Chitosan

Chitosan- a weight reducing supplement

Reduce weight now! Ask me how? Among all other diet reducing remedies, Chitosan is also considered to be good supplement that helps greatly to reduce excess weight from the body. 

Chitosan (pronounced KITE-o-san) is made of the indigestible chitin of shellfish. The supplement binds with undigested fat as it moves through our intestines before our body has the chance to absorb the fat. Both human and animal studies (including several acknowledged by reputable sources such as the Mayo clinic) show that chitosan can lower both weight and cholesteol levels.
But the Chitosan supplement usually has some side-effects including extreme stomach ache due to

1. Failure to absorb vitamins A, D, E, and K that are fat-soluble vitamins.
2. Possible decrease in calcium absorption
3. Decrease of certain necessary bacteria in the intestinal track
4. Could affect certain medications that require fat absorption to be effective
5. Dehydration combined with chitosan can cause constipation and bowel obstruction
It gives extremely good results if you will start doing some exercise or walking along with chitosan. Also reduce your diet intake or just reduce carbohydrate or fat intake, you will get extremely beneficial results.
Chitosan may work for some people with a primary concern of the excessive calories they are getting from fat in their diet. Assess why you have this weight to lose before taking any dietary aid. You doctor can help you analyze your diet and exercise habits as well as map out a weight loss strategy that will be healthy for you.

Chitosan is a polysaccharide compound that is found in the shells of sea crustaceans. While chitosan is not digestible it appears to reduce the absorption of bile acids and cholesterol, whereby lowering levels of blood cholesterol. Chitosan's ability to lower blood cholesterol has been shown in animals and a few human studies showed that about 5 grams a day of chitosan taken for a few weeks was able to produce a 6% drop in cholesterol.

There is some preliminary evidence that supplemental chitosan may have beneficial effects on lipids and be useful for those suffering from renal failure. There is also evidence to support that chitosan might even help to prevent atherosclerosis and could play a role in wound healing, some types of diabetes and liver disease. While it has been suggested that chitosan may help to reduce weight, prevent cancer, heal ulcers, aid digestion and help the immune system these claims have not be substantiated by any scientific findings.

Chitosan is available in several supplemental forms. When using chitosan to lower cholesterol 1000 to 2000 milligrams twice a day is a typical dosage. Make sure to check purity of any chitosan supplement you intend to take as many chitosan supplements may be contaminated with lead, mercury, iron, copper and arsenic.

Never take chitosan within two hours of taking vitamins A, D, E and K, flavonoids, carotenoids or prescription drugs.

PURPOSE

The purpose of this backgrounder is to present a summary of current scientific data and research regarding the use of chitosan as a dietary supplement.

INTRODUCTION

Chitosan is a derivative of chitin, a polysaccharide that is the major component of the shells of crustaceans and insects. Chitin consists of long chains of acetylated D-glucosamine, that is, glucosamine with acetyl groups on the amino groups (N-acetylglucosamine). Chitosan is N-deacetylated chitin, although the deacetylation in most chitosan preparations is not complete. Chitin itself is usually prepared from crab or shrimp shells or fungal mycelia. Treatment with an alkali then produces chitosan with about 70% deacetylation. Chitosan preparations can vary in molecular weight, ranging from 100,000 to 500,000 MWU (1A). Chitosan is not digestible by mammalian digestive enzymes (2A).

Both chitin and chitosan are highly basic (alkaline) polysaccharides and act as polycationic polymers- they possess multiple positive charges. Chitosan's properties enable it to be formed into fibers and films, used to chelate metal ions, and used in a number of industrial and medical applications, including drug delivery systems and wound healing (1A). This backgrounder will only consider chitosan's effects on lipids, body weight and blood pressure.

BIOLOGICAL EFFECTS

Chitosan ingestion lowers plasma cholesterol levels in several animal models (2). Clinical studies in humans have given mixed results on its ability to lower cholesterol and triglyceride levels, reduce body weight and lower blood pressure. A variety of chitosan preparations have been used in these studies.

In a 4 week randomized, double-blind, placebo controlled study a mixture of chitosan, Garcinia cambogia and chromium was given to groups of 50 obese subjects who were maintained on a low calorie diet. Significant effects compared to placebo were seen in subjects given 240 or 480 mg chitosan per day, with total cholesterol reduced 20-29%, LDL-cholesterol reduced 23-35%, triglycerides reduced 18-27%, HDL-cholesterol increased 9-14% and reduction in obesity calculated at 8-12% (3A).

Several randomized, double-blind, placebo controlled clinical trials have been performed using a mixture of chitosan, guar (a legume), ascorbic acid and "other micronutrients" (4A, 5A, 6A,7A). The specific composition of this mixture is not stated in these reports. These studies utilized a total of 221 obese subjects consuming low calorie diets and ingesting daily 4 tablets of the chitosan preparation. In each of these trials the experimental groups showed significant differences with the placebo groups in total, LDL- and HDL-cholesterol, weight reduction and blood pressure. The placebo groups showed significant differences with baseline levels of these parameters. All of these studies indicated a low incidence of minor side effects of chitosan use; one study (7A) reported no interference with absorption of minerals and fat soluble vitamins.

Preparations containing chitosan as the only active agent have also been used in human studies. In a small open trial with 8 healthy adult Japanese males on a conventional diet, ingesting daily 3 g chitosan for 7 days followed by 6 g /d for the next 7 days, total cholesterol was reported to be decreased and HDL-cholesterol increased (8A). A randomized, double-blind, placebo controlled trial with 33 Type 2 hypercholesterolemic diabetic subjects, consuming their normal diets, used 1.35 g of chitosan or placebo in 3 doses per day for 8 weeks followed by a crossover for the next 8 weeks. Significant lowering of total and LDL-cholesterol occurred in the chitosan group; no significant differences were seen in triglycerides or HDL-cholesterol (9A). In another randomized, double-blind, placebo controlled clinical trial of chitosan for weight loss, 59 mildly obese women received 3 g of a rapidly-soluble chitosan preparation (>90% chitosan, <10% succinic acid) or placebo in 2 doses per day, while consuming their regular caloric intake. After 8 weeks a statistically significant reduction in weight was seen in the chitosan group. The placebo group exhibited a significant weight gain- the authors state that the study was conducted during the November-December period (10A).

Other workers have not found a weight loss effect with chitosan use in the absence of a hypocaloric diet. In one randomized, double-blind, placebo controlled study 30 overweight subjects consumed 0.6 g of chitosan twice a day for 28 days while maintaining their usual eating patterns. No significant differences were seen in weight, blood pressure, blood lipids or blood fat-soluble vitamin levels (11A). A similar result was reported in a double-blind, placebo controlled Finnish study in which 51 obese women were given 1.2 g of chitosan or placebo twice daily for 8 weeks while eating their routine diets. No reduction in weight was noted; in a subgroup of more obese subjects LDL-cholesterol was reduced (12A).

A meta-analysis of 5 studies that used the chitosan-guar mixture concluded that in conjunction with a hypocaloric diet, chitosan use produced a greater weight loss than placebo. The authors stated their concern over lack of a specific formula for this preparation, lack of citation of any of these studies in conventional databases (the reports were provided by a manufacturer), and the need for further independent research (13A). A review of weight-loss products concluded that there was no proof of efficacy in humans for chitosan use in the absence of a hypocaloric diet, and that further good quality research was required (14A).

The mechanisms of chitosan's biological effects have not been clearly defined. Its weak anion exchange activity and the high viscosity of its solutions may explain decreased cholesterol absorption and increased excretion of bile acids following chitosan ingestion. An animal study suggested that viscosity is not a factor in chitosan activity and cited other work showing that chitosan activity may depend on lipase inhibition and/or formation of fat and cholesterol micelles which pass through the intestine unabsorbed (2A). Other workers question that the reported weight losses on hypocaloric diets can be due to increased fat excretion, since these diets do not contain enough fat to explain the weight loss; they suggest that other mechanisms, such as appetite suppression, be considered (13A).

The different results reported for chitosan use may be due to variations in the chitosan preparations, including adjuvants or excipients used, molecular weight and degree of deacetylation, and different dosages and times of administration in relation to meals (10A).

SAFETY

The human studies with chitosan have reported only mild adverse effects, similar to those seen in the placebo groups. No long-term studies of human safety have been reported. Short-term (2 week) human use of chitosan was reported to produce a change in fecal microbiota and composition, possibly of a beneficial nature (15A).

NOTICE

By furnishing this backgrounder, NNFA does not provide any opinion as to:
" The safety of any product containing this ingredient;
" The efficacy of any product containing this ingredient;
" The use of any specific brand of product; or
" The level of substantiation for either the safety or efficacy of any such product.
Neither this backgrounder nor any portion of this backgrounder may be used in advertising or promotional materials. In addition, this backgrounder does not constitute, and is not to be used as, "third party literature" as that term is used in connection with section 5 of the Dietary Supplement Health and Education Act (DSHEA).

As with any health-related product, consumers should discuss the use of any products with a health care practitioner.

REFERENCES*

1A. Kumar, MNV A review of chitin and chitosan applications. Reactive & Functional Polymers 46, 1-27 (2000)

2A. Gallaher, CM et al. Cholesterol reduction by glucomannan and chitosan is mediated by changes in cholesterol absorption and bile acid and fat excretion in rats. J Nutr 130, 2753-59 (2000)

3A. Girola, M et al. Dose effect in lipid-lowering activity of a new dietary integrator (chitosan, Garcinia cambogia extract and chrome). Acta Toxicol Ther XVII, 25-40 (1996)

4A. Sciutto, AM & P Colombo. Lipid-lowering effect of chitosan dietary integrator and hypocaloric diet in obese subjects. Acta Toxicol Ther XVI, 215-230 (1995)

5A. Veneroni, G et al. Effect of a new chitosan integrator and hypocaloric diet on hyperlipidemia and overweight in obese patients. Acta Toxicol Ther XVII, 53-70 (1996)

6A. Giustina, A & P Ventura. Weight-reducing regimens in obese subjects: effects of a new dietary fiber integrator. Acta Toxicol Ther XVI, 199-214 (1995)

7A. Colombo, P & AM Sciutto. Nutritional aspects of chitosan employment in hypocaloric diet. Acta Toxicol Ther XVII, 287-302 (1996)

8A. Maezaki, Y et al. Hypocholesterolemic effect of chitosan in adult males. Biosci Biotech Biochem 57, 1439-44 (1993)

9A. Tai, T-S et al. Effect of chitosan on plasma lipoprotein concentrations in Type 2 diabetic subjects with hypercholesterolemia. Diabetes Care 23, 1703-4 (2000)

10A. Schiller, RN et al. A randomized, double-blind, placebo-controlled study examining the effects of a rapidly soluble chitosan dietary supplement on weight loss and body composition in overweight and mildly obese individuals. J Am Nutraceut Assn 4, 34-41 (2001)

11A. Pittler, MH et al. Randomized, double-blind trial of chitosan for body weight reduction. Eur J Clin Nutr 53, 379-81 (1999)

12A. Wuolijoki, E et al. Decrease in serum LDL cholesterol with microcrystalline chitosan. Methods Find Exp Clin Pharmacol 21, 357-61 (1999)

13A. Ernst, E & MH Pittler. Chitosan as a treatment for body weight reduction? A meta-analysis. Perfusion 11, 461-5 (1998)

14A. Egger, G et al. The effectiveness of popular, non-prescription weight loss supplements. Med J Aust 171, 604-8 (1999)

15A. Terada, A et al. Effect of dietary chitosan on faecal microbiota and faecal metabolites of humans. Microb Ecol Health Dis 8, 15-21 (1995)

*KEY TO REFERENCE HIERARCHY
A reference: research article or editorial comment in peer-reviewed journal

B reference: letters to the editor, professional personal communications, meeting/conference abstracts (NOT usually peer reviewed), and pending reviewed publications

C reference: lay/trade press publications, interviews, patents and Web site material (NOT peer-reviewed)