Chitin (pronounced KITE-in): a nitrogen-containing polysaccharide, related chemically to cellulose, that forms a semitransparent horny substance and is a principal constituent of the exoskeleton or outer covering of insects, crustaceans and arachnids - Random House Unabridged Dictionary
Chitin is not exactly a household word, but most are familiar with its source. It is found naturally in the shells of crustaceans, such as crab, shrimp and lobster, as well as in the exoskeleton of marine zoo-plankton, including coral and jellyfish. Insects, such as butterflies and ladybugs, have chitin in their wings. And the cell walls of yeast, mushrooms and other fungi also contain this natural substance.
Chitin and its derivatives have many properties that make them attractive for a wide variety of applications, from food, nutrition and cosmetics to biomedicine, agriculture and the environment. Their antibacterial, anti-fungal and anti-viral properties make them particularly useful for biomedical applications, such as wound dressings, surgical sutures and as aids in cataract surgery and periodontal disease treatment. Research has shown that chitin and chitosan are non-toxic and non-allergenic, so the body is not likely to reject these compounds as foreign invaders. Chitin's biodegradable and anti-fungal properties are a plus for environmental and agricultural uses.
Chitin is one of the three most abundant polysaccharides in nature, in addition to cellulose and starch. It ranks second to cellulose as the most plentiful organic compound on earth. Cellulose and starch are key carbohydrates which plants use as a food source and to build cell walls. In addition, they have widespread use in the industry. Researchers and entrepreneurs see similar potential for chitin.
Chemically, cellulose, starch and chitin are polysaccharides -- polymers, or large molecules consisting of smaller sugar molecules strung together, like pearls on a strand. Chitin can be processed into many derivatives, the most readily available being chitosan, which is formed when chitin is heated with a chemical solution.
Oligosaccharides are among the most popular functional food components in Japan, but they are relatively unknown in the U.S. A number of health benefits result from ingestion of oligosaccharides, according to an article in the October 1994 issue of Food Technology. According to the article, oligosaccharides may increase the production of Bifidobacteria and thereby reduce harmful bacteria, help reduce toxins and detrimental enzymes, prevent diarrhea and constipation, protect liver function, reduce serum cholesterol, protect against cancer and help produce nutrients.
Unlike most polysaccharides, chitosan has a strong positive charge which allows it to bind to negatively charged surfaces such as hair and skin. This makes it useful as an ingredient in skin and hair care products. Several studies indicate that chitosan's charge also helps it bind to fats and cholesterol and initiate clotting of red blood cells.
Over the past decade, researchers in Korea, Japan, Europe and the United States have tested chitin and its derivatives in biomedical applications. Researchers also have focused on the food and nutrition arenas, including edible films and coatings to preserve the quality and texture of foods.
Dr. Sam Hudson, associate professor of polymer chemistry at North Carolina (NC) State University, an academic center engaged in significant chitin research, says researchers are "on the edge of a brave new world" as far as the number of products that can be made from chitin and its derivatives.
Studies have suggested that chitin and chitosan have a number of health benefits, including the ability to promote the growth of Bifidobacteria, healthy intestinal bacteria that help ward off disease. Chitin derivatives such as chitin oligosaccharides and chitosan oligosaccharides (smaller components of the chitin and chitosan molecules) also are believed to have many important health dividends, including promotion of bowel health, anti-tumor properties and promotion of these same beneficial Bifidobacteria.
of Chitosan Oligosaccharides and Bifidobacteria
Since the early 1950s, Bifidobacteria have been recognized for their important role in promoting human health. Researchers believe that Bifidobacteria prevent and counteract harmful bacteria, such as E. coli and Salmonella, by producing acetic and lactic acids that suppress the growth of these microbes and by producing antibacterial compounds. They also are thought to aid in the production of B vitamins and folic acid.
Some researchers believe that bifidobacteria have anti-cancer properties, which may be due to immunity enhancement by the cells, cell wall components and extracellular components of Bifidobacteria, according to the Food Technology article.
Clinical and laboratory studies have suggested that a deficiency in Bifidobacteria may induce aging, decrease immunity and contribute to adult disease, including cancer and arthritis. While adding live Bifidobacteria to the food supply would result in health benefits, researchers point out that they would not survive many food-processing techniques. Instead, nominal amounts of oligosaccharides can be added to the diet directly, as a supplement or in food, to promote the growth of these friendly bacteria.
and Weight-Loss Effects
As an added benefit, the study also found that chitosan relieved the lactose intolerance caused by feeds containing whey, a cheese by-product containing 70 percent lactose, says Dr. John Zikakis, professor emeritus of the University of Delaware, who performed much of the research on chitosan-fed chickens. Normally, whey has limited use in animal feed, since it can lead to diarrhea. But chickens fed a substantial level of whey and chitin did not develop diarrhea, he notes. It is thought that this same effect may be achieved in humans.
Research also has shown that general bowel function and regularity improve with the use of dietary chitosan. In animal studies, when gerbils were fed diets supplemented with chitosan, the animals became healthier, with improved vigor. Other experiments demonstrated that when chitosan was added to bread and then fed to gerbils, the same health benefits resulted. Similar benefits have been reported with chitinous supplements in cattle feed.
Researchers speculate that improved regularity also would result in humans who ingest modest amounts of chitosan.
Chitosan also has been shown to have antacid and anti-ulcer activity in rats and dogs. It is believed that chitosan has physical and chemical properties that are similar to the natural substances which coat the gastric tract.
"Chitosan and chitosan oligosaccharide are ideal biomaterials which hold much promise for the future," notes Prodex's Joseph Nichols. "There has been increased interest by scientists worldwide and industry is beginning to recognize their possibilities. They could very well be important biomaterials in the next decade. The day has come for these natural polymers to come into their own."
by Dr. Nobuhide Hoashi
(Atlanta, Georgia: International Commission on Natural Health Products)
(Alpharetta, Georgia: Seaborne, Inc., 1997, 770.663.6633.
Return to Top of the page
Last updated July 17, 1998
Maintained by Dalwoo Corporation