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MECHANISMS OF CHITOSAN FAT- BINDING   
Date:
June 25, 2005 08:02 PM
MECHANISMS OF CHITOSAN FAT- BINDING The exact way(s) that Chitosan prevents fat absorbtion is not fully understood but a number of experimental observations support two basic mechanisms. The first mechanism involves the attraction of opposite charges which can be compared to the attraction of opposite magnetic poles. The second entrapment mechanism can be compared to the effect of a net. In the first mechanism the positive charges on chitosan attract the negatively charged fatty acids and bile acids binding them to the indigestible chitosan fiber. This mechanism can explain why chitosan reduces LDL cholesterol levels. Our bodies make bile acids in the liver using the cholesterol from LDL. When chitosan binds bile acids it increases the rate of LDL loss thus improving the LDL to HDL ratio. If enough bile acids are bound, the fats are not solublized, which prevents their digestion and absorption. The second mechanism (figure 2) describes a netting effect of chitosan fiber. In this model the Chitosan wraps around fat droplets and prevents their being attacked and digested by lipid enzymes. Fats unprotected by Chitosan are digested and absorbed. The “netting” mechanism has been seen to operate in vivo. 108 Substances that Enhance the Action of Chitosan Fibers can be likened to a tangled-up chain. Fibers must “unravel” in order for them to be of maximum benefit to us. “Unraveling” is especially critical for chitosan because each link has a hook on which to attach lipids. Chitosan can absorb an average of 4 to 5 times its weight in lipids. Reports of numbers above and below this range have also been reported and may well reflect the rate or extent of unraveling that had taken place. Fiber formulations can be prepared that unravel rapidly and swell quickly. These highly effective formulations are called superAbsorbants. When certain substances are added to chitosan, its remarkable fat-binding ability can be significantly enhanced. Ascorbic Acid D-Ascorbic acid (erythorbic acid) and L-ascorbic acid are C-vitamins which enhance chitosan’s ability to bind lipids. Combining chitosan with ascorbic acid results in even less fat absorption and greater fecal fat losses.77,108 In one study the addition of ascorbic acid to a chitosan enriched diet increased fecal fat losses by 87 percent and decreased fat absorption by over 50 percent.77 Cholesterol oxides cause lesions in artery walls which predispose blood vessels to collect plaque. These dietary cholesterol oxides profoundly influence the initiation of heart disease.Free radicals can also contribute to the formation of cholesterol oxides which are even more likely to damage the heart. Cholesterol oxides have been found in deep-fried foods, powdered eggs, processed meats and in human blood itself. Consequently, taking antioxidants like ascorbic acid is vital to protect against the cellular damage this type of free radical causes.112 Citric Acid In feeding experiments with animals, adding citric acid to a chitosan enriched diet resulted in a decreased feed consumption.77 The most likely explanation for this effect is that the citric acid may be enhancing the swelling action of chitosan leading to a sense of fullness, producing satiety and appetite suppression. Indoles Indoles are remarkable phytochemicals which have the ability to selectively activate certain Mixed Function Oxidases (MFOs).113 These MFO’s help balance estrogen metabolism and prepare dietary toxins for elimination before they are absorbed. The presence of fiber in the intestines provides a bulk agent to carry the metabolized toxins out of the body. Chelat ed Minerals The very best approach to weight loss is to nutritionally augment food choices with nutrient supplementation. Certain biochemical compounds are essential to promoting vigor during the process of thermogenesis. Chelated minerals act to bolster, support and protect the organ systems of the body.114,115 For example, when fat is burned, heat and energy are released. If a lack of certain minerals exists, energy levels will drop. Minerals help to transport needed nutrients to depleted areas of the body, thereby stemming off the fatigue we so often experience after eating a fatty meal. Even more importantly, free radicals are released whenever fat is consumed and burned and the presence of chelated minerals helps to expedite the removal of these metabolites and facilitate the availability of fuel for energy. Essential Fatty Acids Prostaglandins control and balance many body functions. The dietary building blocks for making prostaglandins are the essential fatty acids (EFAs). The role of prostaglandins in weight loss has been extensively discussed in a recent review.116 EFAs exert profound lipid-lowering effects.They reduce the synthesis of triglycerides and very low density lipoproteins (bad cholesterol) in the liver. EFA supplementation coupled with a low-cholesterol, low-saturated fat in diet produces a complementary effect in lowering serum lipid levels.117 Garcinia Cambogia ( Hydroxy Cit ric Acid) Garcinia Cambogia contains hydroxycitric acid (HCA). This form of citric acid inhibits the liver’s ability to make fats out of carbohydrates.118 Carbohydrates are converted to glycogen stores, not fat stores, giving the body a better energy reserve and an increase in stamina.119 Ephedra And Thermogenisis Thermogenesis means “creating heat.” This is one of the ways our bodies have of burning off excess calories and maintaining a constant weight.120 This is an area of weight management research that is being intensely studied. When we repeatedly yo-yo diet or abuse ourselves by eating too much, our thermogenic ability may be reduced. Numerous animal and human studies have confirmed the benefits of ephedra and methylxanthines in inducing weight loss and restoring thermogenic responsiveness.43,44,121
(https://vitanetonline.com:443/forums/Index.cfm?CFApp=1&Message_ID=502) CHITOSAN: The Fiber that Binds Fat  
Date:
June 25, 2005 07:55 PM
Overview Chitosan is a natural product that inhibits fat absorption. It has the potential to revolutionize the process of losing weight and by so doing, reduce the incidence of some of the most devastating Western diseases we face today. Chitosan is indigestable and non-absorbable. Fats bound to chitosan become nonabsorbable thereby negating their caloric value. Chitosan-bound fat leaves the intestinal tract having never entered the bloodstream. Chitosan is remarkable in that it has the abilty to absorb an average of 4 to 5 times its weight in fat.60 The same features that allow chitosan to bind fats endow it with many other valuable properties that work to promote health and prevent disease. Chitosan is a remarkable substance whose time has come.
Chitin, the precursor to Chitosan, was first discovered in mushrooms by the French professor Henri Braconnot in 1811.61 In the 1820’s chitin was also isolated from insects.62 Chitin is an extremely long chain of N-acetyl-D-glucoseamine
FIGURE 2. glucoseamine units. Chitin is the most abundant natural fiber next to cellulose and is similar to cellulose in many respects. The most abundant source of chitin is in the shells of shellfish such as crab and shrimp. The worldwide shellfish harvest is estimated to be able to supply 50,000 tons of chitin annually.63 The harvest in the United States alone could produce over 15,000 tons of chitin each year.64 Chitin has a wide range of uses but that is the subject of another book. Chitosan was discovered in 1859 by Professor C. Rouget.65 It is made by cooking chitin in alkali, much like the process for making natural soaps. After it
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---------------------------------- is cooked the links of the chitosan chain are made up of glucosamine units. Each glucosamine unit contains a free amino group. These groups can take on a positive charge which gives chitosan its amazing properties. The stucture of chitosan is represented schematically in Figure 2. Research on the uses of chitin and Chitosan flourished in the 1930s and early 1940s but the rise of synthetic fibers, like the rise of synthetic medicines, overshadowed the interest in natural products. Interest in natural products, including chitin and chitosan, gained a resurgence in the 1970s and has continued to expand ever since. Uses of Chit osan Some of Chitosan's major uses—both Industrial and Health and Nutritional—are listed in Tables 5 and 6. Water Purification Chitosan has been used for about three decades in water purification processes. 67 When chitosan is spread over oil spills it holds the oil mass together making it easier to clean up the spill. Water purification plants throughout the world use chitosan to remove oils, grease, heavy metals, and fine particulate matter that cause turbidity in waste water streams. Fat Binding/ Weight Loss Like some plant fibers, chitosan is not digestible; therefore it has no caloric value. No matter how much chitosan you ingest, its calorie count remains at
------------------------------ fibers, chitosan’s unique properties give it the ability to significantly bind fat, acting like a “fat sponge” in the digestive tract. Table 7 shows a comparison of chitosan and other natural fibers and their ability to inhibit fat absorption. Under optimal conditions, Chitosan can bind an average of 4 to 5 times its weight with all the lipid aggregates tested.60 (NOTE: This assessment was made without the addition of ascorbic acid which potentiates this action even further.77 Studies in Helsinki have shown that individuals taking chitosan lost an average of 8 percent of their body weight in a 4-week period.76 Chitosan has increased oil-holding capacity over other fibers.108 Among the abundant natural fibers, chitosan is unique. This uniqueness is a result of chitosan’s amino groups which make it an acid absorbing (basic) fiber. Most natural fibers are neutral or acidic. Table 7 summarizes the in vivo effects in animals of various fibers on fecal lipid excretion. As can be seen from the results listed, ingestion of chitosan resulted in 5-10 times more fat excretion than any other fiber tested. D-Glucosamine, the building block of chitosan, is not able to increase fecal fat excretion. This is due to the fact that glucosamine is about 97 percent absorbed while chitosan is nonabsorbable. Fats bound to glucosamine would likely be readily absorbed along with the glucosamine. Chitosan, on the other hand, is not absorbed and therefore fats bound to chitosan can not be absorbed. Cholesterol Control Chitosan has the very unique ability to lower LDL cholesterol (the bad kind) while boosting HDL cholesterol (the good kind).78 Laboratory tests performed on rats showed that “chitosan depresses serum and liver cholesterol levels in cholesterol- fed rats without affecting performance, organ weight or the nature of the feces.”79 Japanese researchers have concluded that Chitosan “appears to be an effective hypocholesterolemic agent.”80 In other words, it can effectively lower blood serum cholesterol levels with no apparent side effects. A study reported in the American Journal of Clinical Nutrition found that Chitosan is as effective in mammals as cholestryramine (a cholesterol lowering drug) in controlling blood serum cholesterol without the deleterious side effects typical of cholestryramine. 81 Chitosan decreased blood cholesterol levels by 66.2 percent.82 It effectively lowered cholesterol absorption more than guar gum or cellulose.83 Laboratory test results indicated that a 7.5% chitosan formula maintained adequate cholesterol levels in rats, despite a dramatic increase in the intake of cholesterol. 84
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