REVIEW

  CHITOSAN, OBESITY EPIDEMIC AND  BODY WELLNESS

  Mikio Kato, MD, FACS, FACOG    Gene Mazzocco, MD, FACP Edward O.Dingilian, PE

Obesity is an ageless nutritional disorder that has no present medical cure except containment. Although some dietary supplements, including chitosan have shown promising results in small-scale studies in humans or animals, there are insufficient long-term clinical data to provide evidence of either safety or efficacy of any of these supplements as agents promoting weight loss.¹ Since overweight and obesity has substantially increased within the last 20 years, a time that the human gene pool has not changed, interest has been aroused on the importance of dietary and physical patterns.² Behavioral interventions to improve diet and increased physical activity are considered the primary means to promote and maintain weight loss and healthy lifestyle.¹

Obesity has increased by more than 50% among adults between 1991-1999. Childhood obesity has reached epidemic proportions; worldwide, approximately 22 million children under five years of age are overweight. Since 1976 the number of overweight children in United States has more than doubled.³ Sharpest observed increases are among boys, African-Americans and Hispanics. More than 100 million Americans are overweight, and more than 25 million are obese according to the U.S. Centers for Disease Control and Prevention.

Latin America is undergoing a rapid demographic and nutritional transition. There is a progressive rise in overweight and obesity, especially in low income groups who improve their income and buy high fat/ high carbohydrate energy dense foods to the detriment of grains, fruits and vegetables.⁴

Data from 1997 China Health and Nutrition Surveys show the shifts in diet and activity are consistent with rapid changes in child and adult obesity, in particular associated with increased income. The quantity of fat in diets increased significantly, and now appears to increase much more rapidly with increased income as Chinese economy continues its expansion.⁵

Carbohydrate, protein, and fat nutrients in food are the source of body energy calories. Energy needs are to sustain basal metabolism, plus daily physical activities. Irrespective of energy source, body weight is a function of energy balance between the amount of food intake and energy expenditure. Human genetic survival is adapted to store excess food to be used during food deprivation. In the absence of food deprivation, the body converts, and stores the excess food in the abdominal area, thighs, legs, and arms leading gradually to overweight and eventually to obesity.

The body’s capacity to change carbohydrate and protein stores is extremely limited, thus energy balance is essentially fat balance.⁶ There is quite a strong evidence that just altering dietary fatty acid profile could substantially alter rate of weight gain and body fat accumulation.⁶ Recent surveys indicate American consumers are abandoning low-fat foods, and opting to fat filled foods for more flavor, taste, and satiety. Fat foods give the feel of fullness and satisfaction. Television viewing has been cited as contributing factor to higher energy or fat intake, often associated with snacking.⁷

Obesity is the prime suspect to diseases like osteoarthritis, type-2 diabetes mellitus which accounts for 90-95 present of all diabetes cases,⁸ coronary arteriosclerosis, renal cancer and more. With increased longevity, and without changes of present lifestyles, obesity as a disease may have severe implications in the near future on the world population, health providers and the worldwide economies.

Many studies demonstrate that obese adults can lose about 0.5 kg per week by decreasing their daily intake to 500 kcal to 1000 kcal below the calorie intake required for the maintenance of their current weight. More severe calorie restrictions, with the use of diets that are low in calories, increases the rapidity of weight loss but not the rate of long-term success in maintaining a reduced weight.¹

Anti-obesity prescription medications currently approved for weight loss in the United States fall into two broad categories: those that decrease food intake by reducing appetite or increasing satiety (appetite suppressants), and those that decrease nutrient absorption called statins. The only FDA-approved medication for obesity that reduces nutrient absorption is orlistat (Xenical). Side effects of orlistat include flatulence with discharge, fecal urgency, fecal incontinence, oily spotting, and increased frequency of defecation.¹ The safety and efficacy of weight loss medications beyond two years of use have not been established. In addition, although some risk factors for obesity related disease are improved with the use of weight-loss medications, the long-term effect of such medications on morbidity and mortality has not been determined.¹

Overweight and obese individuals have also access to a variety of dietary supplements that may show with certain individuals some degree of body weight loss under specific conditions.

Popular weight loss dietary supplements include ephedrine which has appetite suppressant properties. Case reports concerning ephedra alkaloids (often in combination with caffeine) have noted serious cardiovascular and central nervous system events, including hypertension, cardiac arrhythermia, stroke, seizure, myochardial infarction, and sudden death. ⁹ Another dietary supplement product currently sold for weight management is chitosan. Overweight and obese individuals report from no loss to significant weight loss after using chitosan.

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 charges, thereby binding to opposite charged particles like digested fat, and then precipitates together with bound fat in the 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

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 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 intestine. A great portion of these bound fats are excreted in the feces rather than being absorbed. Animal tests show chitosan might also inhibit intestinal absorption of dietary fat by inhibiting hydrolysis of fat by the pancreatic enzyme lipase.¹⁰ Chitosan appears to be devoid of side effects in daily doses averaging 1500 mg-2500 mg . The absence of chitosan standards for dietary supplement applications may be a partial explanation consumers are experiencing varying results. It is recommended to purchase chitosan supplements from established manufacturers who can back their products with verifiable certificates of analysis.

For certain overweight or mildly obese individuals with hypercaloric diet in fat, chitosan of specific chemistry, purity and dosage combined with physical exercise on sustained basis may be helpful to manage their body weight. Individuals with shellfish allergies, 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. Individuals using chitosan for weight management should supplement their daily diet with oil soluble vitamins A, D, E, K.

Moderating calorie intake, limiting saturated fats, increasing intake of soluble fiber, fresh fruits, vegetables, physical activity coupled with reduced stress are still the best proven choices for sustained body weight management.

 

1.   Yanovski SZ et al:  Obesity. N Engl J Med, 2002; vol 346: 591-602
2.    Chen JD. Evolutionary Aspects of Exercise World Rev Nutr Diet , 1999; vol 84: 106-117
3.    Rocchini AP:  Childhood Obesity. N Engl J Med, 2002; vol 346: 854-855
4.   Uauy R et al:  Obesity Trends in Latin America. J Nutr 2001; vol 131: 893S-899S
5.   Popkin BM:  The Nutrition Transition and Obesity in Developing World. J Nutr, 2001; vol 131: 871S-873S
6.   Strolien LH et al:  Dietary Fat Substypes and Obesity World Rev Nutr Diet, 2001; Vol 88: 148-154
7.   French SA et al:  Fast Food Restaurant Use Among adolescent. Int J of Obesity, 2001; 25: 1823-1833
8.   Hu FB et al:  Diet Lifestyle, and The Risk of Type 2 Diabetes Mellitus in Women.N Engl J Med, 2001; vol 345: 790-797
9.    Haller CA et al:  Adverse cardiovascular and central nervous system events associated with dietary supplements containing ephedra alkaloids. N Engl J Med 2000; vol 343: 1833-1838    
10.  Nauss et al:  The Binding of Micellar Lipids to Chitosan. Lipids 1983; 714-719
11.  Han LK et al:  Reduction in Fat Storage During Chitin-Chitosan Treatment in Mice Fed High-Fat Diet. Int J Obesity 1999; vol 23: 174-179

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)

March 18, 2002