Effect of onion and beet on plasma and liver lipids, platelet aggregation, and erythrocyte Na efflux in simvastatin treated hypercholesterolmic rats

This study was purposed to investigate the effect of onion or beet on plasma and liver lipids, erythrocyte Na efflux channels and platelet aggregation in simvastatin (SIM) treated hypercholesterolemic rats. Forty Sprague Dawley rats were divided into four groups and fed 0.5% cholesterol based diets containing 2 mg/kg BW simvastatin or simvastatin with 5% onion or beet powder. Plasma total cholesterol was significantly increased in SIM group compared with the control (p<0.01), and the elevated plasma total cholesterol of SIM group was significantly decreased in SIM-onion and SIM-beet groups (p<0.05). HDL-cholesterol in SIM-beet group was significantly increased compared with other groups (p<0.05). Platelet aggregation in both the maximum and initial slope was significantly decreased in SIM group compared with SIM-onion group (p<0.05). Na-K ATPase was significantly decreased in SIM group compared with the control, SIM-onion and SIM-beet groups (p<0.05). Na passive leak was significantly increased in all groups treated with SIM compared with the control (p<0.05). The total Na efflux was decreased in SIM group and increased in SIM-onion group and the difference between these two groups was significant (p<0.05). There was no difference in intracellular Na among groups. In present study, simvastatin, a HMG CoA reductase inhibitor at dose of 2mg/kg BW/day rather increased plasma total cholesterol in rats, inferring that the action mechanism of simvastatin on cholesterol metabolism differ between rat and human. Onion and beet play favorable roles in cardiovascular system by restoring the reduced Na efflux through Na-K ATPase and Na-K cotransport in SIM treated rats.     

Effect of coenzyme Q10 and Ardisia japonica Blume on plasma and liver lipids, platelet aggregation, and erythrocyte Na efflux channels in simvastatin-treated guinea pigs

Forty guinea pigs were divided into four groups and fed 0.04% cholesterol based control diet, plus 0.05% simvastatin, and statin plus 0.1% CoQ10 or 10% Ardisia Japonica Blume (AJB) leave powder for 4 weeks. Plasma total cholesterol levels decreased significantly in all groups fed the statin-containing diet compared with that in guinea pigs fed the control diet (P < 0.01). Plasma and liver triglycerides decreased significantly in the statin plus CoQ10 group compared with those in the control (both P < 0.05). Maximum platelet aggregation was significantly higher in the statin plus CoQ10 group than that in the other groups (P < 0.05). Na-K ATPase activity increased in the statin group and decreased in the statin plus CoQ10 group (P < 0.01). Na-K co-transport and Na passive transport decreased significantly in the control group compared with those in the other groups (both P < 0.05). Intracellular Na was highest in the statin group and lowest in the statin plus CoQ10 group and was correlated with Na-K ATPase activity. Thiobarbituric acid reactive substance production in platelet-rich plasma and liver tended to decrease in the statin plus CoQ10 group compared with those in the other groups. Plasma glutamic-pyruvic transaminase and glutamic-oxaloacetic transaminase increased significantly in the statin group compared with those in the control (P < 0.05). These result suggest that antioxidant rich AJB did not have positive effects on cardiovascular disease parameters. The statin plus CoQ10 seemed to decrease cholesterol more efficiently than that of statin alone.     

Effects of green tea or Sasa quelpaertensis bamboo leaves on plasma and liver lipids, erythrocyte Na efflux, and platelet aggregation in ovariectomized rats

This study was conducted to investigate the effects of Sasa quelpaertensis bamboo and green tea on plasma and liver lipids, platelet aggregation, and erythrocyte membrane Na channels in ovariectomized (OVX) rats. Thirty female rats were OVX, and ten female rats were sham-operated at the age of 6 weeks. The rats were divided into four groups at the age of 10 weeks and fed the experiment diets: sham-control, OVX-control, OVX-bamboo leaves (10%), or OVX-green tea leaves (10%) for four weeks. Final body weight increased significantly in the OVX groups compared with that in the sham-control, whereas body weight in the OVX-green tea group decreased significantly compared with that in the OVX-control (P < 0.01). High density lipoprotein (HDL)-cholesterol level decreased in all OVX groups compared with that in the sham-control rats (P < 0.05) but without a difference in plasma total cholesterol. Plasma triglycerides in the OVX-green tea group were significantly lower than those in the sham-control or OVX-control group (P < 0.05). Liver triglycerides increased significantly in the OVX-control compared with those in the sham-control (P < 0.01) but decreased significantly in the OVX-green tea group compared with those in the OVX-control or OVX-bamboo group (P < 0.01). Platelet aggregation in both maximum and initial slope tended to be lower in all OVX rats compared with that in the sham-control rats but was not significantly different. Na-K ATPase tended to increase and Na-K cotransport tended to decrease following ovariectomy. Na-K ATPase decreased significantly in the OVX-green tea group compared with that in the OVX-control group (P < 0.01), and Na-K cotransport increased significantly in the OVX-bamboo and OVX-green tea groups compared with that in the OVX-control (P < 0.05). Femoral bone mineral density tended to be lower in OVX rats than that in the sham-control, whereas the green tea and bamboo leaves groups recovered bone density to some extent. The results show that ovariectomy caused an increase in body weight and liver triglycerides, and that green tea was effective for lowering body weight and triglycerides in OVX rats. Ovariectomy induced an increase in Na efflux via Na-K ATPase and a decrease in Na efflux via Na-K cotransport. Furthermore, consumption of green tea and bamboo leaves affected Na efflux channels, controlling electrolyte and body water balance.     

Effect of Coenzyme Q10 and green tea on plasma and liver lipids, platelet aggregation, TBARS production and erythrocyte Na leak in simvastatin treated hypercholesterolmic rats

This study was conducted to investigate the hypocholesterolemic effect of simvastatin (30 mg/kg BW) and antioxidant effect of coenzyme Q10 (CoQ10, 15 mg/kg BW) or green tea (5%) on erythrocyte Na leak, platelet aggregation and TBARS production in hypercholesterolemic rats treated with statin. Food efficiency ratio (FER, ADG/ADFI) was decreased in statin group and increased in green tea group, and the difference between these two groups was significant (p<0.05). Plasma total cholesterol was somewhat increased in all groups with statin compared with control. Plasma triglyceride was decreased in statin group and increased in groups of CoQ10 and green tea, and the difference between groups of statin and green tea was significant (p<0.05). Liver total cholesterol was not different between the control and statin group, but was significantly decreased in the group with green tea compared with other groups (p<0.05). Liver triglyceride was decreased in groups of statin and green tea compared with the control, and the difference between groups of the control and green tea was significant (p<0.05). Platelet aggregation of both the initial slope and the maximum was not significantly different, but the group with green tea tended to be higher in initial slope and lower in the maximum. Intracellular Na of group with green tea was significantly higher than the control or statin group (p<0.05). Na leak in intact cells was significantly decreased in the statin group compared with the control (p<0.05). Na leak in AAPH treated cells was also significantly reduced in the statin group compared with groups of the control and CoQ10 (p<0.05). TBARS production in platelet rich plasma was significantly decreased in the groups with CoQ10 and green tea compared with the control and statin groups (p<0.05). TBARS of liver was significantly decreased in the group with green tea compared with the statin group (p<0.05). In the present study, even a high dose of statin did not show a cholesterol lowering effect, therefore depletion of CoQ10 following statin treatment in rats is not clear. More clinical studies are needed for therapeutic use of CoQ10 as an antioxidant in prevention of degenerative diseases independent of statin therapy.     

Dietary taurine or glycine supplementation reduces plasma and liver cholesterol and triglyceride concentrations in rats fed a cholesterol-free diet

The effects of dietary supplementation of taurine or glycine, the two amino acids involved in bile acid conjugation in the liver, on plasma and hepatic lipid concentrations were evaluated in rats fed a cholesterol-free diet. Three groups of male rats (140150g) were fed a cholesterol-free diet (CFD), a taurine-supplemented diet (TSD; CFD + 1.5% taurine) or a glycine-supplemented diet (GSD; CFD + 1.5% glycine) for 5 weeks. There was no significant difference in organ weights and cumulative body weight gain between groups at the end of the experimental period. Plasma triglyceride level was significantly lower in rats fed the TSD (53% decrease, P<0.001) compared to those fed the CFD. Both TSD and GSD significantly lowered the plasma levels of total cholesterol (40% decrease in TSD, p<0.001 and 27% decrease in GSD, p<0.001, respectively) and LDL-plus VLDL-cholesterol (50% decrease in TSD, p<0.05 and 39% decrease in GSD, p<0.01, respectively) compared to the values for CFD. Liver cholesterol concentration was not significantly influenced by the dietary supplementation of taurine or glycine. However, both TSD and GSD showed significantly lower hepatic triglyceride concentrations (43% and 53% decreases in TSD and GSD, p<0.001, respectively), and elevated hepatic free fatty acid levels (77% increases in both groups, p<0.001) compared to the values for CFD. These results suggest the possible roles of dietary taurine or glycine as hypocholesterolemic and/or hypotriglyceridemic agents.     

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.     

Effects of dietary taurine supplementation on plasma and liver lipids in OVX rats fed calcium-deficient diet

Taurine supplementation has been shown to have an effect on lowering blood lipids in ovariectomized (OVX) rats. It therefore seemed desirable to find out whether the beneficial effect of taurine on OVX rats fed calcium-deficient diet could also be reproduced. Forty female Sprague-Dawley rats were divided into two groups. One group was OVX and the other group received a sham operation (Sham). Each rat group was further divided into the control diet and the taurine supplemented (2.0 g/100 g diet) diet group. All rats were fed on calcium-deficient diet and deionized water ad libitum for 6 weeks. Plasma and liver lipids were determined by using commercial kits. LDL-cholesterol concentrations were estimated with the equation of Friedewald et al. (1972). There were no significant differences in body weight gain and food intake between the control and taurine group within Sham and OVX groups, but body weight gain, food intake, and food efficiency ratio was higher in the OVX group. Concentrations of plasma total cholesterol, triglyceride, LDL-cholesterol were significantly lower in the taurine fed group of OVX rats fed Ca deficient diet, while HDL-cholesterol concentration was increased in the taurine fed group. Therefore, in this study, we examined whether taurine also prevented hypercholesterolemia induced by ovarian hormone deficiency in ovariectomized rats when they were fed a calcium-deficient diet. These results indicate that taurine may have some beneficial effects on hypercholesterolemia and hypertriglyceridemia in OVX rats fed calcium-deficient diet.     

Effect of Chlorella vulgaris on lipid metabolism in Wistar rats fed high fat diet

This study was performed to investigate effects of Chlorella vulgaris on lipid metabolism in rats fed high fat diet. Sixty 6-week-old male Wistar rats were divided into two groups; normal diet group and high fat diet group, then the rats in each group were further divided into three subgroups and fed 0%, 5% and 10% (w/w) chlorella-containing diets, respectively, and raised for 9 weeks. Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity and total protein and albumin concentration were not different among groups. Serum total lipids and liver TG concentration were significantly lower in 5% and 10% chlorella groups than 0% chlorella group in high fat diet groups (p<0.05). Serum TG, serum total cholesterol, liver total lipid and liver total cholesterol concentrations were significantly lower in 10% chlorella groups than 0% chlorella group in high fat diet groups (p<0.05). Fecal total lipid, TG and total cholesterol excretions were significantly higher in 5% and 10% chlorella groups than 0% chlorella groups in normal diet and high fat diet groups, respectively (p<0.05). These results suggest that Chlorella vulgaris is effective for prevention of dyslipidemia which may be due to the modulation of lipid metabolism and increased fecal excretion of lipid.     

补充牛磺酸对正常大鼠脂代谢的影响

为研究不同牛磺酸水平对正常大鼠血脂的影响 ,将 40只断乳SD大鼠用基础饲料喂养一周后 ,按体重和血浆总胆固醇均衡的原则分为 4组 ,对照组进食正常饲料 ,其余 3组分别在基础饲料的基础上添加不同水平 (6、1.35和 3g kg饲料 )的牛磺酸 ;实验 5周后 ,观察牛磺酸对大鼠血脂的影响。结果表明 ,与正常对照组相比 ,不同剂量的牛磺酸均可显著影响大鼠血浆脂质水平 ;6g kg牛磺酸降低血清总胆固醇、低密度脂蛋白胆固醇效果最明显 ,13.5g kg牛磺酸可显著降低血清甘油三酯、载脂蛋白 B水平 ,促进粪胆汁酸排泄 ;30g kg牛磺酸对降低大鼠肝脏总胆固醇、升高血清载脂蛋白效果较好。     

Taurine prevents hypercholesterolemia in ovariectomized rats fed corn oil but not in those fed coconut oil

We studied whether the type of dietary fatty acid influences the preventive effect of taurine on the ovarian hormone deficiency-induced increase in plasma cholesterol concentration in 6-mo-old ovariectomized rats. Rats were fed one of the following four diets for 28 d: purified diets based on corn oil, which is rich in linoleic acid, with or with out taurine (50 g/kg) or purified diets based on coconut oil, which is rich in lauric and myristic acids, with or without taurine. Body mass gain, food intake, liver weight and plasma apolipoprotein (apo) A-I, apo B, LDL and VLDL concentrations were not affected by the diets. On the other hand, taurine lowered the plasma total cholesterol concentration (P < 0.02) in rats fed corn oil, but not in those fed coconut oil. In rats fed both types of oils, taurine increased the LDL receptor mRNA level (P < 0.01), hepatic cholesterol 7alpha-hydroxylase activity (P < 0.01) and fecal bile acid excretion (P < 0.01). Taurine increased the HMG-CoA reductase mRNA level (P < 0.02) in the liver of rats fed coconut oil, but not in those fed corn oil. Taurine increased liver total lipid (P < 0.05) and triglyceride (P < 0.05) concentrations in rats fed corn oil, but not in those fed coconut oil. These results indicate that the effect of taurine on ovarian hormone deficiency-induced changes in cholesterol metabolism is influenced by the type of dietary fatty acids.     

大鼠饲料中补充牛磺酸对血、肝胆固醇水平的影响

本文采用半合成低胆固醇或高胆固醇饲料研究添加不同剂量的牛磺酸对wistar大鼠血及肝中胆固醇水平的影响。结果表明:牛磺酸对大鼠血胆固醇水平的作用与实验期长短和饲料中添加牛磺酸的含量有关。在第三周末,实验组大鼠血胆固醇、血甘油三酯及肝胆固醇水平显著低于对照组,但肝脂肪总量无明显变化;高胆固醇饲料中添加牛磺酸后,大鼠血清高密度脂蛋白胆固醇水平有升高趋势,致动脉粥样硬化指数明显改善,提示牛磺酸可能有促进肝胆固醇分解并对预防动脉粥样硬化的发生有作用。     

Hypoglycemic and hypolipidemic effects of Saururus chinensis Baill in streptozotocin-induced diabetic rats

Saururus chinensis Baill was reported to inhibit α-glucosidase in vitro and flatten postprandial increase in blood glucose in streptozotocin (STZ)-induced diabetic rats. We studied the effect of chronic consumption of S. chinensis Baill on blood glucose and lipid profile in STZ-induced diabetic male rats fed high fat diet. Male rats weighing 100-120 g were fed 30% fat diet with and without 10% freeze-dried leaves of S. chinensis Baill for 7 weeks after 1 week of adaptation. The rats were rendered diabetic by intravenous injection of STZ (60 mg/kg) after 6-week feeding of the assigned diets. At 1 week after the injection, the rats were sacrificed after an overnight fast. Plasma glucose (380.2 ± 14.4 mg/dL), total cholesterol (93.9 ± 7.9 mg/dL) and triglyceride levels (123.6 ± 7.5 mg/dL) of the S. chinensis Baill group were significantly lower than those of the control group (418.1 ± 12.0 mg/dL, 119.9 ± 9.4 mg/dL, 152.0 ± 10.3 mg/dL, respectively, p<0.05). Chronic consumption of S. chinesis Baill significantly decreased maltase activity of the small intestinal mucosa (120.1 ± 8.7 U/g protein) compared with the control group (96.8 ± 7.0 U/g protein, p<0.05). These results suggest that S. chinensis Baill have hypoglycemic and hypolipidemic effects by inhibiting α-glucosidase activity in the animal model of diabetes mellitus.     

The effect of taurine on plasma cholesterol concentration in genetic type 2 diabetic GK rats

The purpose of this study is to investigate the effect of taurine on the plasma cholesterol concentration in genetic type 2 diabetic rats fed cholesterol-free or high-cholesterol diets. Diabetic rats (GK male rats) and normal rats (Wistar male rats) were fed either a cholesterol-free or cholesterol-enriched (1% cholesterol + 0.25% sodium cholate) diet supplemented with or without 3% taurine for 21 or 14 d. Compared to the normal rats, diabetic rats showed a high glucose concentration in their blood and plasma, but it was not affected by taurine feeding. The plasma insulin concentration was higher in the diabetic rats than in the normal rats. At the start of the experiment, the plasma cholesterol concentration was significantly higher in the diabetic rats than in the normal rats. Taurine did not affect the plasma cholesterol level in rats fed the cholesterol-free diet. However, taurine feeding significantly increased the plasma HDL-cholesterol concentration in the diabetic rats fed the cholesterol-free diet. In both the diabetic and normal rats fed the cholesterol diet, the plasma cholesterol concentration was significantly lower in rats fed the diet supplemented with taurine than in the rats fed the control diet. It was concluded that taurine has a hypocholesterolemic effect in both diabetic and normal rats fed diets containing cholesterol. Moreover, these results suggest that taurine seems to affect the HDL-cholesterol metabolism in diabetic rats fed a cholesterol-free diet.     

Zinc deficiency negatively affects alkaline phosphatase and the concentration of Ca, Mg and P in rats

Zn is an essential nutrient that is required in humans and animals for many physiological functions, including immune and antioxidant function, growth, and reproduction. The present study evaluated whether Zn deficiency would negatively affect bone-related enzyme, ALP, and other bone-related minerals (Ca, P and Mg) in rats. Thirty Sprague Dawley rats were assigned to one of the three different Zn dietary groups, such as Zn adequate (ZA, 35 mg/kg), pair fed (PF, 35 mg/kg), Zn deficient (ZD, 1 mg/kg) diet, and fed for 10 weeks. Food intake and body weight were measured daily and weekly, respectively. ALP was measured by spectrophotometry and mineral contents were measured by inductively coupled plasma-mass spectrophotometer (ICP-MS). Zn deficient rats showed decreased food intake and body weight compared with Zn adequate rats (p<0.05). Zn deficiency reduced ALP activity in blood (RBC, plasma) and the tissues (liver, kidney and small intestine) (p<0.05). Also, Zn deficiency reduced mineral concentrations in rat tissues (Ca for muscle and liver, and Mg for muscle and liver) (p<0.05). The study results imply the requirement of proper Zn nurture for maintaining bone growth and formation.     

Dietary taurine alters ascorbic acid metabolism in rats fed diets containing polychlorinated biphenyls

The effect of dietary taurine on ascorbic acid metabolism and hepatic drug-metabolizing enzymes was investigated in rats fed diets containing polychlorinated biphenyls (PCB) to determine whether taurine has an adaptive and protective function in xenobiotic-treated animals. Young male Wistar rats (60 g) were fed diets containing 0 or 0.2 g/kg diet PCB with or without 30 g/kg diet of taurine for 14 d. The rats fed the PCB-containing diets had greater liver weight, higher ascorbic acid concentrations in the liver and spleen and greater hepatic cytochrome P-450 contents than control rats that were not treated with PCB (P < 0.01). In PCB-fed rats, urinary ascorbic acid excretion was enhanced, and serum cholesterol concentration (especially HDL-cholesterol) was significantly elevated compared with those in control rats. Dietary taurine significantly potentiated the increases in the urinary excretion of ascorbic acid and the rise in the levels of cytochrome P-450 which were caused by PCB treatment. On the other hand, the supplementation of taurine to control diet did not alter these variables. Taurine may enhance the hepatic drug-metabolizing systems, leading to the stimulation of the ascorbic acid metabolism in rats fed diets containing PCB.     

Plasma taurine concentrations increase after enteral glutamine supplementation in trauma patients and stressed rats

BACKGROUND: Taurine is a unique amino acid with antioxidant and osmolytic properties. Glutamine serves as the preferred fuel for the gut, liver, and immune cells and as a precursor for antioxidants. Trauma patients have low glutamine concentrations. OBJECTIVES: We investigated the effect of glutamine-enriched enteral nutrition on plasma taurine concentrations in patients with severe trauma (injury severity score >20). Additionally, plasma taurine concentrations and organ fluxes were studied in a stressed rat model. DESIGN: Twenty-nine patients with multiple trauma received glutamine-enriched nutrition and 31 patients received isocaloric, isonitrogenous control solution for 5 d. Plasma taurine and glutamine concentrations were measured. Male Wistar rats (250-300 g) received a glutamine-enriched diet (12%, by wt) or a control solution for 2 wk. Plasma taurine concentrations were measured. Taurine fluxes and fractional extraction rates in the liver, kidneys, and gut were assessed with a radioactive microsphere technique. RESULTS: Both patient groups had low taurine concentrations on day 1. From day 3 onward, the glutamine-fed patients had significantly higher taurine concentrations. Rats fed a glutamine-enriched diet had significantly higher plasma taurine concentrations than did the controls. A high taurine uptake was found in the liver, kidneys, and gut of the glutamine-fed rats. Fractional extraction rates were not significantly different between the rat groups. CONCLUSIONS: Glutamine enrichment increases plasma taurine in trauma patients and in stressed rats. Because of increased availability, organ fluxes showed a higher taurine uptake in the liver, kidneys, and gut. The reduction in morbidity with glutamine enrichment could be explained in part by increased taurine availability.     

The effect of taurine on the cholesterol metabolism in rats fed diets supplemented with cholestyramine or high amounts of bile acid

The effects of taurine on serum cholesterol levels and hepatic cholesterol 7alpha-hydroxylase activity (CYP7A1) were studied in rats fed cholestyramine or high amounts of sodium cholate in order to alter the intestinal pool of bile acids. Rats were fed a diet supplemented with 1% cholesterol and 0.25% sodium cholate (high cholesterol, control; C), and C supplemented with 4% cholestyramine (CH) or 0.75% sodium cholate (BA) for 14 d. Taurine groups were fed the diet supplemented with 3% taurine (CT, CHT and BAT). Compared to rats fed C and BA diets, serum cholesterol levels were significantly reduced in rats fed CT and BAT diets, but a significant reduction of serum cholesterol by taurine feeding was not observed in the CHT group as compared to the CH group. An increase in hepatic CYP7A1 activity due to taurine intake was observed in the CT and BAT groups. However, the simultaneous administration of cholestyramine and taurine (CHT group) did not increase hepatic CYP7A1 activity compared the intake of cholestyramine only (CH group). A significant increase in fecal bile acid excretion due to taurine intake was found only in rats fed the CT diet. In conclusion, it is suggested that taurine facilitates hepatic CYP7A1 activity regardless of the enlarged intestinal pool of bile acids due to increased intake of exogenous bile acid, and then reduces the serum cholesterol concentration.     

Effects of soybean supplementation on blood glucose, plasma lipid levels, and erythrocyte antioxidant enzyme activity in type 2 diabetes mellitus patients

The purpose of this study was to investigate the effect of soybean on blood glucose and lipid concentrations, and antioxidant enzyme activity in type 2 diabetes mellitus (DM) patients. We divided patients into two groups and fed them, respectively, a basal diet (control group) and a basal diet with 69 g/d of soybean (soybean group) for 4 weeks. Pills with roasted soybean powder were provided to the soybean supplementation group three times a day. Macronutrients intake except dietary fiber was similar between the two groups. No significant differences were observed in dietary intakes or body weight before and after the supplementation. Energy composition ratio of C:F:P was 65:19:16 in the control group, 64:20:16 in the soybean group. The blood parameters of subjects before supplementation, such as fasting blood glucose, postprandial glucose level, total cholesterol, triglyceride, LDL-cholesterol and HbA₁C were not different between the two groups. After supplementation, fasting blood glucose (p<0.001), postprandial glucose level (p<0.001) and serum triglyceride level (p<0.05) were significantly reduced in the soybean group in comparison with the control group. The total cholesterol level was not significantly different between the control and the supplemented group after 4 weeks of treatment. TBARS levels of the soybean group were not significantly different from those of the control group. The activities of catalase (p<0.01) and glutathione peroxidase (p<0.05) were significantly higher in the soybean group compared to the control group. The results of this study suggest that soybean supplementation would be helpful to control blood glucose and serum lipid in diabetic patients. Also, soybean showed an antioxidant activity that may contribute to enhance the effect of antioxidant defense. This activity contributes to protection against oxidative damage in type 2 DM patients. Soybean may have potential use in the disease management of patients with DM.     

Effects of dietary fish oil or pectin on blood pressure and lipid metabolism in the DOCA-salt hypertensive rat

This study investigated the effects of diets containing fish oil or pectin on blood pressure and lipid metabolism in the deoxycorticosterone acetate (DOCA)-salt hypertensive rat. Three groups (8 rats/group) of unilaterally nephrectomized rats were fed for 21 d one of three purified diets: a) 8% fish oil + 2% safflower oil + 5% alpha cellulose (fish oil diet), b) 10% safflower oil + 5% pectin (pectin diet), or c) 10% safflower oil + 5% alpha cellulose (control diet). Each of the diets contained 6% NaCl and all rats received DOCA (30 mg/kg body wt, subcutaneously) twice weekly. Systolic blood pressure of rats fed fish oil was significantly lower (P less than 0.05) than that of rats fed the control diet; there was no significant difference between the pectin and control groups. Plasma renin activity and net sodium and potassium balances were similar among the three groups. Plasma total cholesterol, LDL cholesterol and HDL cholesterol were significantly lower (P less than 0.05) in the group fed the fish oil diet than in the group fed the control diet. Total, LDL and HDL cholesterol did not differ between rats fed the pectin and rats fed the control diet. Plasma triglyceride concentration did not differ among the three groups. Thus, dietary fish oil attenuated the development of DOCA-salt hypertension, unrelated to alterations of net sodium balance. Fish oil feeding also lowered total, LDL and HDL cholesterol, but did not alter the HDL/LDL ratio. In contrast, dietary pectin exerted no effect on blood pressure or lipid metabolism.     

Dietary taurine enhances cholesterol degradation and reduces serum and liver cholesterol concentrations in rats fed a high-cholesterol diet.

The effect of taurine on hypercholesterolemia induced by feeding a high-cholesterol (HC) diet (10g/kg) to rats was examined. When various amounts of taurine (0.25, 0.5, 1, 2.5, 5, 10, 20, 30, 40 or 50 g/kg diet) were supplemented to HC for 2 wk, serum total cholesterol gradually and significantly decreased in a dose-dependent manner and normalized at the dose of 10 g taurine/kg, compared with the control (cholesterol free) diet group. By contrast, serum HDL-cholesterol was elevated by taurine supplementation. The HC diet caused a significant decrease in the concentration of taurine in serum, liver and heart compared to that in the control group, and the effective dose of supplemental taurine to improve its reduction was 2.5 g/kg diet. In the hypercholesterolemic rats fed the HC diet, the excretion of fecal bile acids and hepatic cholesterol 7 alpha-hydroxylase (CYP7A1) activity and its mRNA level increased significantly, and the supplementation of taurine further enhanced these indexes, indicating an increase in cholesterol degradation. The abundance of mRNA for Apo A-I, one of the main components of HDL, was reduced by HC and recovered by taurine supplementation. Agarose gel electrophoresis revealed that, in hypercholesterolemic rats fed the HC diet, the serum level of the heavier VLDL increased significantly, but taurine repressed this increase and normalized this pattern. Significant correlations were observed between the time- and dose-dependent increases of CYP7A1 gene expression and the decrease of blood cholesterol concentration in rats fed the HC diet supplemented with taurine (time, r = -0.538, P < 0.01, n = 32; dose, r = -0.738, P < 0.001, n = 20). These results suggest that the hypocholesterolemic effects of taurine observed in the hypocholesterolemic rats fed the HC diet were mainly due to the enhancement of cholesterol degradation and the excretion of bile acid.