Chitosan is a fibrous material extracted from the shells of crustaceans such as shrimp and lobsters. This material has a number of uses, ranging from medical care to industrial water treatment. Manufacturers of chitosan sell the product in several different formats which are designed for various uses. The development of a range of uses for this product demonstrates a creative approach to what was once waste material; seafood processors can sell shells of crustaceans, rather than discarding them as garbage.
In agriculture, chitosan has been shown to be beneficial for plants. It strengthens the natural defenses of plants to help them resist fungi and pests, and it also appears to enhance growth by promoting photosynthesis. Several gardening products which are intended to boost plant health contain this compound, and researchers have even taken chitosan into space for agricultural experiments. It is also used in self-healing polyurethane products.
From a health perspective, chitosan is interesting because it has the capability to attract sediments and particles, and it can also absorb compounds from its surrounding environment. It is used in water processing and treatment to remove impurities, including heavy metal, with the compound being scattered on the water, allowed to attract sediment, and then skimmed away to pull the impurities out. Water treatment plants all over the world utilize chitosan for this purpose, taking advantage of the fact that it is a natural and nontoxic compound.
Chitosan has also been shown to be effective in promoting clotting. Wound dressings permeated with this compound are used in some hospital environments to promote rapid clotting. Since the compound is not associated with toxicity or dangerous side effects, it can be used in a wide variety of patients with a high degree of safety. However, chitosan can be dangerous for people with shellfish allergies, because it contains proteins found in shellfish and the body may react to those proteins.
Some health food stores market chitosan supplements as weight loss aids. According to the claims made by manufacturers of these products, chitosan binds to fat in the body, making fat difficult to absorb and allowing it to pass through the body. While this is true, a single pill can only remove an estimated 10 calories from the body, making it not terribly useful for weight loss; people would be better off making small adjustments to their diets to reduce caloric intake, or adding more exercise to burn more calories.