Pectin diet

Experiment 2. In this experiment the basal diet, a 5% HM-pectin diet and a 10% wheat bran diet (corresponding to 5% bran fiber) were fed to groups of 7 rats both with and without 0.5% dietary cholesterol. For comparison, 10% wheat bran and 10% oat bran diets were also studied (without cholesterol). 

Cellulose diet - cholesterol content, mg Pectin diet - cholesterol content, mg... 

The profile of fatty acids in cholesterol esters showed a difference between the two diet groups (Table III). The high levels of palmitate and stearate esters presumably originated from the dietary fat. Since the absorption of palmitate and stearate is low, more of these fatty acids were available in the intestine for esterification. The percentage of oleate was three times greater in the cellulose-diet group than in the pectin-diet group. 

Acid hydrolysis of hitman fecal samples collected after Ingestion of different dietary fibers produced monosaccharides that were related to the fibers Ingested. Dietary fibers studied In five normal male subjects were cellulose, xylan, corn bran and pectin. Increases In monosaccharides In recovered hydrolyzed feces from fiber diets compared to those from the fiber-free diet were galactose for the pectin diet xylose and glucose for the cellulose diet xylose and mannose for the xylan diet and arablnose, xylose, galactose and glucose for the corn bran diet. Comparison of the fecal results to those for the Intact food fibers showed that fermentation of fiber components In the colon was different for each fiber. 

Figure 4. Di- and TriGalA found in colon contents of conventional rats fed with a diet containing low-esterified pectin (above) and in a caecum extract with a standard mixture of OligoGalA (DP 2-5) (below)...

The increasing interest of low-caloric foods in diet is well known. This fact has led to the study of low-methoxyi pectins that allow to obtain jellified products (such as jams, jellies, marmalade) by using very small quantities of sugar. 

Fernandez LM, Lin ECK, Trejo A and McNamara DJ. 1992. Prickly pear (Opuntia sp.) pectin reverses low density lipoprotein receptor suppression induced by a hypercholesterolemic diet in Guinea Pigs. J Nutt 122 2330-2340. 

Diet Codes rwb = red wheat bran wwb = white wheat bran cb = corn bran rb = rice bran pf = psyllium fiber p = pectin c cellulose... 

The laboratory must be informed when the therapeutic regimens include drugs specifically administered to change the blood level of a biochemical constituent. Cholestyramine resin, a nonabsorbable anion exchange resin administered orally to patients with hyperlipoproteinemia produced a 24% decline in serum cholesterol levels in 14 patients with essential hypercholesterolemia. In these patients the mean cholesterol fell from 414 98 mg/100 ml to 176 21 mg/100 ml (FI). Pectin added to the diet caused a 5% decrease in serum cholesterol values (K4), as did an oral hydrophobic colloid (G4). Levels fell in one case from 220 mg/ 100 ml to 160 mg/100 ml (G4). Nicotinic acid, neomycin, and p-chloro-phenoxyisobutyrate have all been used to reduce serum cholesterol (G7). 

The use of high-fiber diets has recently received a great deal of publicity, and many claims have been made for the value of such diets. Fiber in the diet is derived entirely from plant material, either from fruit and vegetables or from cereals, the latter being known as bran. The fiber content in each case is a complex carbohydrate in the form of cellulose, pectin, and lignin. TTiese fibers pass through the human GI tract relatively unaltered by enzymes. 

Hardman, W.E. Cameron, I.L. (1995) Site specific reduction of colon cancer incidence, without a concomitant reduction in cryptal cell proliferation, in 1,2-dimethylhydrazine treated rats by diets containing 10% pectin with 5% or 20% com oil. Carcinogenesis, 16, 1425-1431... 

Elevated serum cholesterol levels are invariably associated with the etiology of atherosclerosis and coronary artery disease, and it has been shown by several investigators that pectin from a variety of sources when supplemented in the diet of a number of laboratory animals, as well as human volunteers, causes lowering... 

Does Citrus Pectin Bind Bile Salts A possible mechanism by which dietary pectin may cause lowering of cholesterol levels in rats has been reported (1 9). In these in vitro studies, pectin was found to inhibit the transport of taurocholic acid from everted sacs of rat intestine. The absorption of labelled cholesterol was depressed by the addition of 5% pectin to the diet as evidenced by increased excretion of labelled cholesterol and diminished cholesterol deposition in the liver. It was concluded from these studies that pectin lowers cholesterol levels in cholesterol-fed rats primarily by binding bile salts and, consequently, by impairing cholesterol absorption. Results similar to those obtained with dietary pectin and described have also been reported for other non-nutritive substances such as guar gum, psyllium seed colloid and seruglucan (20). 

Based on our knowledge of the facts that (a) lipoproteins are carriers of cholesterol in the blood stream, (b) they are involved in atherogenesis,(c) pectin when supplemented in diet causes lowering of serum and/or liver cholesterol in man as well as a number of laboratory animals and (d) polyanionic glycosaminoglycans interact with lipoproteins, it was of interest to us to investigate the interaction of polyanionic pectin with lipoproteins in order to explain the biochemical basis by which pectin may cause lowering of serum/liver cholesterol levels. 

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. 

There are several ways pectin could reduce serum cholesterol. In studies with human subjects, fecal excretion of bile acids, fatty acids, and total steroids increased when subjects were fed 15-40 g/day of pectin (58, 63, 64). Since pectin usually lowers serum cholesterol only when cholesterol is present in the diet, it seems that pectin might act by reducing cholesterol absorption. Several groups have found that in rats dietary... 

Impairment of bile acid absorption and consequent loss of these acids via excretion presumably causes an increase in hepatic conversion of cholesterol to bile acids. This conversion lowers serum cholesterol, particularly when serum contains high levels of cholesterol derived from dietary intake. However, when fed with a cholesterol-free diet, 10% pectin supplementation stimulated a 3-fold increase in cholesterol biosynthesis (77). Biosynthesis of phospholipids and triglycerides also increased significantly hence, it was suggested that these increases occurred in response to diminished fat absorption occasioned by pectin intake. This compensatory biosynthesis of cholesterol and lipids may account for pectin s inability (in most cases) to lower serum cholesterol levels in animals fed cholesterol-free diets. 

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