naturally, but it is always best to discuss the right options with a doctor before taking any supplement.
There is conflicting evidence about the effectiveness of chitosan for lowering cholesterol. Some research shows that taking chitosan does not seem to significantly decrease total cholesterol or “bad” low-density lipoprotein (LDL) in people with high cholesterol. However, other research shows that chitosan seems to lower cholesterol in people with or without high cholesterol. Also, some combination products containing chitosan also seem to reduce cholesterol levels in obese people with or without high cholesterol. Those combination products include: a supplement containing chitosan, garcinia, and chromium and another supplement containing chitosan, guar meal, ascorbic acid, and other micronutrients.
And a somewhat less expected, but curious use:
A Scottish company is developing a biodegradable food wrapping using waste material from shellfish.
Cuantec is extracting a natural substance called chitin from shells after processing langoustines.
The chitin is turned into a more soluble product, chitosan, for the manufacture of a clear film.
Cuantec says its process for extracting chitin uses less chemicals and is more environmentally friendly than conventional methods.
While still in development, a major supermarket chain is already interested in using it for packaging fish.
Chitosan is POSSIBLY SAFE for most people when taken by mouth for up to 6 months or when applied to the skin for a short time. When taken by mouth, chitosan might cause mild stomach upset, constipation, or gas.
Special Precautions & Warnings:
Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking chitosan by mouth if you are pregnant or breast-feeding. Stay on the safe side and avoid use.
Shellfish allergy: Chitosan is taken from the outer skeleton of shellfish. There is a concern that people with allergies to shellfish might also be allergic to chitosan. However, people who are allergic to shellfish are allergic to the meat, not the shell. So some experts believe that chitosan may not be a problem for people with shellfish allergy.
The adverse effects of chitosan are minor and primarily involve the gastrointestinal tract. They include flatulence, bloating, mild nausea, constipation, indigestion, and heartburn [93,95,96]. Because chitosan is derived from shellfish, people who are allergic to shellfish could theoretically be allergic to chitosan .
Chitosan oral supplements are usually made from shellfish-derived powder packed into veggie caps. Dosages range from ~700 mg per serving to 1,800 mg per serving.
Some companies sell chitosan as a liquid oral spray, pressed tablets or loose powder (you can even pack it into veggie capsules yourself).
All these are sold as either chitin, chitosan, chitosan oligosaccharide, or their combination. Chitosan oligosaccharide is more soluble than chitin or chitosan .
The standard dosage of chitosan is 3 to 6 g per day, to be taken with food.
Chitosan can deplete the body of certain minerals (see Safety Issues below). For this reason, when using chitosan, it may be helpful to take supplemental calcium , vitamin D , selenium , magnesium , and other minerals.
Also, according to a preliminary study in rats, taking vitamin C along with chitosan might provide additional benefit in lowering cholesterol.