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CHITOSAN FOR BODY WEIGHT MANAGEMENT
Mikio Kato, MD, FACS, FACOG Gene Mazzocco, MD, FACP Edward O. Dingilian, PE
Obesity and diabetes are major causes of morbidity and mortality in United States.1More than 100 million
Americans are overweight, and more than 25 million are obese according to the U.S. Centers for Disease Control and Prevention (CDC). Since 1980 juvenile obesity has doubled in United States. Obesity is growing
faster with African American, Hispanic and American Indian women.
An accepted scale of obesity is the body mass index (BMI), calculated as weight in kilograms divided by the square of the height in meter. The medical field defines overweight as a BMI from 25 to 29.9, and that obesity is set at a BMI of 30 and over.
Besides antiobesity prescription drugs,2 consumers have access to a variety of dietary supplements that may show with certain individuals some degree of body weight loss under specific conditions, one such product is chitosan. Overweight and obese individuals report from no loss to significant weight loss after using chitosan.
Carbohydrate, protein, and fat nutrients in food are the source of body energy calories. A certain amount of fat is required for normal physiological functions. Energy needs are to sustain body basal metabolism, plus daily physical activities. Body weight is a function of energy balance between the amount of food intake and energy expenditure, irrespective of the energy source. Body preference is to break down carbohydrates to glucose for energy prior to fats. Unspent glucose is synthesized to triglycerides, which is a form of fat. Fat is denser and has over twice as much calories than carbohydrate.
Glucose converted to triglycerides, plus unused portion of dietary fat converted to triglycerides in the stomach are stored in body tissue for future use to balance energy needs during food deprivation. Sustained accumulation of stored fat gradually bulges, and over time becomes apparent in the abdominal area, thighs, legs, and arms. During food deprivation the body draws the needed amount of calories from stored fat, causing weight loss.
Calorie intake, expenditure and storage is affected by numerous other biological and behavior factors like race, gender, age, metabolic and endocrine factors, genetics, smoking, physical activity levels, nutrition, and socioeconomic circumstances.3,4 With advancing age body metabolism decreases, hence food intake should diminish to avoid weight gain.5
A survey conducted by the National Center for Health Statistics showed the average American diet contained 34% of total calories from fat compared to Government recommendation of 30% or less. American average daily calorie intake at all ages is increasing, while physical activities are diminishing as a result of socioeconomic changes. This development is also observed in other industrialized nations.
Recent surveys indicate American consumers are abandoning low-fat foods, and opting to fat filled foods for more flavor, taste, and satiety. The body digests fat slower than carbohydrate and protein, the reason fat foods give the feel of fullness and satisfaction. Eating fast allows more food intake before satiety. Just five years ago, nearly one in three new food products made a low-fat claim. Today, only one in ten mention low fat.
Obesity is the prime suspect to diseases like osteoarthritis,6 type-2 diabetes which accounts for 90-95 percent of all diabetes cases,7 coronary atherosclerosis,8 renal cancer9 and more. With increased longevity, and without changes of present lifestyle, obesity as a disease may have severe implications in the near future on the general population, health providers and our national economy.
Chitosan is the generic name of a large family of long chain biopolymers derived from natural chitin found in the shell of shrimp, crab and lobster. The active ingredient in chitosan is glucosamine which has unique properties when used as dietary supplement. Chitosan dissolves in stomach acid , becomes electrically charged, thereby binding to opposite charge particles like digested fat, and precipitates together with the bound fat in an alkaline medium representative of the small intestine.
In-vitro, affinity of chitosan to bind fats, oils, and grease is well documented in scientific literature.10 This affinity is strongly affected by the type of chitosan, its purity, ionic strength, reactivity, concentration, and solubility, which indicates that results will substantially vary depending on the chitosan used for the test. In the absence of chitosan standards for dietary supplement applications, this may be a partial explanation consumers are experiencing different results. It is recommended to purchase chitosan supplements from established manufacturers who can back their products with verifiable certificates of analysis.
Based upon laboratory demonstrated fat binding affinity of chitosan, the dietary supplement market extended the same hypothesis with the intent to bind, and partially or totally eliminate dietary fat from the gastro-intestinal tract prior it being absorbed by the body. The actual fat binding mechanism by chitosan in the gastro-intestinal tract in the presence of other nutrients, enzymes, electrolytes, body metabolism is complex and presently little understood.
Based upon human and animal tests, it is postulated chitosan dissolves in the stomach to form an emulsion which binds with digested fats, and precipitates in the alkaline part of the small intestine. A great portion of these bound fats are excreted in the feces rather than absorbed. Animal tests show chitosan might also inhibit intestinal absorption of dietary fat by inhibiting hydrolysis of the fat by pancreatic enzyme lipase.11 Chitosan appears to be devoid of side effects in daily doses averaging 1500mg-2500mg, however not recommended for those with shellfish allergies.
Human tests conducted for short periods with limited groups using chitosan and reduced calorie intake showed statistically significant weight loss according to the researchers.12A randomized, double blind, placebo-controlled trial with overweight and mildly obese individuals conducted over eight weeks indicates a chitosan of specific chemistry taken at a daily dosage may be an effective weight loss dietary supplement, and may prove beneficial for weight maintenance with some individuals.13
The pharmaceutical company Hoffman-La Roche Inc., NJ was recently awarded a U.S patent to coat with a specific chitosan their weight loss drug tablets Orlistat. The company claims effect of the chitosan coating is to strongly reduce the anal leakage of dietary oil.14 Chitosan has no effect on body stored fat, or dietary sugars.
For certain overweight or mildly obese individuals with hypercaloric diet high in fat, chitosan of specific chemistry, purity and dosage combined with physical exercise on sustained basis may be helpful to manage their body weight.15 Pregnant, lactating women, are recommended not to use chitosan. Individuals of 14 years of age or less, persons on medication are asked to consult their physician prior to using chitosan.
Body weight is best managed by consuming a balanced diet of the daily calorie needs, ample water intake, and physical exercise. This regimen requires motivation and self discipline. Such good health practices, in addition to weight control can also extend life.
1. Mokdad AH et al: Epidemics of obesity and diabetes in the United States. JAMA 2001; 286: 1195-1200
2. Hauner H: Current pharmacological approaches to the treatment of obesity. J of Int Obesity 2001; 25: S102-S106
3. Serdula MK et al: Prevalence of attempting weight loss and strategies for controlling weight. JAMA 1999; 282: 1353-1358
4. Hebebrand J et al: The genetics of obesity. J of Int Obesity 2001; 25: S10-S18
5. Hollingsworth P: Food priorities for aging America. Food Technology 1999, 53: 38-68
6. Felson DT et al: Obesity and knee osteoarthritis. The Farmingham study, Ann Intern Med 1988; 109: 18-24
7. HU FB et al: Diet lifestyle, and the risk of Type 2 diabetes mellitus in women. N Engl J Med 2001; 345: 790-797
8. Kortelainen ML et al: Coronary atherosclerosis associated with body structure and obesity in 599 women aged between 15 and 50 years.
Int J of Obesity 1999; 23: 838-844
9. Chow WH et al: Obesity, hypertension, and the risk of kidney cancer in men. N Engl J Med 2000; 343: 1305-1311
10. Nauss JL et al: The binding of micellar lipids to chitosan.
Lipids 1983; 18: 714-719
11. Han LK et al: Reduction in fat storage during chitin-chitosan treatment in mice fat high-fat diet. Int J Obesity 1999; 23: 174-179
12. Colombo P et al: Nutritional aspects of chitosan employment in hypocaloric diet. Acta Toxicol. Ther. 1996; 26: 287-302
13. Schiller RN et al: A randomized, double-blind, placebo-controlled study examining effects of a rapidly soluble chitosan dietary supplement on weight loss and body composition in overweight and mildly obese individuals. J of Amer Nutraceutical Assoc 2001; 4: 34-41
14. US Patent 6030953, Pharmaceutical composition containing chitosan. 2/2001
15. Muzzarelli RA: Chitin and Chitinases 1999; 293-303
Mikio Kato, MD, FACS, FACOG, Gene Mazzocco, MD, FACP,
Edward O. Dingilian, PE, President, United Chitotechnologies, Inc. USA
Correspondence to: Edward O. Dingilian, PE, (e-mail:Edingilian@aol.com)
November 29, 2001