Chitosan is a substance made from the shells of various types of shellfish, including shrimp and crab. While chitosan is sometimes used in plastic surgery to encourage tissue growth and encourage wound healing and by dentists to treat gum disease, it is perhaps best known as a dietary supplement. While scientific studies proving its efficacy are lacking, many consumers use chitosan to treat conditions such as obesity and high cholesterol. Chitosan is available over the counter, without a doctor's prescription. Common chitosan side effects include stomach upset, constipation, and gas. Other potential problems with the consumption of chitosan are possible drug interactions, triggering of a shellfish allergy, and malabsorption of some nutrients.
Chitosan is often consumed before a meal with the hope that it will absorb dietary fat, thus preventing the digestion of the fat and its calories. While its efficacy as a weight-loss treatment has not been proven, many people continue to buy and use chitosan for that purpose. Some users complain of the most common chitosan side effects such as gastric upset and gas, though the distress is usually not severe and goes away after awhile.
The more serious concerns about chitosan side effects involve its ability to to bind with fat, which may interfere with the absorption of essential minerals, fat-soluble vitamins, and certain drugs. Pregnant women in particular are cautioned against the use of chitosan as it may keep them from properly absorbing such essential nutrients as vitamins A and D as well as calcium. Certain drugs, such as oral contraceptive pills, are likewise fat-soluble, and they may be rendered less effective by the consumption of chitosan. There is also evidence that chitosan increases the effects of warfarin, a blood thinner. Because this interaction could result in increased bruising or bleeding, warfarin users should avoid chitosan.
Even though they are technically not chitosan side effects, allergic reactions remain a concern for potential users of chitosan. Medical writers are careful to note that shellfish allergies are triggered by the meat of a shellfish, not its shell. It is still a good idea for those who suffer from shellfish allergies to be wary of chitosan and to be on the lookout for symptoms of a shellfish reaction. These symptoms can include swelling, skin rash, and breathing problems. Because these symptoms can be severe, and even deadly, chitosan users who experience these symptoms should seek medical attention at once.
