Ascorbic acid, HDL, and total plasma cholesterol in the elderly

The relationships between ascorbic acid (plasma and dietary) and plasma HDL cholesterol (HDL-C), total plasma cholesterol (T-C) and T-C:HDL-C ratio were examined in a population of 235 males and 445 females, age 60-98 years. Many known or suspected determinants of HDL-C and T-C, including age, sex, triceps skinfold thickness, fasting blood glucose, alcohol intake, and others, were considered as covariates due to their potential confounding or modifying effects on the relationships under study. The results show that plasma ascorbic acid is significantly (p less than 0.05) correlated with HDL-C (r = 0.09), T-C:HDL-C (r = 0.10), but not with T-C (r = 0.03). There is a strong age interaction with the largest effect of ascorbic acid in the youngest age group studied (60-69 years). The effects of dietary ascorbic acid are similar but slightly reduced in magnitude.     

Dietary single cell protein reduces fatty liver in obese Zucker rats

There is growing evidence that dietary proteins may interfere with lipid metabolism. We therefore examined the effects of feeding obese Zucker rats a single cell protein (SCP) with low ratios of methionine:glycine and lysine:arginine for 6 weeks. SCP feeding reduced the hepatic steatosis and lowered the plasma transaminase levels when compared with casein-fed rats (controls). The fatty acid oxidation was increased in liver mitochondria and peroxisomes, whereas the activities of enzymes involved in lipogenesis and TAG biosynthesis were unaffected. SCP feeding affected the fatty acid composition of liver lipids and plasma, and reduced the mRNA levels of the fatty acid desaturases. The decreased gene expression of stearoyl-CoA desaturase suggested that the fatty acids were directed towards oxidation rather than esterification as TAG. The decreased mRNA levels of VLDL-receptor and lipoprotein lipase in the liver after SCP feeding suggested that the uptake of TAG-rich lipoprotein to the liver was decreased. To conclude, the reduced fatty liver by SCP feeding may be caused by the increased capacity for fatty acid beta-oxidation in the liver, combined with changed fatty acid composition and possibly a reduced hepatic clearance of circulating VLDL. An increased awareness of the effect of dietary proteins on lipid metabolism could be of relevance in future dietary treatment of non-alcoholic fatty liver disease.     

Defatted avocado pulp reduces body weight and total hepatic fat but increases plasma cholesterol in male rats fed diets with cholesterol

The potential use of avocado as a fiber source was evaluated. The total dietary fiber content of fresh avocado fruit of the Ettinger variety was 5.2 g/100 g. Approximately 75% was insoluble, and 25% soluble. The water-holding capacity of dry defatted avocado pulp was similar to that of cellulose, and trypsin inhibitors were not detected. The dietary and metabolic consequences of the avocado pulp were studied in male rats fed normal and hypercholesterolemic diets. Rats consumed semipurified diets containing either avocado pulp as the dietary fiber source or cellulose (control) with or without 10 g/kg cholesterol and 5 g/kg cholic acid. Food consumption and body weight gain were lower in rats fed avocado compared with those fed cellulose. Relative cecum weight was higher in avocado-fed rats. Plasma and hepatic cholesterol levels did not differ in rats fed diets without cholesterol, but plasma cholesterol was greater in avocado-fed than in cellulose-fed rats that consumed cholesterol. Regardless of dietary cholesterol, hepatic total fat levels, as evaluated histologically, but not directly, were lower in avocado-fed rats. These data suggest the presence of an appetite depressant in avocado and that avocado pulp interferes with hepatic fat metabolism.     

Combination of fish oil and fish protein hydrolysate reduces the plasma cholesterol level with a concurrent increase in hepatic cholesterol level in high-fat-fed Wistar rats

ObjectiveThis study investigated the potential additive or synergistic effect of fish oil (FO) and fish protein hydrolysate (FPH) on cholesterol concentration in plasma and the liver.MethodsMale Wistar rats were fed high-fat diets (30% fat, 20% protein, wt/wt) containing FO (5%), FPH (10%), a combination of FO and FPH, or a high-fat control diet. After 7 wk of feeding, the rats were fasted for 12 h before lipid levels in plasma and the liver and hepatic activities of acyl-coenzyme A:cholesterol acyltransferase, 3-hydroxy-3-methylglutaryl coenzyme A reductase, and fatty acid synthase were measured.ResultsThe combination of FO and FPH in the diet profoundly reduced the plasma cholesterol level, mainly due to lowering of high-density lipoprotein cholesterol, whereas the hepatic total cholesterol concentration was elevated compared with control rats and rats fed diets containing FPH or FO alone. The elevated cholesterol concentration in the liver was caused by an increased amount of cholesteryl esters and was in correlation to an increased activity of acyl-coenzyme A:cholesterol acyltransferase. There was a reduced fatty acid synthase activity that could lead to a reduced lipogenesis in the rats fed a combination of FO and FPH.ConclusionA dietary combination of FO and FPH resulted in lower levels of plasma cholesterol and higher levels of hepatic cholesterol compared with dietary FO or FPH alone. Further studies are warranted to confirm whether the hypocholesterolemic effect was due to a reduced secretion of very low-density lipoprotein from the liver.     

Dietary oxidized cholesterol increases expression and activity of antioxidative enzymes and reduces the concentration of glutathione in the liver of rats

An experiment was conducted with rats to investigate the effect of dietary oxidized cholesterol on the antioxidant status. Four groups of male, growing Sprague-Dawley rats received diets containing unoxidized or oxidized cholesterol (5 g/kg diet) with either coconut oil or salmon oil as dietary fat (100 g/kg diet) for 5 weeks. The oxidized cholesterol preparation consisted of 7 g of various cholesterol oxidation products and 93 g of unmodified cholesterol per 100 g preparation. No significant amounts of oxysterols were detected in the unoxidized cholesterol-supplemented diets. As parameters of the antioxidant status activities, mRNA concentrations of several antioxidative enzymes and the concentrations of glutathione were measured. Rats fed the diets containing oxidized cholesterol had significantly higher mRNA concentrations of glutathione peroxidase (p < 0.001) and superoxide dismutase (p < 0.01), a significantly higher activity of glutathione peroxidase (p < 0.001), and significantly lower concentrations of total (p < 0.05) and reduced glutathione (p < 0.01) in the liver than rats fed diets containing unoxidized cholesterol. These effects were independent of the dietary fat. In conclusion, the study suggests that dietary oxidized cholesterol stresses the antioxidant defense system in rats.     

Lupin protein compared to casein lowers the LDL cholesterol:HDL cholesterol-ratio of hypercholesterolemic adults

Background  

Lupin protein had hypocholesterolemic effects in laboratory animals. However, the effect in humans has not been elucidated till now.     

接触二硫化碳大鼠铜水平与血浆LCAT活性的变化及关系的研究

ＳＤ大鼠分别用５ｍｇ／ｍ３和５０ｍｇ／ｍ３ＣＳ２吸入染毒６个月。结果表明：５０ｍｇ／ｍ３ＣＳ２接触组肝铜含量显著减少（Ｐ＜０．０５），血浆ＬＣＡＴ活性显著抑制（Ｐ＜０．０１）。肝铜含量与血浆ＬＣＡＴ活性呈正线性相关（Ｐ＜０．０１）。实验结果提示：ＣＳ２能引起铜代谢紊乱，降低体内铜水平；血浆ＬＣＡＴ是一种铜酶；ＣＳ２可通过干扰铜代谢，从而抑制ＬＣＡＴ活性，引起脂质代谢紊乱。     

Soybean protein hydrolysate improves plasma and liver lipid profiles in rats fed high-cholesterol diet

OBJECTIVE: This investigation attempted to clarify the hypolipidemic effects of non-dialyzed soybean protein hydrolysate (NSPH), which is hydrolyzed by pepsin from soybean acid-precipitated protein (APP), in rats fed a cholesterol-rich diet. METHODS: Forty Sprague-Dawley rats were divided into four groups as the control group (19.7% casein), the APP group (14.7% casein + 5% APP), the NSPH group (14.7% casein + 5% NSPH), and the ISO group (19.7% casein + 0.0013% soy isoflavone). RESULTS: After 12-week experimental period, the APP and NSPH groups had a significant lower plasma total cholesterol, triglycerides, and LDL-cholesterol concentrations compared with the control group. Additionally, the atherosclerosis index in APP and NSPH group had also markedly decreased. Liver cholesterol and triglyceride contents of the APP and NSPH group were significantly lower than those of the control group. There were no different in plasma LDL-C, liver cholesterol and triglycerides between the ISO group and control group. Fecal excretion of neutral steroids and nitrogen compounds was significantly higher in the APP and NSPH groups than that in the control group. An in vitro study also showed that NSPH, compared with casein, obviously decreased cholesterol micellar solubility. CONCLUSION: These results suggested that NSPH may decrease lipid accumulation in the liver and have a hypolipidemic effect by enhancing excretion and inhibiting absorption of lipids.     

Macadamia nut consumption lowers plasma total and LDL cholesterol levels in hypercholesterolemic men

This study was conducted to assess the cholesterol-lowering potential of macadamia nuts. Seventeen hypercholesterolemic men (mean age 54 y) were given macadamia nuts (40-90 g/d), equivalent to 15% energy intake, for 4 wk. Plasma total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides and homocysteine concentrations and the fatty acid composition of plasma lipids were determined before and after treatment. Plasma MUFA 16:1(n-7), 18:1(n-7) and 20:1(n-9) were elevated after intervention with macadamia nuts. Plasma (n-6) and (n-3) PUFA concentrations were unaffected by macadamia nut consumption. Plasma total cholesterol and LDL cholesterol concentrations decreased by 3.0 and 5.3%, respectively, and HDL cholesterol levels increased by 7.9% in hypercholesterolemic men after macadamia nut consumption. Plasma triglyceride and homocysteine concentrations were not affected by treatment. Macadamia nut consumption was associated with a significant increase in the relative intake of MUFA and a reduced relative intake of saturated fatty acids and PUFA. This study demonstrates that macadamia nut consumption as part of a healthy diet favorably modifies the plasma lipid profile in hypercholesterolemic men despite their diet being high in fat.     

Naringin time-dependently lowers hepatic cholesterol biosynthesis and plasma cholesterol in rats fed high-fat and high-cholesterol diet

The flavonoid naringin was investigated for its differential effects on hepatic cholesterol regulation when supplemented for 3 weeks and 6 weeks. Sprague-Dawley rats were fed a high-fat and high-cholesterol diet with or without 0.02% naringin supplement for 3 or 6 weeks. Supplementation with naringin resulted in a significant decrease in the plasma cholesterol and triglyceride concentrations in the 6-week trial. Although high-density lipoprotein (HDL)-cholesterol was not altered in either trial, the HDL-cholesterol/total cholesterol ratio (in percent) was significantly higher, and the atherogenic index was significantly lower in the naringin-supplemented groups in the 6-week trial. The hepatic cholesterol content was also lowered by naringin supplementation only in the 6-week trial. The hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity was lower in the rats supplemented with naringin for 6 weeks, while the hepatic acyl-coenzyme A:cholesterol acyltransferase activity was lower in both the 3-week and 6-week trials. Results indicate that supplementation with naringin for 3 weeks did not exhibit a hypolipidemic effect when given with a HFHC diet. Naringin can, however, be beneficial for lowering hepatic cholesterol biosynthesis and levels of plasma lipids when supplemented for 6 weeks in this animal model.     

Dietary chitosan enhances hepatic CYP7A1 activity and reduces plasma and liver cholesterol concentrations in diet-induced hypercholesterolemia in rats

The present study was performed to elucidate the hypocholesterolemic action of chitosan on the diet-induced hypercholesterolemia in rats. Male Sprague-Dawley rats (n=24) were fed with chitosan-free diet (Control), diets containing 2% or 5% chitosan for 4 weeks. Hypercholesterolemia was induced by adding 1% cholesterol and 0.5% cholic acid to all diets. Body weight gain and food intake of rats did not differ among the groups. The chitosan treated groups showed significant improvement in the plasma concentration of total cholesterol and LDL-cholesterol compared to the control group (p<0.05). Also, the chitosan treated groups decreased the liver concentration of total lipid and total cholesterol compared to the control group (p<0.05). The activity of hepatic cholesterol 7α-hydroxylase (CYP7A1), the rate-limiting enzyme in the conversion of cholesterol to bile acids, was increased by 123% and 165% for the 2% or 5% chitosan diets, respectively. These findings suggest that enhancement of hepatic CYP7A1 activity may be a mechanism, which can partially account for the hypocholesterolemic effect of dietary chitosan in cholesterol metabolism.     

A cooperative interaction between soy protein and its isoflavone-enriched fraction lowers hepatic lipids in male obese Zucker rats and reduces blood platelet sensitivity in male Sprague-Dawley rats

Soy protein diets lower plasma cholesterol in hyperlipoproteinemic human subjects, as well as in animal models. We fed 7-wk-old male obese (fa/fa) and lean Zucker rats a modified AIN-76 diet (20 g protein/kg diet) containing casein (C), low isoflavone soy protein (38 mg isoflavones/kg diet; LI), or high isoflavone soy protein (578 mg isoflavones/kg diet; HI) for 70 d. In obese rats, plasma total cholesterol was 21 and 29% lower in the LI and HI groups, respectively, than in the C group (P: 相似文献   

Plant sterol ester-enriched spread lowers plasma total and LDL cholesterol in children with familial hypercholesterolemia

BACKGROUND: Naturally occurring plant sterol esters (SEs) favorably affect serum cholesterol concentrations in humans and could aid in the treatment of children with familial hypercholesterolemia (FH). OBJECTIVE: We studied the effect of SE-enriched spread on serum lipids, lipoproteins, carotenoids, fat-soluble vitamins, and physiologic variables in children with FH aged 7-12 y. DESIGN: In a randomized, double-blind crossover study comprising two 8-wk interventions, 38 children with FH consumed 18.2 +/- 1.5 g SE spread/d, corresponding to 1.60 +/- 0.13 g SEs, or a control spread. Blood samples were analyzed at the start and end of each diet period. RESULTS: Plasma LDL-cholesterol concentrations decreased by 10.2% (P = 0.003) during the SE period compared with the control period. Total cholesterol and apolipoprotein B concentrations were reduced by 7.4% (P = 0.007 and P = 0.020, respectively) during the SE period. No changes were observed in HDL cholesterol, triacylglycerol, or apolipoprotein A-I. Serum concentration of lipid-adjusted lycopene decreased by 8.1% (P = 0.015) in the SE period, with no changes in the other carotenoids. Lipid-adjusted retinol and alpha-tocopherol concentrations increased by 15.6% (P < 0.001) and 7.1% (P = 0.027), respectively. There was an increase (16.8%, P = 0.04) in alanine transaminase in the SE period, but this was explained by a significantly lower starting concentration in the SE period than in the control period. The children consumed a recommended American Heart Association Step I diet during both intervention periods. CONCLUSION: A daily intake of 1.6 g SEs induces an additional reduction in LDL-cholesterol concentrations in children with FH consuming a recommended diet.     

Risk of nosocomial infections and effects of total cholesterol,HDL cholesterol in surgical patients

BACKGROUND AND AIMS: Changes of lipoprotein pattern in plasma occur in many acute infections. The aim of this study was to analyse the role of total cholesterol and HDL cholesterol in postsurgical patients with nosocomial infection. METHODS: Four hundred and eighteen patients admitted to our department and operated on for various diseases are included in this prospective study. Various conventional risk factors for nosocomial infections were recorded. Biochemical parameters with plasma total cholesterol and HDL-cholesterol (HDL-C) levels were measured. RESULTS: In our study, the most frequent infection was surgical site infection. There was an increased association between low HDL-C level and nosocomial infections such as surgical site and pulmonary infections. HDL levels may be used as predictive parameter for surgical nosocomial infections. CONCLUSIONS: HDL-C levels seem to be one of the risk factors for postoperative nosocomial infection. Although total cholesterol level was not significantly increased, it may be also associated with the infection risk. Screening of lipoprotein pattern in patients undergoing operation may be useful for ascertaining of risk for nosocomial infection.     

Cholinesterase activity in the serum and liver of Zucker fat rats and controls

Serum and liver cholinesterase activity was observed to be significantly higher in chow fed Zucker fat rats than in chow fed lean controls. Similarly, serum triglycerides and insulin showed significantly higher levels in the fat rats compared to the controls. In contrast, no significant difference was observed for adipose tissue cholinesterase, serum glucose and cholesterol.Correlation analyses revealed a positive correlation between serum and liver cholinesterase activity when data were combined from both obese and lean rats indicating liver as the possible source of cholinesterase. Serum cholinesterase also correlated positively with triglycerides, body weight and food intake. Food intake also showed a strong positive correlation with serum triglycerides and body weight.     

The Troms? Heart Study: food habits, serum total cholesterol, HDL cholesterol, and triglycerides

Associations between food habits and total serum cholesterol, high density lipoprotein (HDL) cholesterol, and serum triglycerides were examined in 7,410 men and 7,257 women in Troms?, Norway, following a screening in 1979-1980. High body mass index was associated with high serum cholesterol, high triglycerides, and low HDL cholesterol. Positive associations were observed between high serum cholesterol and high coffee consumption, use of butter or hard margarine, not selecting low-fat milk, and low bread consumption. The HDL cholesterol level was virtually independent of the dietary items recorded. Use of low-fat milk and frequent use of fish dishes for dinner seemed to be related to low serum triglyceride levels.     

Trans fat intake lowers total cholesterol and high-density lipoprotein cholesterol levels without changing insulin sensitivity index in Wistar rats

Epidemiologic studies have demonstrated that trans fat intake increases the risk of some chronic diseases. We hypothesize that trans fat intake would increase the risk of cardiovascular disease and type 2 diabetes mellitus by changing the lipid profile in plasma, the secretion of adipokines in adipose tissue, and the insulin sensitivity. Accordingly, the major objective of present study was to investigate the effect of dietary intake of trans fat on lipid profile, insulin sensitivity, and adipokine levels in plasma. Two groups of Wistar rats were fed a diet containing 4.5% trans fat or a control diet containing no trans fat for 16 weeks. Fasting glucose level was monitored every 2 weeks. At the end of feeding experiment, blood, heart, kidney, liver, omental adipose tissue, and semitendinosus muscle were collected. The trans fat content in organs, lipid profile, adipokine, insulin, and glucose levels in plasma were analyzed. The trans fat content in adipose tissue, heart, kidney, liver, and muscle of rats fed trans fat were 169.9, 0.6, 1.2, 1.7, and 2.5 mg/g samples, respectively. The trans fat content in these organs contributed to 15.9%, 1.2%, 2.3%, 4.3%, and 6.1% of the total fat, respectively. The plasma glucose level, insulin level, and insulin sensitivity index were not significantly different between the trans fat and control groups. The results indicated that trans fat intake might not be related to insulin resistance. However, lipid profile and plasma adipokine levels were significantly changed after trans fat feeding. The trans fat fed group showed significantly lower total cholesterol and high-density lipoprotein cholesterol levels than the control group. The decreased high-density lipoprotein cholesterol level may indicate the detrimental effect of trans fat intake on lipid profile. Adiponectin and resistin levels were significantly higher in the trans fat group than the control group. Leptin levels were significantly lower in the trans fat group than the control group. The results indicated that dietary intake of trans fat can significantly change the adipokine levels, but the possible links between adipokine level change caused by trans fat intake and metabolic effects of this change need further investigations.     

Dietary orotic acid increases 1 ,2-diacylglycerol level and lowers superoxide dismutase activity in rat liver

The effects of the dietary addition of orotic acid were studied on lipid levels in the rat liver and serum, 1,2-diacylglycerol levels in some organs, activities of antioxidant liver enzymes (superoxide dismutase, glutathione peroxidase, and catalase), and serum enzyme activities (ornithine carbamoyltransferase and alanine aminotransferase), after feeding for 0, 7, 14, and 21 d, respectively. Rats on the orotic acid diet accumulated more liver total lipids, triacylglycerol, and phospholipids than those on the basal diet. However, the levels of serum triacylglycerol and phospholipids of those rats were markedly decreased after 7, 14, and 21 d on the diet. Dietary orotic acid increased the 1,2-diacylglycerol levels in the liver of rats fed for 14 or 21 d, but not in the ileum of small intestine, vastus lateralis muscle, and heart. The addition of orotic acid lowered the activities of liver total and Cu,Zn-superoxide dismutase after feeding for 7, 14, and 21 d. The serum ornithine carbamoyltransferase activity after 14, and 21 d and that of serum alanine aminotransferase after 7, 14, and 21 d were increased. These data suggested that the increase in the activities of serum enzymes tested may result from liver damage induced by the marked accumulation of liver lipids and possibly from the increased superoxide anion because of the decreased activities of hepatic superoxide dismutase by orotic acid feeding.     

Chinese soft-shelled turtle egg powder lowers serum cholesterol, increases faecal neutral steroids and bile acid excretion, and up-regulates liver cytochrome P450 mRNA level in rats

The aim of the present study was to investigate the effect of Chinese soft-shelled turtle whole egg powder (TE) on cholesterol metabolism in Sprague-Dawley rats to determine whether it has a cholesterol-lowering effect. Forty male Sprague-Dawley rats were fed a high-fat diet supplemented with TE (0, 0.75, 1.50 or 3.00 g/kg body weight) administrated by gavage for 24 weeks. Serum total cholesterol (TC), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C) and faecal total bile acids levels were determined by enzymatic methods. Faecal steroid concentrations were measured by GC. Means and standard deviations were calculated where appropriate for values, and the data were tested by one-way ANOVA. After 24 weeks of feeding a high-fat diet with TE supplementation, serum TC and LDL-C levels, liver cholesterol and liver lipid levels were reduced in rats. TE supplementation did not affect the faecal output, but significantly increased steroid concentrations in faeces, indicating increased steroids excretion. The faecal bile acid excretion was also increased as evidence by elevated mRNA level of liver cytochrome P450, family 7, subfamily A, polypeptide 1. Our results demonstrated that the TE does have a cholesterol-lowering effect by increasing the excretion of total bile acids and neutral steroids.