Biomedical Engineering Reference
In-Depth Information
6.9
Chitosan as Lipid Lowering Agent & Dietary
Supplement in Aid of Weight Loss
Unlike inactive cellulose, chitin and chitosan, as dietary i bers, exhibit
hypolipidemic activity. h is is coni rmed by the reduced cholesterol and
triglyceride levels in serum and liver of rats, in a 4 week study in animals
kept on diet of 1 % cholesterol + 0.1 % bile salts containing 4 % chito-
san [239]. Chitosan was much more ef ective than chitin. A similar trend
was observed by other investigators as well [240]. Chitosan has also been
shown to reduce plasma cholesterol in cholesterol-fed broiler chickens at
dietary concentrations of 1.5-3.0 % [241, 242]. Sugano,
et al.
, studied the
relationship between hypocholesterolemic ei cacy and average molecular
weight of chitosan in rats fed on cholesterol-enriched diet [243]. At a 5
% dietary level, chitosan almost completely prevented the rise of serum
cholesterol level. However, at a 2 % level, chitosan, with viscosity at both
the extremes, exerted a comparable cholesterol lowering action. h us, the
hypocholesterolemic action of chitosan was proposed to be independent of
its molecular weight.
Ef ect of various dif erent grades of chitosan on faecal excretion of fat in
rats fed on a high fat diet was investigated by Deuchi,
et al
[244]. Chitosan
intake resulted in a higher level of fat being excreted by rats receiving corn
oil than those receiving lard, although the ef ect was strong for both diet
groups. A supplement of ascorbic acid to each chitosan diet resulted in a
signii cant depression of fat digestion and absorption in the lumen. It was
observed that an increase in the viscosity or the degree of deacetylation of
chitosan resulted in a pronounced ef ect on the apparent digestibility of
fats. Ormrod,
et al.
, studied ef ect of chitosan in apolipoprotein E-dei cient
mice which had hypercholesterolemia, rapid development of atheroscle-
rosis and the lesions histologically similar to those seen in humans was
observed [245]. Mice were fed for 20 weeks on a diet containing 5 % chi-
tosan or on a control diet. Blood cholesterol levels were found to be sig-
nii cantly lower in chitosan treated mice, and at 20 weeks, were 64 % of
control levels. On comparing the aortic plaque in the two groups, a highly
signii cant inhibition of atherogenesis in both the whole aorta (42 %) and
the aortic arch (50 %) was observed in the chitosan fed mice, suggesting
the possible use of chitosan in inhibiting the development of atheroscle-
rosis in individuals with hypercholesterolemia. Kanauchi,
et al.
, attributed
chitosan's ability to inhibit fat digestion to its dissolution in the acidic envi-
ronment of the stomach, with a subsequent change to a gel form capable
of entrapping fats and oils in the intestine [246, 247]. A synergistic ef ect
