Chitosan for Weight Loss and Cholesterol Management

Kelly M. Shields, Pharm.D., Nick Smock, Pharm.D., Cydney E. McQueen, Pharm.D., Patrick J. Bryant, Pharm.D., FSCIP


Am J Health Syst Pharm. 2003;60(13) 

In This Article

Clinical Studies

In a randomized, double-blind, placebo-controlled trial in 34 volunteers, Pittler et al.[10] assessed chitosan for weight reduction in the absence of other dietary alterations. Participants ranged from 18 to 60 years of age, and body mass indices (BMIs) ranged from 23.9 to 29.9 kg/m2. The subjects were randomized to receive either four 250-mg chitosan capsules or four placebo capsules twice daily for 28 days. Assessment of body weight, blood pressure, quality of life, cholesterol levels, and serum vitamin levels occurred at baseline, 14 days, and 28 days. Four participants withdrew from the trial (reasons not given), so the calculated statistical power of 80% was not met. The researchers found no significant differences between groups in any outcome measures except serum vitamin K concentration, which was higher (0.56 ng/mL versus 0.33 ng/mL) in the chitosan group. No serious adverse effects were reported for either group. A poststudy analysis of the chitosan preparation used showed that the capsules contained only 42% of the labeled amount of chitosan.

A second trial in 69 mildly obese women (BMI, 27-40 kg/m2) compared chitosan with placebo for weight loss in the absence of other lifestyle modifications over an eight-week period.[11] Participants received either three 500-mg capsules of rapidly dissolving chitosan (LipoSan Ultra, Vanson Inc.) or placebo twice daily. Calorie and dietary fat intake were assessed, as well as body weight, BMI, waist-to-hip ratio, and fecal fat excretion. Ten patients, most of whom were noncompliant, dropped out of the study. At the completion of the study, mean weight had decreased 1 kg in the treatment group and increased 1.5 kg in the placebo group (p < 0.005); BMI decreased significantly in the treatment group. A small, nonsignificant increase in fecal fat elimination occurred in the treatment group. Adverse effects in the treatment group included gastrointestinal discomfort, flatulence, and stool bulkiness.

A trial of chitosan in seven healthy males assessed fat absorption, as measured by fecal fat excretion.[12] Participants were placed on a diet containing more than 120 g of fat per day for 12 days; during the treatment phase (days 6-9), the participants also received 5.25 g of chitosan daily. Fecal samples were collected daily on days 2 through 12. There was no significant difference in mean ± S.D. fecal fat excretion between the placebo and treatment periods (6.0 ± 1.0 versus 6.8 ± 0.4 g/day), nor were there significant differences in fecal mass or body weight. No adverse reactions to chitosan were reported.

Guerciolini et al.[13] compared chitosan and orlistat to determine their effect on fat absorption. Twelve healthy volunteers (within 20% of their ideal body weight) participated in this 14-day open-label crossover study consisting of a one-week run-in period, one week of treatment with orlistat 120 mg three times daily, and one week of treatment with chitosan 445 mg three times daily. The participants consumed standardized diets of 2500 kcal/day throughout the trial, and fecal samples were collected during the run-in and treatment periods. Orlistat produced a significant increase in mean ± S.D. fat excretion from baseline (1.36 ± 0.45 g/day versus 16.13 ± 7.27 g/day). However, chitosan had no significant effect on fat excretion (1.36 ± 0.45 g/day versus 0.27 ± 1.02 g/day). The chitosan recipients noted fewer gastrointestinal adverse effects (8%) than the orlistat group (66%) (p not reported).

A randomized, double-blind, placebo-controlled trial in 100 mildly obese adults on a hypocaloric diet (1000 kcal/day) was performed to evaluate the impact of chitosan on body weight and blood pressure.[14] Patients received two tablets of chitosan (amount unspecified) or placebo twice daily for four weeks. Significant reductions were seen in all outcome measures in both groups. A greater reduction in mean body weight was seen in the chitosan group (from 83.6 kg to 76.3 kg) than in the placebo group (from 82.3 kg to 79.3 kg). The only adverse effect reported was occasional mild nausea in two participants in each group.

Wuolijoki et al.[15] undertook a randomized, double-blind, placebo-controlled trial to evaluate the impact of chitosan on serum LDL-cholesterol levels in the absence of any changes in eating or lifestyle. Fifty-three healthy women were given either 1200 mg of microcrystallized chitosan or placebo twice daily for eight weeks. Outcome measures included total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, and body weight. No significant changes were noted in any outcome measure. However, there was a significant difference in LDL-cholesterol reduction among a subgroup with a BMI of >30 kg/m2 at the end of the fourth week.

A pilot study assessed the effect of chitosan on cholesterol levels in eight healthy men between 20 and 23 years of age.[16] After a three-day placebo period, the participants received three biscuits daily, each containing chitosan 1 g, for seven days, followed by six biscuits per day for seven days and three days of placebo biscuits. Outcome measures included total cholesterol, serum HDL cholesterol, triglycerides, and fecal bile-acid secretion. Mean total serum cholesterol decreased from 189 to 177 mg/dL (p < 0.01) during the period of chitosan ingestion; this change was reversed during the final three days of placebo ingestion. Serum HDL cholesterol increased from 51 to 56 mg/dL (p < 0.05) during chitosan treatment, and this was reversed when chitosan was discontinued. There were no significant changes in the other outcome measures.

In a double-blind study in 88 subjects, Ho et al.[17] assessed the impact of chitosan on both weight loss and cholesterol management. Participants were obese (defined as >20% body fat for males and >30% body fat for females) and hypercholesterolemic (total cholesterol concentration, >5.20 mmol/L). After a 4-week placebo run-in period, the subjects were randomly assigned to placebo capsules or capsules containing 257 mg of shellfish chitosan (Absorbitol, MinusFat Ocean Healthcare Pte, Ltd.) and instructed to take four capsules three times daily for 12 weeks. BMI, blood pressure, percent body fat, and lipid profiles were obtained at each of the three visits. There were no significant changes from baseline in any outcome measures in either group.

Three randomized, placebo-controlled, double-blind trials were performed to evaluate the impact of chitosan on cholesterol and weight loss.[18,19,20] These trials each included 80-90 mildly obese adults. All participants were placed on a hypocaloric diet (1000 kcal/day) and two tablets containing chitosan (amount unspecified) twice daily for four weeks. Primary outcome measures included body weight, percent overweight, total cholesterol, triglycerides, HDL cholesterol, and LDL cholesterol. All participants had significant improvements in all primary outcome measures. Mean weight reduction in the chitosan groups ranged from 7.19 to 8.17 kg, while total cholesterol reduction ranged from 23.3% to 25.3%. All therapies were well tolerated; the most common adverse effect was mild and transient nausea.

A trial in 30 obese subjects (25% over ideal body weight) was designed to compare the effect of chitosan with the usual diet and chitosan with a hypocaloric diet on weight and cholesterol reduction.[21] The double-blind study randomized subjects to a diet of 1200 kcal/day and 1 g of chitosan before each meal, 1200 kcal/ day and a placebo tablet before each meal, or the patient's usual diet and 1 g of chitosan before each meal. At the completion of the four-week trial, a significant reduction in body weight was noted in all three groups. There was a significant reduction in total cholesterol in both chitosan groups, and triglycerides decreased in all subjects on the hypocaloric diet. The only adverse effect was constipation in two participants.


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