In a study involving 21 overweight subjects with normal cholesterol levels, 2.4 g of a supplement containing chitosan and glucomannan (1.2 g each) were administered daily for 28 days. Subjects were advised to maintain their normal dietary and activity patterns throughout the study; and it was confirmed in the blood work that caloric intake and intake of fat and dietary fiber (excluding the supplement) did not alter between the beginning and end of the study. At the end of the study, serum total, HDL, and LDL levels were reduced significantly compared with the initial period; however, serum triacylglycerol concentration did not change. Fecal fat excretion did not change between the two periods, but there was a trend toward excretion of neutral sterols and bile acids. Owing to this finding, the authors concluded that the cholesterol lowering properties of chitosan and glucomannan are probably the result of the increase in fecal steroid excretion and not to fat excretion (Gallaher et al., 2002).

Maezaki et al. (1993) found that 3-6 g/day of chitosan reduced total serum cholesterol in eight healthy males and increased HDL levels. The average decrease in LDL was from 189 mg/dL before treatment to 177 mg/dL after 14 days of treatment (three 1-g chitosan biscuits daily for 7 days, and six 1-g biscuits daily for 7 days). Once the supplementation of the biscuits was stopped, the total cholesterol levels increased again to a level not significantly different from the starting value. The serum HDL cholesterol levels increased significantly from 51 mg/dL to 56 significant reductions in body weight (9.26% C and 3.60% P), over-weight percentage (11.26% C and 4.14% P), total cholesterol (23.37% C and 10.87% P), LDL cholesterol (27.09% C and 10.94% P), and triglycerides (21.16% C and 11.40% P) in both groups. HDL cholesterol levels increased 13.44% in the C group and 2.27% in the P group. Additionally, to find out whether chitosan was interfering with the absorption of mineral salts or fat-soluble vitamins, blood concentrations of sodium, potassium, calcium, magnesium, zinc, iron, copper, and vitamins A, D, and E were measured and found to have no significant changes between the two groups. Only mild and transient effects were found in both groups, with 5% reporting flatulence in the C group and 18.4% reporting nausea and/or constipation in the P group, with no statistically significant differences between the two groups (Colombo and Sciutto, 1996).

Macchi (1996) studied the effect of a chitosan fiber product (Somagril) plus a low-calorie diet or free diet in 30 obese subjects for the period of 1 month in a randomized, placebo-controlled study. The chitosan group (C) was treated with 4 tablets/day combined with a 1,200-calorie diet, the placebo group (P) was treated with the same low-calorie diet with 4 tablets/day of a placebo, and a third group (F) had no dietary restrictions plus the chitosan treatment. Reductions were found in body weight (4 kg C, 2.6 kg P, and 2.8 kg F); body mass index (1.7 kg/cm2 C, 0.6 kg/cm2 P, and 1.1 kg/cm2 F); body fat (4% C, 1.2% P, and 3.3% F); and skin folds (17 mm C, 5 mm P, and 11 mm F). It is interesting to note the greater reduction in skin folds in both the chitosan groups versus the placebo. The author pointed out that even if the body weight reductions in the placebo and chitosan groups were similar, the groups with the chitosan treatment, with or without the dietary restrictions, produced a greater loss of adipose tissue as reflected by the skin fold data. Diastolic blood pressure was significantly decreased in the C (7 mm Hg) and F (9 mm Hg) groups but not in the P group (1 mm Hg). In all groups, plasma cholesterol and triglyceride levels decreased, but only in the F group was there an increase in HDL. The author noted no significant adverse effects.

In a randomized, double-blind, placebo-controlled study of 90 obese people, the effect of a chitosan fiber along with a low-calorie diet was measured on weight loss and lipid-lowering parameters. The chitosan fiber product (Somagril) studied was given at a dosage of 4 tablets/ day (unspecified amount of chitosan). The chitosan group (C) and the placebo group (P) followed a low-calorie diet, and both showed reduction in body weight (7.19 kg C and 3.36 kg P) at the end of the study, with a statistically greater effect found in the chitosan group. Statistically significant reductions in overweight percentage (10.4% C and 3.8% P), arterial systolic (12.1 mm Hg C and 2.8 mm Hg P) and diastolic pressure (12.4 mm Hg C and 3.8 mm Hg P), total cholesterol (25.3% C and 11.1% P), LDL cholesterol (32.1% C and 13.6% P), and triglycerides (22.6% C and 10.1% P) were found. The C group showed a statistically mg/dL after treatment with chitosan; likewise, when the treatment was stopped, levels decreased to similar pretreatment levels.

Additionally, it was found that the excretion of primary bile acids, cholic acid, and chenodeoxycholic acid were significantly increased by chitosan treatment, whereas the excretion of cholic acid was decreased after treatment stopped. The authors concluded that these findings suggest the mechanism for reducing cholesterol is a reduction of the cholesterol “pool” in the body through the combination and elimination of chitosan with bile acids in the digestive tract. The dosage recommendations of chitosan supplements are about 2-6 g/day, in divided 1-g doses with each meal.

Much work has been performed to determine the possible toxicity of chitosan because of its use as a pharmaceutical drug delivery adjunct, and it has been found to be quite safe. However, because it has the ability to absorb fats, it may also absorb fat-soluble vitamins and carotenoids when supplemented at high dosages. Additionally, chitosan may cause gas, bloating, and diarrhea owing to the blockage of fat digestion (Deuchi et al., 1995; Ylitalo et al., 2002).

A warning may be found on many labels of chitosan supplements against use by people with shellfish allergies. However, because chitosan is made from the shells (versus the protein-containing meat) of shellfish, opinion is mixed as to whether someone with a severe allergy could experience problems.

Author Bio: Georgiy Kharchenko with American Weight Loss Group LLC: Fitness Trainer, Ephedra Products, Natural Weight Loss Pills, Phentramin D Tablets

Category: Medicines and Remedies
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