Fecal Steroid Excretion Research Articles

Pentapeptide IIAEK ameliorates cholesterol metabolism via the suppression of intestinal cholesterol absorption in mice.

Dietary protein-derived peptides are effective in improving dyslipidemia and hypercholesterolemia. We previously identified a novel cholesterol-lowering pentapeptide IIAEK from milk beta-lactoglobulin. However, it remains unclear whether IIAEK affects the micellar solubility of cholesterol and the bile acid-binding ability to lower cholesterol. Moreover, there is no direct evidence that IIAEK inhibits intestinal cholesterol absorption and affects hepatic cholesterol and fecal steroid excretion in vivo. Herein, we showed that IIAEK did not affect the micellar solubility of cholesterol and the bile acid-binding ability. However, we found that IIAEK decreased serum and liver cholesterol levels and increased fecal steroid excretion in mice. Interestingly, IIAEK markedly suppressed the intestinal absorption of [3H]-cholesterol in mice. In conclusion, we found that IIAEK ameliorated cholesterol metabolism by suppressing intestinal cholesterol absorption without affecting in vitro micellar solubility of cholesterol and the bile acid-binding ability in mice.

Breeding Buckwheat for Increased Levels and Improved Quality of Protein.

Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) and common buckwheat (Fagopyrum esculentum Moench) are important sources of proteins with balanced amino-acid compositions, and thus of high nutritional value. The polyphenols naturally present in Tartary buckwheat and common buckwheat lower the true digestibility of the proteins. Digestion-resistant peptides are a vehicle for fecal excretion of steroids, and in this way, for bile acid elimination and reduction of cholesterol concentrations in serum. Buckwheat proteins are more effective compared to soy proteins for the prevention of gallstone formation. Tartary and common buckwheat grain that contains appropriate amounts of selenium-containing amino acids can be produced as functional food products. The protein-rich by-products of buckwheat are a good source of bioactive substances that can suppress colon carcinogenesis by reducing cell proliferation. The grain embryo is a rich source of proteins, so breeding buckwheat with larger embryos is a possible strategy to increase protein levels in Tartary and common buckwheat grain. However, chemical analysis of the grain is the most relevant criterion for assessing grain protein levels and quality.

Rare sugars, d-allulose, d-tagatose and d-sorbose, differently modulate lipid metabolism in rats.

Rare sugars including d-allulose, d-tagatose, and d-sorbose are present in limited quantities in nature; some of these rare sugars are now commercially produced using microbial enzymes. Apart from the anti-obesity and anti-hyperglycaemic activities of d-allulose, effects of these sugars on lipid metabolism have not been investigated. Therefore, we aimed to determine if and how d-tagatose and d-sorbose modulate lipid metabolism in rats. After feeding these rare sugars to rats, parameters on lipid metabolism were determined. No diet-related effects were observed on body weight and food intake. Hepatic lipogenic enzyme activity was lowered by d-allulose and d-sorbose but increased by d-tagatose. Faecal fatty acid excretion was non-significantly decreased by d-allulose, but significantly increased by d-sorbose without affecting faecal steroid excretion. A trend toward reduced adipose tissue weight was observed in groups fed rare sugars. Serum adiponectin levels were decreased by d-sorbose relative to the control. Gene expression of cholesterol metabolism-related liver proteins tended to be down-regulated by d-allulose and d-sorbose but not by d-tagatose. In the small intestine, SR-B1 mRNA expression was suppressed by d-sorbose. Lipid metabolism in rats varies with rare sugars. Application of rare sugars to functional foods for healthy body weight maintenance requires further studies. © 2017 Society of Chemical Industry.

Okara, a By-Product of Tofu Manufacturing, Modifies Triglyceride Metabolism at the Intestinal and Hepatic Levels.

Irrespective of a well-known hypocholesterolemic action, a few studies have shown a hypotriglyceridemic potential of okara, a by-product of tofu manufacturing. Okara was fed to rats at the level of 2.5 and 5.0% as dietary protein for 4 wk, and serum and hepatic lipid levels were determined. In addition, soy flour, which has a well-known hypolipidemic action, was used to compare effects on lipid metabolism. Mechanisms of action were further evaluated by measuring hepatic enzyme activity, gene expression of lipid metabolism-related proteins and fecal excretion of lipids. Feeding the okara diets resulted in a significantly lower weight of the liver and adipose tissue in a dose-dependent manner. Serum triglyceride levels were more than 50% lower in rats fed the okara diets compared to those fed the control diet. Enzyme activities of fatty acid synthesis were significantly lowered by the okara diet. Fecal weight was significantly higher in the okara group than in the control group, and fecal excretion of steroids tended to be higher. Therefore, a relatively low amount of okara may exert hypotriglyceridemic action in rats in part through decreased hepatic triglyceride synthesis. The present study also suggests an involvement of intestinal events in altered lipid metabolism in rats fed the okara diets.

Cholesterol-lowering effect of rice bran protein containing bile acid-binding proteins.

Dietary plant protein is well known to reduce serum cholesterol levels. Rice bran is a by-product of rice milling and is a good source of protein. The present study examined whether feeding rats a high-cholesterol diet containing 10% rice bran protein (RBP) for 10 d affected cholesterol metabolism. Rats fed dietary RBP had lower serum total cholesterol levels and increased excretion of fecal steroids, such as cholesterol and bile acids, than those fed dietary casein. In vitro assays showed that RBP strongly bound to taurocholate, and inhibited the micellar solubility of cholesterol, compared with casein. Moreover, the bile acid-binding proteins of the RBP were eluted by a chromatographic column conjugated with cholic acid, and one of them was identified as hypothetical protein OsJ_13801 (NCBI accession No. EAZ29742) using MALDI-TOF mass spectrometry analysis. These results suggest that the hypocholesterolemic action of the RBP may be caused by the bile acid-binding proteins.

Peptides Identified in Soybean Protein Increase Plasma Cholesterol in Mice on Hypercholesterolemic Diets

The in vitro micellar cholesterol displacement assay has been used to identify peptides that may potentially reduce cholesterol in vivo. Two of these peptides, LPYPR and WGAPSL, derived from soybean protein (SP) that have been reported to displace cholesterol from micelles were tested by feeding them as a part of a hypercholesterolemic diet to mice for 3 weeks. Except reduction of very low-density lipoprotein cholesterol (VLDL-C) and triglyceride contents, the peptide-containing diets increased plasma cholesterol content with the increasing dose of the peptides. Mice fed diets supplemented with the peptides also had lower fecal bile acid excretion. Negative correlations between fecal bile acid excretion and plasma total cholesterol content (r = -0.876, P = 0.062) and non-HDL-C content (r = -0.831, P = 0.084) were observed. The mRNA levels of the genes for cholesterol and bile acid metabolism, CYP51, LDLR, CYP7A1, and LPL, were up-regulated in mice fed diets supplemented with peptides except the group fed the low dose of WGAPSL. The results suggested that higher plasma total cholesterol content possibly due to lower fecal steroid excretion as well as lower VLDL-C and triglyceride contents might due to the up-regulated expression levels of the genes CYP51, LDLR, and LPL.

Medium-Chain Fatty Acids Enhanced the Excretion of Fecal Cholesterol and Cholic Acid in C57BL/6J Mice Fed a Cholesterol-Rich Diet

The objective of the present study was to investigate the cholesterol-reducing effect of medium-chain fatty acids (MCFAs) completed by elevated excretion of fecal neutral steroids and/or bile acids. Blood and liver lipid profiles, fecal neutral steroids, bile acids, and mRNA and protein expression of the genes relevant to cholesterol homeostasis were measured and analyzed in C57BL/6J mice fed a cholesterol-rich diet with 2% caprylic acid or capric acid for 12 weeks. Blood total cholesterol and low-density lipoprotein cholesterol (LDL-c) levels were reduced significantly as compared to diet with palmitic acid or stearic acid. Caprylic acid promoted the excretion of fecal neutral steroids, especially cholesterol. The excretion of fecal bile acids, mainly in the form of cholic acid was enhanced and accompanied by elevated expression of mRNA and the protein of hepatic cholesterol 7α-hydroxylase (CYP7A1). These results indicate that MCFAs can reduce blood cholesterol by promoting the excretion of fecal cholesterol and cholic acid.

Effect of Cheonggukjang made with germinated soybean on lipid contents and fecal excretion of neutral steroids in rats fed a high cholesterol diet

This study was conducted to investigate the effect of cheonggukjang made with soybean germinated under dark and light conditions on lipid content and fecal neutral steroids in rats fed with a high cholesterol diet. Rats were divided into 4 groups: high cholesterol diet (HC); high cholesterol diet containing normal cheonggukjang (HNC); high cholesterol diet containing cheonggukjang made with soybean germinated under dark condition (HDC); high cholesterol diet containing cheonggukjang made with soybean germinated under light condition (HLC). Dietary supplementation with light-reacted cheonggukjang decreased hepatic triglycerides, compared with the other groups. Fecal excretion of total lipids and triglycerides increased when fed with cheonggukjang made with soybean germinated under light condition. Fecal excretion of coprostanol, cholesterol, and coprostanone tended to increase in the cheonggukjang-supplemented groups. These results suggest that dietary supplementation with cheonggukjang made with germinated soybean might prevent hyperlipidemia by improving the lipid metabolism through decreasing the liver triglycerides contents and increasing fecal excretion of triglycerides.

Mechanisms Underlying Decreased Hepatic Triacylglycerol and Cholesterol by Dietary Bitter Melon Extract in the Rat

In these studies, we focused on finding the mechanism(s) underlying the bitter melon (Momordica charantia L.) methanol fraction (MF)-dependent reduction in the concentration of hepatic triacylglycerol (TAG) and cholesterol in the rat. Rats were fed diets containing low (5 %) fat for 2 weeks (experiment 1), or low (5 %) and high (15 %) fat for a longer period of 8 weeks (experiment 2). MF was supplemented at 1 % level in both experiments. After feeding, rats were sacrificed, and their livers were prepared as slices and hepatocytes, followed by incubation with [1(2)-¹⁴C] acetate or [1-¹⁴C] oleic acid (18:1 n-6). Under these conditions, we found that rats fed diets containing MF, as compared to those without MF, showed: (1) no adverse effects on food intake and growth, (2) a decreased hepatic TAG and total cholesterol, irrespective of the difference in dietary fat level or feeding period, and (3) a decreased incorporation of [1(2)-(¹⁴C] acetate and [1-¹⁴C] oleic acid into TAG of liver slices and hepatocytes. MF-supplemented rats also showed no altered incorporation of labeled acetate into cholesterol and cholesterol ester, an increased fecal excretion of neutral steroids, but not of acidic steroids, and an enhanced mRNA abundance of carnitine palmitoylacyltransferase I, which is the rate-limiting enzyme for fatty acid oxidation. These results suggest that dietary MF decreases hepatic TAG synthesis while enhancing fatty acid oxidation, thereby reducing the concentration of hepatic TAG. The liver cholesterol-lowering effect of MF, however, is probably mediated through an increased fecal excretion of neutral steroids, without an effect on cholesterogenesis.

Rice α-globulin decreases serum cholesterol concentrations in rats fed a hypercholesterolemic diet and ameliorates atherosclerotic lesions in apolipoprotein E-deficient mice

The hypocholesterolemic and antiatherogenic effects of rice α-globulin remain unclear. We investigated the hypocholesterolemic effect of rice α-globulin in rats fed a hypercholesterolemic diet. The rats were divided into 4 groups and were orally administrated the following three proteins or a vehicle for 4weeks: rice protein, rice α-globulin, or soy β-conglycinin at a dose of 100mg/kg body weight or carboxymethylcellulose to the control rats. In the rice α-globulin group, serum cholesterol concentrations were 28% lower than the control group and fecal neutral steroid excretion was increased by 30%. The hypocholesterolemic effect of rice α-globulin was equal to soy β-conglycinin in SD rats fed the hypercholesterolemic diet. However, the serum cholesterol concentrations in the rice protein group did not change compared to the control group. To investigate the antiatherogenic effects of rice α-globulin, male apolipoprotein E-deficient mice were orally administered the same dose of rice α-globulin for 9weeks. The en face lesion area in the aorta was 46% lower than in the control group. In conclusion, administration of rice α-globulin improves hypercholesterolemia in rats fed a hypercholesterolemic diet by increasing the fecal excretion of neutral sterols, and inhibits atherosclerosis development in apolipoprotein E-deficient mice. The anti-atherosclerotic effect exerts by mechanism(s) other than the regulation of serum MCP-1 and NO concentrations.

Modified Soybean Affects Cholesterol Metabolism in Rats Similarly to a Commercial Cultivar

The consumption of soy protein lowers blood cholesterol in humans and animals. Breeding may alter the physiological effects of soybeans, such as its cholesterol-lowering property. Our hypothesis is that breeding affects the hypocholesterolemic effect of soy by modulating the expression of key hepatic enzymes related to cholesterol and bile acid biosynthesis, as well as altering fecal neutral and acidic steroid excretion. Therefore the aim of this study was to evaluate the effect of a new Brazilian soybean cultivar (UFV-116), lacking lipoxygenases 2 and 3, compared with a commercial cultivar (OCEPAR-19), on 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) and cholesterol 7α-hydroxylase (CYP7A) mRNA expression and fecal steroid output in rats. Thirty-six male rats were fed UFV-116, OCEPAR-19, or casein as the protein source, with or without addition of dietary cholesterol (0.25%). Blood and liver cholesterol, HMGR and CYP7A mRNA abundance, and fecal excretion of steroids were measured. Blood and liver cholesterol levels were lowered by both soybean cultivars, with and without cholesterol, but UFV-116 was more effective when included in the cholesterol-free diet. Both soy diets promoted lower levels of HMGR mRNA, higher levels of CYP7A mRNA, and higher excretion of fecal secondary bile acids. There was higher fecal neutral steroid output when cholesterol was added to all diets. These data show that both soybean cultivars acted similarly in lowering serum and hepatic cholesterol; therefore, breeding did not affect the hypocholesterolemic effect of the new cultivar.

Cholesterol-Lowering Effect of Black Tea Polyphenols, Theaflavins, Theasinensin A and Thearubigins, in Rats Fed High Fat Diet

Rats were fed a high fat diet containing 0.2% black tea polyphenols, theaflavins, theasinensin A or thearubigins for 4 weeks. The hepatic cholesterol concentration was significantly lower in rats fed the theaflavins, theasinensin A or thearubigins diet than in those fed the control diet without black tea polyphenols. Theasinensin A and thearubigins significantly accelerated fecal neutral and acidic steroid excretion, respectively. These results suggest that theasinensin A and thearubigins might induce the hepatic cholesterol-lowering activity through the promotion of fecal steroid excretion.

Soybean Resistant Protein Elevates Fecal Excretion of Cholesterol and Bile Acids and Decreases Hepatic Cholesterol Content in Comparison with Soybean Protein Isolate

The effect of soybean resistant protein (RP) on serum and hepatic cholesterol levels and fecal excretion of steroids was examined. RP decreased cholesterol in the liver, probably due to the stimulated excretion of cholesterol and its metabolites, bile acids. The serum cholesterol level was not different as between RP and other soy-derived proteins.

The role of reverse cholesterol transport in animals and humans and relationship to atherosclerosis

Reverse cholesterol transport (RCT) is a term used to describe the efflux of excess cellular cholesterol from peripheral tissues and its return to the liver for excretion in the bile and ultimately the feces. It is believed to be a critical mechanism by which HDL exert a protective effect on the development of atherosclerosis. In this paradigm, cholesterol is effluxed from arterial macrophages to extracellular HDL-based acceptors through the action of transporters such as ABCA1 and ABCG1. After efflux to HDL, cholesterol may be esterified in the plasma by the enzyme lecithin:cholesterol acyltransferase and is ultimately transported from HDL to the liver, either directly via the scavenger receptor BI or after transfer to apolipoprotein B-containing lipoproteins by the cholesteryl ester transfer protein. Methods for assessing the integrated rate of macrophage RCT in animals have provided insights into the molecular regulation of the process and suggest that the dynamic rate of macrophage RCT is more strongly associated with atherosclerosis than the steady-state plasma concentration of HDL cholesterol. Promotion of macrophage RCT is a potential therapeutic approach to preventing or regressing atherosclerotic vascular disease, but robust measures of RCT in humans will be needed in order to confidently advance RCT-promoting therapies in clinical development.

A Cattle Heart Protein Hydrolysate Ameliorates Hypercholesterolemia Accompanied by Suppression of the Cholesterol Absorption in Rats and Caco-2 Cells

The mechanism for the hypocholesterolemic action of a cattle heart protein hydrolysate (HPH) is clarified. The micellar solubility of cholesterol in vitro was significantly lower in the presence of HPH than in the presence of casein. The suppression of cholesterol uptake by Caco-2 cells was significantly higher in the cholesterol micelles containing HPH than in the cholesterol micelles containing casein. The serum cholesterol concentrations and atherogenic index were significantly lower in the rats fed with HPH than in those fed with casein. The cholesterol absorption measured by [(3)H]-cholesterol was significantly lower by HPH feeding than by casein feeding in rats in vivo accompanying the changes in fecal steroid excretion. Thus, the hypocholesterolemic action of HPH involved the inhibition of jejunal cholesterol absorption. The cattle heart protein hydrolysate ultra-filtrate (HPHU, MW < ca. 1,000 Da peptide fraction) derived from HPH imparted stronger hypocholesterolemic activity than HPH in rats.

Effects of acceptor composition and mechanism of ABCG1-mediated cellular free cholesterol efflux

Among the known mechanisms of reverse cholesterol transport (RCT), ATP binding cassette transporter G1 (ABCG1)-mediated free cholesterol (FC) transport is the most recent and least studied. Here, we have characterized the efficiencies of different acceptors using baby hamster kidney (BHK) cells transfected with human ABCG1 cDNA, which is inducible upon treatment with mifepristone. When normalized on particle number and particle surface area, the acceptor efficiency for FC efflux was as follows: small unilamellar vesicles (SUV)>LDL>reconstituted HDL>HDL2 = HDL3. Based on phospholipid content, the order was reversed. ABCG1 also mediated phospholipid efflux to human serum and HDL3. ABCG1-mediated FC efflux correlated significantly with a number of HDL subfractions and components in serum collected from 25 normolipidemic individuals: apolipoprotein A-II (apoA-II) (r2 = 0.7), apolipoprotein A-I (apoA-I) (r2 = 0.5), HDL-C (r2 = 0.4), HDL-PL (r2 = 0.4), α-2 HDL (r2 = 0.4), and preβ HDL (r2 = 0.2). ABCG1 did not enhance influx of FC or cholesteryl oleyl ether (COE) when cells were incubated with radiolabeled HDL3. ABCG1 expression did not increase the association of HDL3 with cells. Compared with control cells, ABCG1 expression significantly increased the FC pool available for efflux and the rate constant for efflux. In conclusion, composition and particle size determine the acceptor efficiency for ABCG1-mediated efflux. ABCG1 increases cell membrane FC pools and changes its rate of desorption into the aqueous phase without enhancing the association with the acceptor.

167 FAECAL STEROID ANALYSES FOR MONITORING REPRODUCTIVE FUNCTION IN POLAR BEARS (URSUS MARITIMUS)

Although there has been only limited research on polar bears (Ursus maritimus), it is known that they are seasonal breeders that mate in early spring and experience delayed implantation in the fall, giving birth to cubs in early winter. A non-invasive method for monitoring reproductive function in polar bears would facilitate the management of captive and wild polar bears while expanding the physiological database on this species. Longitudinal faecal steroid analyses were conducted on a captive female polar bear (8 years old) to identify suitable enzyme immunoassay (EIA) techniques for monitoring reproduction. Faecal samples were collected over 23 months (July 2006 to June 2008). In January 2007, the female was introduced to an intact male (17 years old) for breeding. For the first 6 months of the study, faecal samples were collected weekly. However, prior to introducing the male, collection frequency was increased to thrice weekly. Animal keeper staff recorded behaviour daily. Steroid hormones were extracted from 0.1 g of lyophilized faeces by mechanically shaking samples overnight in 3 mL 90% v/v ethanol. Samples were centrifuged at 500g for 10 minutes and the supernatant stored at –20°C until assayed. Immunoreactive progesterone (P4), estrogen (E2), progesterone metabolite (PdG) and androgen metabolite concentrations were measured in the faecal samples. Due to the established reproductive seasonality of the species, differences in faecal steroid excretion between breeding (January to June) and non-breeding (July to December) seasons were examined with ANOVA. Values are presented as mean ± SEM dry mass faeces (dmf). Seasonal differences in faecal androgen and PdG excretion were significant (P &lt; 0.05). Baseline androgen metabolite concentrations during the breeding season (124.7 ± 4.8 ng g–1 dmf) were higher (P &lt; 0.05) than during the non-breeding season (105.6 ± 4.7 ng g–1 dmf). Peak androgen metabolite concentrations during the breeding season averaged 1108.8 ± 171.2 ng g–1 dmf and coincided with oestrus behaviour and mating. There was no correlation (P ≥ 0.05) between faecal androgen and E2 patterns. In addition, there were no increases in faecal E2 coinciding with mating behaviour or copulation. Therefore, E2 was deemed unsuitable for oestrous cycle monitoring. Faecal P4 and PdG results were significantly correlated (P &lt; 0.05). Prior to breeding, PdG concentrations were 167.5 ± 22.5 ng g–1 dmf. After a March 2007 breeding, the faecal PdG profile appeared to demonstrate a luteal phase (282.5 ± 25.8 ng g–1 dmf) followed by a PdG spike in mid-October (coinciding with expected implantation) lasting approximately 60 days (1025.5 ± 142.6 ng g–1 dmf). Concentrations of PdG declined precipitously to baseline in early December, but cubs were never observed with the female in her den. These preliminary data suggest that non-invasive faecal steroid analyses can be used to monitor reproductive function in female polar bears.

Faecal steroid excretion in humans is affected by calcium supplementation and shows gender-specific differences

Previous human studies on the effect of dietary calcium supplementation on faecal excretion of bile acids (BA) and faecal water concentrations of animal neutral sterols (NSt, cholesterol and its metabolites) lack detailed information about single BA and NSt. We investigated whether single BA and NSt in faeces and especially in faecal water are affected by calcium supplementation and whether this affects genotoxicity of faecal water. In addition, we differentiated between men and women with regard to the concentrations of BA and NSt in faecal water. Thirty-one healthy volunteers consumed a calcium supplemented bread (1.0 g/day) and a placebo bread, respectively, for 4 weeks in a double-blind, randomised cross-over trial. Faeces were collected quantitatively for 5 days in the last week of each period. NSt and BA were analysed by GC-MS. Due to calcium supplementation faecal concentrations of lithocholic acid (LCA, 14%, P = 0.008), deoxycholic acid (DCA, 19%, P < 0.001) and 12 keto-deoxycholic acid (12 keto DCA, 29%, P = 0.049) significantly increased whereas BA concentrations in faecal water were only marginally affected. In contrast, concentrations of cholesterol (30%, P = 0.020) and its metabolites coprostanol (43%, P = 0.004), coprostanone (36%, P = 0.003), cholestanol (44%, P = 0.001) and cholestenone (32%, P = 0.038) in faecal water significantly decreased. Total NSt concentration in faecal water was found to be significantly higher in women compared to men (P = 0.018). The genotoxicity of faecal water was neither affected by calcium supplementation nor were there gender-specific differences. Dietary calcium supplementation diversely affects BA and NSt in faeces and in faecal water but does not influence the genotoxicity of faecal water in healthy adults.

Characterization of high density lipoprotein particles in familial apolipoprotein A-I deficiency

Our aim was to characterize HDL subspecies and fat-soluble vitamin levels in a kindred with familial apolipoprotein A-I (apoA-I) deficiency. Sequencing of the APOA1 gene revealed a nonsense mutation at codon -2, Q[-2]X, with two documented homozygotes, eight heterozygotes, and two normal subjects in the kindred. Homozygotes presented markedly decreased HDL cholesterol levels, undetectable plasma apoA-1, tuboeruptive and planar xanthomas, mild corneal arcus and opacification, and severe premature coronary artery disease. In both homozygotes, analysis of HDL particles by two-dimensional gel electrophoresis revealed undetectable apoA-I, decreased amounts of small alpha-3 migrating apoA-II particles, and only modestly decreased normal amounts of slow alpha migrating apoA-IV- and apoE-containing HDL, while in the eight heterozygotes, there was loss of large alpha-1 HDL particles. There were no significant decreases in plasma fat-soluble vitamin levels noted in either homozygotes or heterozygotes compared with normal control subjects. Our data indicate that isolated apoA-I deficiency results in marked HDL deficiency with very low apoA-II alpha-3 HDL particles, modest reductions in the separate and distinct plasma apoA-IV and apoE HDL particles, tuboeruptive xanthomas, premature coronary atherosclerosis, and no evidence of fat malabsorption.

麦類に含まれる食物繊維の栄養生理学的研究

Oats and barley are rich in water-soluble dietary fiber which is mainly composed of β-glucan. This study evaluates the nutritional and physiological effects of the water-soluble dietary fiber, cereal gum, in oats and barley from animal and human experiments.Effect of the water-soluble dietary fiber in oats and barley on the lipid metabolism in ratsThe effects of ingested oat and barley gum on the plasma and liver lipid levels were examined in genetically obese and lean Zucker rats. Obese and lean male Zucker rats, aged 6 weeks, were fed for 34 days on a standard diet or on diets corresponding to 2% total dietary fiber. Both the oat and barley gum suppressed the liver lipid accumulation and elevation of the plasma cholesterol level in obese rats. The results of this animal experiment indicate that ingested oat and barley gum ameliorated fatty liver and hypercholesterolemia in obese Zucker rats.Effects of oat and barley gum on the lipid metabolism in ratsThe effect of various amounts of oat and barley gum added to the diet on the plasma and liver lipid levels was examined in cholesterol-fed rats. Male Sprague-Dawley rats, aged 5 weeks, were fed for 9 days on a diet containing the oat or barley gum corresponding to 0%, 1%, 2%, or 4% soluble fiber. The plasma triglyceride, liver cholesterol, and liver triglyceride levels were lower in the rats fed on the diets containing 1-4% oat gum and 2-4% barley gum than in the rats fed on the gum-free diet. The diet containing 4% oat gum increased the fecal excretion of total lipids. The fecal excretion of acidic steroids was higher from the rats fed on the diets containing 2-4% oat gum and 1% barley gum than from the rats fed on the gum-free diet. The results of this experiment indicate that the minimum amounts of oat and barley gum, which acted as lipid-lowering compounds, were respectively 1% and 2% of fiber in the diet.Effect of oatmeal supplementation on the serum cholesterol levels in men with boundary and mild hypercholesterolemiaWe examined the effect of oatmeal containing β-glucan on blood lipids and the safety of its long-term intake in men with boundary and hypercholesterolemia. A total of 48 men with boundary and mild hypercholesterolemia were assigned to three groups. Each group A subject was given four pieces of placebo cookies once a day for 12 weeks, each group B subject was given test oatmeal cookies containing oatmeal at 30g/4 pieces, and each group C subject was given the same cookies containing oatmeal at 45g/4 pieces. The serum total cholesterol level for group C with boundary hypercholesterolemia was significantly lower than that for group A or group C (p<0.05). The results of this human trial indicate that supplementation with oatmeal at 45g/day (1.6g of β-glucan/day) decreased the serum total cholesterol level in men with boundary hypercholesterolemia.Additional human trial with oatmeal porridgeAn additional human trial with oatmeal porridge was examined; each subject in the oatmeal group was given oatmeal porridge containing 45g of oatmeal (1.6g of β-glucan) once a day for 12 weeks, and the control group subjects were given control porridge containing white rice and cellulose as the substitute for oatmeal. The level of serum total cholesterol in the oatmeal group was significantly lower than that in the control group throughout the ingestion period (p<0.05). This additional human trial indicates that oatmeal containing β-glucan could modulate the level of serum total cholesterol.Effect of oatmeal supplementation on the serum cholesterol levels in adults with boundary and mild hypercholesterolemiaThis study examined the effect of oatmeal on the serum cholesterol levels in Japanese adult men and women with boundary and mild hypercholesterolemia. Seventy-four men and nineteen women were randomly assigned to either the placebo or oatmeal group for