Psyllium Hydrocolloid Research Articles

Cholesterol 7α-Hydroxylase Activity is Increased by Dietary Modification with Psyllium Hydrocolloid, Pectin, Cholesterol and Cholestyramine in Rats

Sources of dietary fiber known to alter cholesterol metabolism and/or bile acid pool size were fed to rats, and activity of the rate-limiting step in bile acid synthesis, cholesterol 7α-hydroxylase, was measured. In the first experiment, semipurified diets containing 5% cellulose, psyllium hydrocolloid, pectin or oat bran as dietary fiber sources or 2% cholestyramine were fed to groups of 10 male Wistar rats for 4 wk. In the second experiment, groups of six rats were fed diets containing 5% cellulose, rice bran, oat bran or psyllium with and without 0.25% cholesterol. In the first experiment, the activity of cholesterol 7α-hydroxylase (pmol·min-1·mg protein-1) was highest in the cholestyramine-treated group (95.6 ± 3.6), followed by groups fed psyllium (35.5 ± 3.5) or pectin (36.0 ± 4.5), which exhibited more than twice the enzyme activity of groups fed cellulose (16.9 ± 1.9) or oat bran (12.3 ± 2.0). In the second experiment, feeding cholesterol resulted in significantly higher enzyme activity when cellulose (65%), oat bran (118%) and rice bran (60%) were fed, but no difference in activity was observed when cholesterol was added to the psyllium-containing diet. Higher activity of cholesterol 7α-hydroxylase when pectin or psyllium rather than cellulose was fed may explain the almost twofold higher bile acid pool sizes previously reported in response to feeding either of these fibers. These data support the hypothesis that the hypocholesterolemic effect of soluble fibers is modulated through increased synthesis and therefore pool size of bile acids.

Correction to: Macrogol (polyethylene glycol) 4000 without electrolytes in the symptomatic treatment of chronic constipation: a profile of its use.

[This corrects the article DOI: 10.1007/s40267-018-0532-0.].

Macrogol (polyethylene glycol) 4000 without electrolytes in the symptomatic treatment of chronic constipation: a profile of its use.

Macrogol 4000, a biologically inert, non-absorbable osmotic laxative, is a highly effective and well-tolerated first-line option for the treatment of the symptoms of chronic idiopathic/functional constipation in children and adults. High-molecular-weight (HMW) macrogols ± electrolytes have generally similar efficacy profiles; however, the taste of macrogol 4000 is generally preferred over that of macrogol 3350 + electrolytes. Macrogol 4000 is more effective than lactulose in improving stool frequency and consistency, and is associated with less vomiting and flatulence. Comparisons with other osmotic and bulk-forming laxatives are limited, with macrogol 4000 being at least as, or more effective than, psyllium hydrocolloid and magnesium hydroxide in treating chronic constipation. Current clinical treatment guidelines recommend the use of HMW macrogols over the use of lactulose and bulk-forming laxative in the symptomatic treatment of constipation in children and adults.

Development and quality characterization of liquid Kashk by incorporating psyllium (Plantago ovata Forsk) hydrocolloid gel

The functionality of psyllium hydrocolloid gel (PHG, 0.1–0.75%) to improve physicochemical (pH, syneresis, physical stability and lightness), rheological (viscosity and flow behavior), microstructural and sensorial characteristics of an ethnic acid-fermented dairy product “Kashk” with different contents of dried Kashk powder (DKP, 15–25%) was investigated. Results showed the low-viscous liquid Kashks containing 0.1% PHG at all DKP levels had the highest syneresis, instability and lightness amounts. Scanning electron microscopy and laser diffraction particle size analysis exhibited the increasing PHG content by 0.5% reduced aggregated particles size in a uniform monomodal distribution, whereas the weaker interaction of polysaccharide-casein at 0.75% PHG led to an increase in the number of unadsorbed polysaccharides. A highly negative correlation was also found between the viscosity and phase separation percentage, and between the particles size and overall acceptability sensory attribute. According to the quality evaluations, the best formulation was composed of 25% DKP and 0.5% PHG.

Development and characterization of a novel biodegradable edible film obtained from psyllium seed (Plantago ovata Forsk)

Abstract In this study, the physical, thermal and mechanical properties of a novel edible film based on psyllium hydrocolloid (PH) were investigated. PH films were prepared by incorporation of three levels of glycerol (15%, 25%, and 35% w/w). As glycerol concentration increased, water vapor permeability (WVP), percent of elongation (E%) and water solubility of PH films increased whilst, tensile strength (TS), surface hydrophobicity and glass transition point (Tg) decreased significantly. At the level of 15% (W/W) of glycerol, PH films showed the lowest WVP values (1.16 × 10−10 g H2O m−2 s−1 MPa−1), E% (24.57%) and water solubility (47.69%) and the highest values for TS (14.31 MPa), water contact angle (84.47°) and Tg (175.2 °C). By increasing glycerol concentration, PH films became slightly greenish and yellowish in color but still transparent in appearance. This study revealed that the psyllium hydrocolloid had a good potential to be used in producing edible films with interesting specifications.

Survival of Saccharomyces boulardii in the Rat Gastrointestinal Tract and Effects of Dietary Fiber

The present study was directed to determine the sites of destructive metabolism of the biotherapeutic yeast Saccharomyces boulardii and the influences of dietary fiber on survival. Both single dose and steady state experiments implicate the lower bowel as an important influence in the metabolic loss of viability of S. boulardii in rats. Studies in rats revealed that diets containing psyllium hydrocolloid or polycarbophil increased fecal steady state levels of S. boulardii by 4.3-fold and 3.2-fold, respectively, compared to levels in fiber-free diet fed animals. Pectin and alginic acid had no effect. Psyllium fiber increased steady state recovery in all experiments in which the S. boulardii was given orally (p<0.04) but did not when S. boulardii was given via a cecal cannula, suggesting that this fiber may act in the terminal ileum at steady state. Only specific types of dietary fiber can increase the number of viable S. boulardii passing through the gastrointestinal tract at steady state dosing. Key words: Saccharomyces boulardii , biotherapeutic agents, probiotics, dietary fiber, gastrointestinal tract, drug metabolism.

Dietary Psyllium Increases Fecal Bile Acid Excretion, Total Steroid Excretion and Bile Acid Biosynthesis in Rats

Psyllium, a source of dietary fiber rich in soluble components results in lower serum cholesterol concentration in several species. Suggested mechanisms for the hypocholesterolemic effect include a greater excretion of fecal bile acids and total steroids, and up-regulation of bile acid biosynthesis. The activity of cholesterol 7α-hydroxylase (7αOHase), the rate limiting enzyme in bile acid biosynthesis, is higher in rats fed 5% psyllium. Whether this higher activity corresponds to an increase in mRNA levels has not been determined. Four groups of 10 rats were fed a semipurified diet containing 5% cellulose (CEL; control), 5% cellulose plus 1% cholic acid (CCA), 5% cellulose plus 2% cholestyramine (CHY) or 5% psyllium hydrocolloid (PSY) for 3 wk. Liver cholesterol concentration, fecal bile acid and total steroid excretion, 7αOHase activity and 7αOHase mRNA levels were measured. Liver cholesterol content in rats fed CCA was significantly higher than in all other groups. Rats fed CHY and PSY had significantly lower liver cholesterol content than those fed CEL. Total fecal steroid and bile acid excretions were significantly greater in rats fed CCA, CHY and PSY than in those fed CEL. Activities and mRNA levels of 7αOHase in rats fed CHY and PSY were significantly higher than in rats fed CEL or CCA. These data indicate that feeding psyllium to rats increases fecal bile acid and total steroid excretion as well as 7αOHase activity and 7αOHase mRNA levels.

Dietary Psyllium Hydrocolloid and Pectin Increase Bile Acid Pool Size and Change Bile Acid Composition in Rats

AbstractBile acid composition, synthetic rate and pool size were determined in rats fed diets containing 5 g cellulose, 5 g pectin or 5 g psyllium hydrocolloid/100 g diet using the washout technique. Bile acid pool sizes were similar for pectin- and psyllium-fed rats, and both were higher than the pool size for rats fed cellulose (5.48 ± 1.22, 4.70 ± 0.71 and 1.77 ± 0.41 µmol/100 g body wt, respectively). Bile acid secretion rates showed a similar pattern [1730 ± 496, 1551 ± 252 and 572 ± 88 nmol/(h·100 g body wt)], as did basal synthetic rates [129 ± 25, 126 ± 42 and 87 ± 18 pmol/(h·100 g body wt)]. Individual and total bile acid pool sizes were generally higher in animals fed the pectin- or psyllium-supplemented diet compared with rats fed cellulose. Pectin or psyllium consumption resulted in a lower hydrophobicity of the bile acid pool and a lower ratio of circulating 12α-hydroxylated to non-12α-hydroxylated bile acids compared with cellulose consumption. This reduced hydrophobicity has been shown to reduce feedback inhibition of bile acid synthesis and may be responsible for the larger bile acid pool size. Changes in the location of reabsorption of bile acids may also be responsible for changes in the pool size and composition. These changes are characteristic of greater sterol excretion

The effect of dietary psyllium hydrocolloid and lignin on bile.

Animal experiments suggest that supplementing the diet with either psyllium seed husk or lignin alters the ratio of deoxycholic acid to chenodeoxycholic in bile. In this study dosages of psyllium seed husk or lignin acceptable to patients with gallstones do not appear to alter the relative amounts of cholesterol, or individual bile acids in the bile.

Breakdown of psyllium hydrocolloid by strains of Bacterioides ovatus from the human intestinal tract.

Strains of Bacteroides ovatus from human feces produced extracellular enzymes which degraded psyllium hydrocolloid. Other species of saccharolytic bacteria which are found in high concentrations in human feces did not degrade psyllium.

Effect of dietary fibre on gallstone formation in hamsters.

This study aimed at investigating the effect of different sources of dietary fibre on gallstone formation in hamsters. The substances studied were pectin, lignin and psyllium hydrocolloid. The two latter compounds protected hamsters against cholesterol gallstone formation. Lignin resulted in a decrease of the deoxycholic acid conentration and in a rise of the cholic/chenodeoxycholic acid ratio. These changes which are similar to those observed with cholestyramine suggest that lignin acts as a bile acid sequestrant. Psyllium hydrocolloid effected a similar shift of the cholic/chenodeoxycholic acid ratio but it also resulted in a rise of the deoxycholic concentration. This latter finding is not compatible with a bile acid sequestering role of this compound. The addition of alcohol to the drinking-water resulted in the formation of stones rich in pigment. Under these conditions the tendency to form such stones was not checked by either of the investigated substances.

Effects of psyllium hydrocolloid on bile acid metabolism in normal and hypophysectomized rats.

SummaryA study was made of the effects of diets supplemented with psyllium hydro-colloid (Metamucil) on bile acid half-lives and pool sizes in normal and hypophysectomized rats. Metamucil decreased bile acid half-lives by about 40% in both normal and hypophysectomized rats. The mucilloid also effected small but significant increases in the size of the bile acid pools. It was demonstrated that Metamucil increases bile acid excretion in rats by increasing the turnover rate and size of the bile acid pool. Pituitary and target gland hormones have little or no effect on the drug's ability to effect these changes.