Effect of pectin and cellulose on formation and regression of gallstones in hamsters

A buckwheat protein product suppresses gallstone formation and plasma cholesterol more strongly than soy protein isolate in hamsters

This study was conducted to investigate the effects of a buckwheat protein product (BWP) on plasma cholesterol, gallbladder bile composition and fecal steroid excretion in hamsters fed diets with 5 g/kg cholesterol. Diets also contained 200 g/kg of casein, soy protein isolate (SPI) or BWP as protein sources. After 2 wk, plasma and liver concentrations of cholesterol in the hamsters fed BWP were significantly lower than those in the hamsters fed casein and SPI. The molar proportion of cholesterol in gallbladder bile was significantly lower in the BWP group than in the other groups, whereas that of bile acids was slightly higher in the BWP group (P Collapse

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MESH Headings

• Animals
• Bile/chemistry
• Cholelithiasis/pathology
• Cholesterol/blood
• Cholesterol, Dietary/pharmacology
• Cricetinae
• Energy Intake/drug effects
• Fagopyrum
• Feces/chemistry
• Lipid Metabolism
• Lipids/blood
• Liver/metabolism
• Male
• Mesocricetus
• Plant Proteins/pharmacology
• Glycine max
• Weight Gain/drug effects

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Affiliation(s)

H Tomotake Development, Health Care, Kissei Pharmaceutical Company, Ltd., Matsumoto 399-8710, Japan
I Shimaoka
J Kayashita
F Yokoyama
M Nakajoh
N Kato

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Soluble dietary fiber protects against cholesterol gallstone formation

BACKGROUND

Epidemiological studies have suggested that soluble dietary fibers are hypocholesterolemic and may inhibit cholelithiasis.

METHODS

Thirty prairie dogs were placed on a cholesterol-supplemented lithogenic diet. Ten animals received 5% psyllium (PSY) and 10 animals received 5% cellulose. After 6 weeks all gallbladders were inspected for stones; blood and bile were collected for analysis.

RESULTS

Cholesterol stones were present in 8 of 10 of the control animals, in 6 of 10 of the cellulose group, and 3 of 10 of the PSY animals (P <0.05). Concentrations of cholesterol and chenodeoxycholic acid (CDCA) were significantly lower in the PSY group compared with controls (0.49 versus 0.88 mM and 4.2 versus 9.2 mM, respectively) leading to a significant reduction in the cholesterol saturation index (0.62 versus 1.2).

CONCLUSIONS

A dietary soluble fiber (PSY) inhibits cholesterol stone formation by reducing the biliary cholesterol saturation index. This protective effect is associated with a selective decrease in biliary cholesterol and CDCA.

Effect of different varieties of pectin and guar gum on plasma, hepatic and biliary lipids and cholesterol gallstone formation in hamsters fed on high-cholesterol diets

The effect of high- (hePE) and low- (lePE) esterification pectin and high- (hvGG) and low-(lvGG) viscosity guar gum on plasma, hepatic and biliary lipids and on prevention of cholesterol gallstones was investigated in male golden Syrian hamsters (Mesocricetus auratus). Hamsters were fed on cholesterol-rich (4 g/kg), gallstone-inducing diets for 6 weeks. The diets were supplemented with 80 g hePE, lePE, hvGG or lvGG/kg or 80 g additional cellulose/kg. No significant differences in plasma total cholesterol and triacylglycerol concentrations between hvGG and lvGG and the gallstone-inducing or cellulose-enriched diets were observed. The hePE diet produced a 16% (non-significant) reduction in total plasma cholesterol but significantly decreased the plasma triacylglycerol level by 45%. The lePE diet caused only minor changes in plasma lipids. Hepatic cholesterol concentrations were significantly higher in hamsters fed on hvGG, lvGG, hePE or lePE primarily due to the accumulation of esterified cholesterol. Supersaturated bile samples, with lithogenic indices ranging from 1.6 to 2.0, were determined with all diets. The hePE and lePE diets slightly altered the bile acid profile by increasing glycocholic acid and decreasing taurochenodeoxycholic acid concentrations resulting in a higher cholic:chenodeoxycholic acid ratio. Cholesterol gallstone formation was not substantially inhibited by the two varieties of pectin and guar gum. The hvGG, lvGG, hePE and lePE diets did not alter faecal weight and caused only minor increases in faecal bile acid excretion. In general, the present findings demonstrate that dietary pectins and guar gums had only minor effects on cholesterol metabolism and did not prevent cholesterol gallstone formation in this hamster model. Possible explanations for this lack of a distinct response to pectin and guar gum are discussed.

Effects of rye bran, oat bran and soya-bean fibre on bile composition, gallstone formation, gall-bladder morphology and serum cholesterol in Syrian golden hamsters (Mesocricetus auratus)

The effects of rye bran, oat bran and soya-bean fibre on serum lipids, bile composition and gallstone formation were studied in male Syrian golden hamsters (Mesocricetus auratus). The control groups received fibre-free stone-provoking (O1 diet) or non-stone-provoking (O2 diet) diets. The serum cholesterol levels were lower for all groups fed on the diets supplemented with the dietary fibre sources compared with the control groups. The total content of bile acids in bile was higher in groups given rye-bran diets compared with the corresponding controls. The proportion of cholic acid was higher and that of chenodeoxycholic and lithocholic acid lower in the groups given rye-bran-, oat-bran- or soya-bean-fibre-supplemented diets, compared with the corresponding controls. The secondary:primary bile acid ratio was lower in the group given the rye-bran-supplemented O1 diet. The lithocholic:deoxycholic acid ratio was lower in the groups given rye-bran-, oat-bran- or soya-bean-fibre-supplemented diets than in the corresponding controls. A lower frequency of gallstones was observed only for the group receiving the rye-bran-supplemented O1 diet while the lithogenic index was lower in the groups given the rye-bran-supplemented O2 diet. A decreased epithelial volume density of the gall-bladder and an increased smooth muscular volume density were observed in animals given oat-bran- and rye-bran-supplemented O1 diets, whereas for the soya-bean-fibre-supplemented O1 diet, only the smooth muscular volume density was increased.

Dietary recommendations to prevent coronary heart disease

The evidence that limiting dietary saturated fat and cholesterol will lower LDL cholesterol and contribute to the reduction in risk of cardiovascular disease is adequate for sound dietary recommendations to patients and to the public at large. Reduction of intake of all saturated fats to less than 10% of calories is a practical and achievable goal for Western man. Further reduction to less than 7% of calories is possible with a motivated and well instructed patient. The mechanism by which saturated fatty acids, particularly palmitate and laurate raise LDL cholesterol need detailed biochemical and physiologic study. Dietary cholesterol is unnecessary and clearly contributes to vascular disease in Western man. This vascular effect appears to be only partially explained by its effect on LDL cholesterol. Reduction to less than 300 mg per day for men of average size is achievable. Women and those eating fewer calories should strive for even less. Monounsaturated fats (oleic acid) can be consumed at levels of 20% of calories without significant concern if total calories are within limits to maintain desirable weight. Omega-6 polyunsaturated fats do not offer a significant health concern and need not be limited below the current intake of 7% of calories in the United States. Populations eating higher levels should be monitored to determine if such intakes are associated with either improved health or long-term ill effects since this level of intake has not been a long-standing tradition in any known culture. Omega-3 fatty acids might be increased to 2 or 3% of calories with potential benefit. Eating fish and marine animals is the most clearly documented safe method for achieving this. Larger intakes and particularly the use of fish oil supplements is unproven therapy for vascular disease prevention and needs much further study as a medical treatment for a variety of disorders. Protein intake is more than adequate in the USA and further increases could have negative effects on the prevalence of renal disease and osteoporosis. Although these issues are of hypothetical interest at the moment, they are worthy of considerable investigation. Complex carbohydrates consumed as components of vegetables, fruits and grains should be considered proven safe and healthful. Increasing calories from these sources at the expense of saturated fats and simple sugars should prove highly beneficial to Western populations. Fiber from these sources may have beneficial effects on blood cholesterol and intestinal function. Soluble fiber is documented to lower LDL cholesterol but the mechanism of this effect is not established and is worthy of considerable study.(ABSTRACT TRUNCATED AT 400 WORDS)

The influence of barley fibre on bile composition, gallstone formation, serum cholesterol and intestinal morphology in hamsters

Frequency of gallstones, concentration of bile acids and cholesterol in bile, concentration of cholesterol in serum, and structure of the small intestinal mucosa were analyzed in male Syrian Golden hamsters fed a stone provoking fibre-free diet with or without supplementation of brewer's spent grain (BSG), a concentrated barley fibre source from the by-product of brewing. A significantly lower frequency of gallstones was found in the animals with 10% BSG dietary supplementation. Addition of 30% BSG after an initial 6-week period with a fibre-free, stone provoking diet seemed to dissolve previously formed gallstones. Total bile acid concentration was higher in bile from animals given a diet supplemented with 10% BSG. In addition, the cholesterol concentration in both serum and bile was lower in the 30% BSG supplemented group. Structurally, a 10% BSG supplementation decreased ileal epithelium height whereas a high supplementation (30%) of BSG induced a decrease in epithelial height both of jejunal and ileal mucosa. The results show that BSG has significant effects on the metabolism of bile acids and cholesterol as well as on the morphology of the small intestinal mucosa.

Lack of regression of preestablished gallstones in mice

Feeding a high cholesterol, high cholic acid diet to mice for 28 days caused increased concentrations of plasma and liver cholesterol and formation of gallstones. Removal of cholesterol and cholic acid from the diet led to normalization of plasma and liver cholesterol within 28 days. Regression of the preestablished gallstones did not occur within 107 days.