Plasma cholesterol chitosan effects

A number of studies have revealed that chitin and chitosan are effective cholesterol-lowering supplements and fat blockers. When chitosan is used as a food supplement, chitosan can effectively reduce low-density lipoprotein (LDL), cholesterol, and plasma cholesterol while improves the HDL choles-terol/total cholesterol ratio (Koide 1998). These studies indicated that increased bile acid excretion and/or decreased cholesterol absorption was responsible for it (Marlett 1997). 

Chitosan also has hypocholesterolemic effects and acts as an adjuvant to weight loss in rat studies [31,32]. Studies have reported that chitosan reduced the concentration of plasma cholesterol in animals [33,34] and type If diabetes patients in combination with hypercholesterolemia [33]. This property is being attributed to the positive charge of the molecule that binds to fatty acids (released from consumed fat) and bile salt components, which results in disrupted lipid absorption in the gut [5]. Also, chitosan is dissolved in the stomach, emulsifying the fat and forming a gel in the intestine which entraps fat and prevents intestinal absorption [35,36]. Chitosan forms a floccule in the duodenum which entraps dietary oil [37]. However, these effects are still controversial [31,38,39]. Actually, van Bennekum et al. [32] suggested that the incorporation of chitosan in the diet of rats reduces cholesterol (food) intake, but did not affect either intestinal cholesterol absorption or faecal sterol output. 

LeHoux and Grondin (1993) investigated the effects of chitosan on plasma and liver cholesterol levels, liver weight, and 3-hydroxy-3-methylglutaryl coenzyme A reductase in rats fed on a sterol diet (1% cholesterol and 0.2% cholic acid). Chitosan at a level of 5% lowered plasma and liver cholesterol levels by 54% and 64%, respectively. High MW chitosan (>750 kDa) had less hypocholesterolemic potential than that of 70 kDa. 

In vivo studies were also conducted by several researchers. Anraku et al. (2009) examined the antioxidant effects of water-soluble chitosan in normal subjects by measuring the reduction of indices of oxidative stress. Treatment with chitosan for 4weeks produced a significant decrease in levels of plasma glucose and the atherogenic index, and led to an increase in high-density lipoprotein cholesterol (HDL-C). Chitosan treatment also lowered the ratio of oxidized to reduced albumin and increased total plasma antioxidant activity. Further, Anraku et al. (2011) proved the antioxidant effects of high MW chitosan in normal volunteers, and the obtained results were consistent with previous results observed by Anraku et al. (2009). 

Chiang, M. T., Yao, H. T., and Chen, H. C. 2000. Effect of dietary chitosan with different viscosity on plasma lipids and lipid peroxidation in rats fed on a diet enriched with cholesterol. Bioscience Biotechnology and Biochemistry 64 965-971. 

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