Efficacy of phytosterols and fish-oil supplemented high-oleic-sunflower oil rich diets in hypercholesterolemic growing rats

Phytosterols (P) and fish-oil (F) efficacy on high-oleic-sunflower oil (HOSO) diets were assessed in hypercholesterolemic growing rats. Controls (C) received a standard diet for 8 weeks; experimental rats were fed an atherogenic diet (AT) for 3 weeks, thereafter were divided into four groups fed for 5 weeks a monounsaturated fatty acid diet (MUFA) containing either: extra virgin olive oil (OO), HOSO or HOSO supplemented with P or F. The diets did not alter body weight or growth. HOSO-P and HOSO-F rats showed reduced total cholesterol (T-chol), non-high-density lipoprotein-cholesterol (non-HDL-chol) and triglycerides and increased HDL-chol levels, comparably to the OO rats. Total body fat (%) was similar among all rats; but HOSO-F showed the lowest intestinal, epididymal and perirenal fat. However, bone mineral content and density, and bone yield stress and modulus of elasticity were unchanged. Growing hypercholesterolemic rats fed HOSO with P or F improved serum lipids and fat distribution, but did not influence material bone quality.     

中药红曲复方制剂降脂作用的实验研究

[目的]探讨中药红曲复方制剂对降低高脂血症模型大鼠血脂水平的疗效。[方法]采用高脂饲料喂养SD大鼠建立预防性高脂血症模型,将实验大鼠分成阴性对照组、模型对照组、阳性对照组、低剂量组、中剂量组和高剂量组。连续灌胃给药30d,观察中药红曲复方制剂对高脂血症大鼠血清甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)和高密度脂蛋白胆固醇(HDL-C)的影响。[结果]与阴性对照组比较,高脂饲料连续喂养30d后,模型对照组大鼠血清TG、TC和LDL-C显著升高(P0.01);与模型对照组比较,给药30d后,阳性对照组TG、TC和LDL-C显著降低(P0.05);低剂量组大鼠血清TG显著降低(P0.05),中剂量组和高剂量组血清TG、TC和LDL-C显著地降低(P0.01);各剂量组大鼠血清HDL-C无统计学差异(P0.05)。[结论 ]中药红曲复方制剂可有效控制并降低血脂水平。     

RELATIONSHIP BETWEEN ABSORPTION OF CHOLESTEROL AND SERUM PLANT STEROLS

Serum levels of β-sitosterol and campesterol are related to the fractional absorption of cholesterol and may serve as markers for cholesterol absorption.     

Extraction and determination of phytosterols from corn oil foots

By saponification and extraction of corn oil foots abandoned as waste during oil refining, a mixture of phytosterols was obtained, and its major components were determined as β-sitosterol, campesterol and stigmasterol by gas chromatographic analysis. The mixture is very cheap and regarded as an excellent substrate for direct fermentation of C-17 keto steroid intermediate for various steroid pharmaceuticals.     

Phytosterol stearate esters elicit similar responses on plasma lipids and cholesterol absorption but different responses on fecal neutral sterol excretion and hepatic free cholesterol in male Syrian hamsters

The dietary impact of specific phytosterols incorporated into phytosterol fatty acid esters has not been elucidated. Therefore, we tested the hypothesis that phytosterol esters containing different sterol moieties (sitosterol, sitostanol, or stigmasterol) but the same fatty acid moiety (stearic acid) produce different effects on cholesterol metabolism. Male Syrian hamsters were fed sitosterol, sitostanol, and stigmasterol stearate esters (25 g/kg diet) in an atherogenic diet containing cholesterol (1.2 g/kg) and coconut oil (80 g/kg). The phytosterol stearates produced no decrease in cholesterol absorption or plasma non-high-density lipoprotein cholesterol despite a reduction in liver free cholesterol in hamsters fed both sitosterol and sitostanol stearate diets. In addition, sitosterol stearate significantly increased fecal esterified and total neutral sterol excretion. Stigmasterol stearate did not differ from control in neutral sterol excretion, plasma lipids, or hepatic lipid concentration. Sitosterol stearate demonstrated the highest level of net intestinal hydrolysis, whereas sitostanol and stigmasterol stearate equivalently demonstrated the lowest. The cholesterol-lowering effect in liver—but not plasma—and the limited presence of fecal free sterols indicate that intact (unhydrolyzed) phytosterol stearates may impact cholesterol metabolism by mechanisms unrelated to the role of free phytosterols. The consumption of phytosterol esters at 2.5% of the diet elicited only modest impacts on cholesterol metabolism, although sitosterol stearate had a slightly greater therapeutic impact by lowering liver free cholesterol and increasing esterified and total neutral sterol fecal excretion, possibly due to a greater level of intestinal hydrolysis.     

植物甾醇对大鼠脂质代谢紊乱的预防作用

目的研究植物甾醇对高脂饮食大鼠脂质代谢的影响。方法40只雄性SD大鼠随机分为基础对照组（普通饲料喂养）、高脂模型组（高脂饲料喂养）、植物甾醇低剂量组（高脂饲料喂养,每天100mg／kg植物甾醇灌胃）和植物甾醇高剂量组（高脂饲料喂养,每天200mg／kg植物甾醇灌胃）。分别于实验结束时（6周末）测定各组大鼠的体质量、血脂水平、肝脏脂肪含量及体脂含量。结果实验结束时,3组高脂饮食大鼠的体质量、肝脏脂肪含量、体脂含量以及血清TC、TG、LDL—C水平均明显高于基础对照组（P〈0．05）,血清HDL—C水平低于基础对照组（P〈0．05）。与高脂模型组比较,植物甾醇高剂量组大鼠的体质量增加量较少（P〈0．05）,体脂含量较低（P〈0．05）;植物甾醇低、高剂量组大鼠肝脏脂肪含量及血清TC、TG和LDL—C水平均显著低于高脂模型组（P〈0．05）。结论植物甾醇具有预防高脂饮食大鼠脂质代谢紊乱的作用。高剂量植物甾醇可减少高脂饮食大鼠体质量的增加和体脂含量。     

Ezetimibe

Ezetimibe is a cholesterol absorption inhibitor that significantly lowers low- density lipoprotein cholesterol (LDL-C), and favourably affects triglyceride and high-density lipoprotein cholesterol blood levels in monotherapy and in combination with statins. Hepatic and extrahepatic (peripheral) cholesterol synthesis are well-known sources of cholesterol found in LDL-C. However, the emergence of ezetimibe has highlighted intestinal cholesterol absorption as an additional, important source of cholesterol in LDL-C, and has better illuminated how genetic factors, dietary content, pharmaceutical agents, and nuclear receptor activation (such as liver X receptors) all influence the relative contribution of these important cholesterol sources to LDL-C. In fact, investigations into ezetimibe have sometimes challenged existing scientific dogma, has prompted reconsideration of older data, and has helped create ‘new’ paradigms in cholesterol metabolism. Thus, ezetimibe's efficacy, excellent tolerability, and safety has not only expanded potential treatment options for dyslipidaemic patients, but also has promoted exploration of new frontiers of lipid research towards a better understanding of cholesterol metabolism.     

Possible anti‐obesity effects of phytosterols and phytostanols supplementation in humans: A systematic review and dose–response meta‐analysis of randomized controlled trials

Present meta‐analysis investigates the effects of phytosterols and phytostanol (PS) supplementation on anthropometric indices, using data from randomized controlled trials. We performed a systematic search in the databases: PubMed, Scopus, Cochran, and Web of Science. Weighted mean difference (WMD) with 95% confidence intervals (CIs) were presented. Overall, 79 randomized controlled trials investigated the effects of PS on anthropometric indices. Meta‐analysis results did not reveal any significant effect of PS supplementation on weight (66 trials‐WMD: ?0.083 kg; CI [?0.233, 0.066]; I² = 42.5%), percentage fat mass (6 trials‐WMD: ?0.090%; CI [?0.789, 0.610]; I² = 0.0%), and waist circumference (WC; 5 trials‐WMD: ?0.039 cm; CI [?0.452, 0.374]; I² = 0.0%). However, body mass index (BMI) significantly decreased after PS supplementation (39 trials‐WMD: ?0.063 kg/m2, p = 0.024, I² = 25.1%). Subgroup analyses showed that PS supplementation in subjects with baseline BMI ≥25 and hyperlipidemic significantly decreased body weight and BMI. The overall results showed that although PS supplementation did not affect anthropometric indices (except BMI), baseline status regarding BMI and hyperlipidemia and also dose and duration could be contributing factors for favorable effects.     

Effects of soy and other natural products on LDL:HDL ratio and other lipid parameters: A literature review

Abnormal lipid levels contribute significantly to the risk of coronary heart disease, a major cardiovascular disease and a serious health problem. Various dietary and pharmacologic treatments have been devised to reduce elevated blood cholesterol levels. Soy protein, soluble fiber, and plant sterol/ester-containing margarines are promising new food-component candidates that may help to realize this goal. Of particular interest in this context is the LDL:HDL ratio, a strong predictor of cardiac events. This report is a review of more than 50 recent trials to determine how such dietary components and garlic affect the LDL:HDL ratio and other lipid parameters. Consumption of new soy products containing high, fixed levels of isoflavones, cotyledon soy fiber, and soy phospholipids (Abaco and Abalon) significantly reduced the LDL:HDL ratio by up to 27%. Soluble dietary fibers such as psyllium and beta glucan from oat bran had a variable effect on LDL-cholesterol levels in the studies analyzed. Plant sterol esters, when consumed in margarines, lowered the LDL:HDL ratio by up to 22%. On average, Abacor and Abalon reduced the LDL:HDL ratio by 20%, LDL cholesterol by 15%, total cholesterol by 10%, and triglycerides by 6%, and increased HDL cholesterol by 5%. The new soy-based supplements may therefore play a valuable role in reducing cardiovascular risk.