Pectin hypocholesterolemic effect

The importance of some pectic substances (pectin or pectins) either due to the great amounts that certain raw materials contain, or the existence of any specific food use, as well as its hypocholesterolemic effect (based in in vitro and in vivo studies) would explain the increasing interest on deepening physico-chemical studies of pectic substances. 

Bile acids and salts have been found to enhance the absorption of both calcium and vitamin D hence, to increase calcium absorption both directly and indirectly (3,37). However, the ability of some dietary fibers such as lignin and pectin to absorb conjugated and deconjugated bile salts onto their surfaces to be excreted in the feces (a mechanism credited to the hypocholesterolemic effect of some dietary fibers) may result in an overall decrease in calcium absorption from the gastrointestinal tract (7,33,38-40). 

In studying results from both chickens and man, Fisher et al. (67) concluded that pectin has a hypocholesterolemic effect only when fed with dietary cholesterol. On cholesterol-free diets, plasma cholesterol is not affected by dietary pectin. Subjects fed pectin with a cholesterol-containing diet had plasma cholesterol levels that were lower relative to those of subjects on the cholesterol control diet, but not relative to those of subjects on a cholesterol-free control diet. 

Pfeffer et al. (82) have found that bile salt binding activity of commercial citrus pectins was lost if these products were dissolved, filtered, centrifuged, and reprecipitated before testing. Binding activity was concentrated in the residue pellet from centrifugation, which was found to be fine diatomaceous earth. This contaminant was probably introduced during filtration steps in processing and purification of pectin. The authors concluded that any hypocholesterolemic effect of commercial pectin was due solely to its diatomaceous earth contamination. 

It remains to be seen if calcium pectate will have a greater hypocholesterolemic effect than has been reported for commercial pectins in feeding studies (11-15). 

Yamaguchi F., Uchida S., Watabe S., Kojima H., Shimizu N., Hatanaka C., Relationship between molecular weights of pectin and hypocholesterolemic effects in rats, Biosci. Biotechnol. Biochem., 59(11), 1995, 2130-2131. 

Over the last 20 years many studies have shown that dietary fiber may have a hypocholesterolemic effeet[111,112] However, the largely held public belief that all fibers are hypolipidemic is not supported by the experimental data. Bran, for instance, which is mainly constituted by cellulose and hemicellulose, does not seem to have any effect on serum lipids[113], whereas it has been shown that pectin, guar-gum and alfa-alfa saponins have a definite hypocholesterolemic effect[114,115,116] ... 

Pectin with 62% D.E. largely counteracted the increase in liver cholesterol levels brought about by dietary cholesterol. Low ester pectin (30% D.E.), polygalacturonic acid (PGA), and 50% esterified PGA were all without effect. Conflicting reports on the efficacy of pectin as a hypocholesterolemic agent may be due to variations in these parameters. For example, citrus pectin was found to be more effective than tomato pectin in lowering serum and hepatic cholesterol levels of rats (79). 

Compounds with different structures but with the same therapeutic activity isolated from different plant species act as active moieties for the treatment of particular diseases. Some of these compounds have been abandoned due to toxicity but these compounds apparently do not cause serious adverse effects. Some of these active principles originate from edible plants and their inclusion in the diet would undoubtedly be of some value because of their hypocholesterolemic potential. Several phytoconstituents including inulin, pectin, gugglu lipids, flavonoids, ginkoloids, saponins, tannins, and others obtained from various plant sources have proven hypolipidemic potentials as has been further explained in Tables I and II. The chemical structures of a few potential phytoconstituents with hypolipidemic activity are shown in Figure 2. It is hoped that as new additions are made to the list of these active compounds causing only minimum untoward side effects, these naturally... 

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