复合纤维素降脂效果观察及机理探讨

以燕麦麸、消棘皮等为主要原料，研究含不同比例可溶性膳食纤维的３种复合纤维素对大鼠脂质代谢和机体过氧化反应的影响。将ＳＤ雌性大鼠制成高脂模型分为４组，以高脂饲料作为对照组（Ａ）。喂养４周后测定其血液及肝中脂质水平及ＡＰＯ－Ａｌ、ＡＰＯ－Ｂ、粪胆汁酸盐及ＬＰＯ含量：结果表明：３种复合纤维素均能有效地降低高脂大鼠血ＴＣ、ＴＧ、ＬＤＬ－ｃ及ＡＰＯＢ、ＬＰＯ水平，并提高ＨＤＬ－ｃ含量。提示利用不同膳食纤维特点组成的复合纤维素能用于降低人群的血脂水平和ＬＰＯ水平，对于动脉粥样硬化和心血管疾病的防治具有重要意义。     

食物中可溶性纤维对大鼠脂质水平的影响

用５种不伺膳食纤维喂饲高胆固醇膳ＳＤ大鼠４周，观察对大鼠血、肝胆固醇、甘油三酯水平和肝组织学的影响。结果显示，瓜儿豆胶组至实验２周末，燕麦和沙棘皮组实验期末血清ＴＣ、ＬＤＬ－Ｃ及肝ＴＣ水平显著低于其它各组（Ｐ＜０．０５）；燕麦组血清ＨＤＬ－Ｃ显著高于高脂无纤维素对照组（Ｐ＜０．０５）；ＨＤＬ－Ｃ／ＬＤＬ－Ｃ比值燕麦和豆胶组显著高于其它各组（Ｐ＜０．０５），ＨＤＬ－Ｃ／ＴＣ值除琼脂组外，各组均明显高于对照组（Ｐ＜０．０５）；豆胶组大鼠摄食量及体重增长显著低于其它各组（Ｐ＜０．０５）。镜检发现豆胶、燕麦和沙棘皮有良好抗肝脂肪变的作用。提示：可溶性纤维能有效地降低血和肝胆固醇水平，因其成分不同降脂作用有异，其中瓜儿豆胶、燕麦食物作用明显且迅速。     

月见草油对实验性高脂血症脂质过氧化、血浆TXA2、PGI2及ET水平的影响

用含２％月见草油的高脂饲料喂饲实验性高脂血症大鼠４周，分别对血脂、血清脂质过氧化物（ＬＰＯ）、血浆超氧化物歧化酶（ＳＯＤ）、血栓素（ＴＸＡ２）、前列腺素（ＰＧＩ２）及内皮素（ＥＴ）进行了检测，并用扫描电镜对动脉内皮进行了观察。结果发现：月见草油能降低血清总胆固醇（ＴＣ）及甘油三酯（ＴＧ）含量，提高高密度脂蛋白胆固醇（ＨＤＬ－Ｃ）含量；月见草油能显著降低血清ＬＰＯ水平，提高血浆ＳＯＤ活力；月见草油组大鼠血浆ＰＧＩ２水平明显增高，而ＴＸＡ２／ＰＧＩ２比值及血浆ＥＴ水平明显下降；月见草油组大鼠肝脏脂肪蓄积稍轻于高脂对照组；扫描电镜观察亦发现月见草油组大鼠动脉内皮损伤明显轻于高脂对照组。结果提示月见草油具有良好的降脂、保护内皮细胞及预防动脉粥样硬化形成的作用     

膨化燕麦麸对大鼠血脂水平的影响及营养品质研究

方法：以天然燕麦麸为原料经挤压膨化处理后饲喂高脂血症模型大鼠４周。结果：大鼠血脂ＴＣ、ＴＧ及ＬＤＬ－Ｃ值显著低于对照组，ＨＤＬ－Ｃ值略有提高。经营养成分分析，膨化处理对燕麦麸的表观结构及营养品质也可产生良好作用。结论：挤压膨化技术是提高燕麦麸膳食纤维生理活性，改善燕麦麸口感的有效手段。     

沙棘果汁及硒强化沙棘果汁对高脂血症大鼠脂质及脂质过氧化作用的影响

给实验性高脂血症大鼠喂饲沙棘果汁及硒强化沙棘果汁，观察其对大鼠机体脂质代谢及脂质过氧化作用的影响．结果表明：沙棘果汁及硒强化沙棘果汁可显著降低大鼠血中ＴＣ、ＬＤＬ－Ｃ含量，提高ＨＤＬ－Ｃ水平，各实验组大鼠血清及肝脏脂质过氧化物（ＬＰＯ）水平显著低于高脂组，谷胱甘肽过氧化物酶（ＧＳＨ－ＰＸ）活性以硒强化沙棘果汁组增高更为显著（Ｐ＜０．０５）．提示：沙棘果汁及硒强化沙棘果汁能有效地降低高脂大鼠血ＴＣ水平，提高ＨＤＬ－Ｃ水平，并能抑制其体内脂质过氧化作用．     

膨化燕麦麸对大鼠血脂水平的影响及营养品研究

方法：以天然燕麦麸为原料经挤压膨化处理后饲喂高脂血症模型大鼠４周。结果：大鼠血脂ＴＣ、ＴＧ及ＬＤＬ－Ｃ值显著低于对照组,ＨＤＬ－Ｃ值略有提高。经营养成分分析,膨化处理对燕麦麸的表观结构及营养品质也可产生良好作用。结论：挤压膨化技术是提高燕麦麸膳食纤维生理活性,改善燕麦麸口感的有效手段。     

大豆纤维对实验性高脂大鼠动脉粥样硬化的预防作用和抗氧化效果

研究大豆纤维（ＳＦ）对实验性高脂大鼠的血液和肝组织脂质过氧化物（ＬＰＯ）水平、谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活性和血脂指标的影响。结果表明，大豆纤维膳能明显降低血清总胆固醇（ＴＣ）、低密度脂蛋白胆固醇（ＬＤＬ－Ｃ）和致动脉粥样硬化指数（ＡＩ）（Ｐ＜０．０５）。血清和肝组织ＬＰＯ水平明显下降，ＧＳＨ－Ｐｘ活力显著提高（Ｐ＜０．０５）．ＳＦ对血脂降低和对氧化低密度脂蛋白（Ｏｘ－ＬＤＬ）的阻断作用可能对防止动脉粥样硬化（ＡＳ）的形成起主要作用。     

棕榈油对中国健康青年男子血脂及脂质过氧化物水平的影响

为了研究棕榈油（ＰＡ）、豆油（ＳＯ）、猪油（ＬＡ）对正常人血脂及脂质过氧化物水平的影响，将４５名１８～２５岁健康男子分为３组，分别食用上述３种油烹调的实验膳。实验膳中脂肪占热能的３０％，其中７５％～８０％来自实验用油。预备期３周，实验期６周。结果显示：ＬＡ使受试者的低密度脂蛋白胆固醇（ＬＤＬ－Ｃ）浓度及总胆固醇与高密度脂蛋白胆固醇比值（ＴＣ／ＨＤＬ－Ｃ）水平显著升高，而ＰＡ、ＳＯ则无此影响；实验结束时，ＰＡ组ＴＣ、ＬＤＬ－Ｃ、ＴＣ／ＨＤＬ－Ｃ以及ＳＯ组的ＴＣ／ＨＤＬ－Ｃ均显著低于ＬＡ组。ＴＧ、ＨＤＬ－Ｃ和ＬＰＯ水平３组间未见显著性差异。以上实验结果表明，在食品工业及家庭烹饪中使用棕榈油可维持健康成人正常的血胆固醇水平     

紫苏油和松籽油对大鼠机体脂类和脂质过氧化的影响

在高脂饲料中分别加入６％的紫苏油和松籽油，在实验动物总能量与主要营养素摄入基本相同、脂肪占总能量３２．６％的条件下饲喂Ｗｉｓｔａｒ雄性成年大鼠３周。结果表明，紫苏油和松籽油对高脂血症大鼠均有一定的调整血脂作用。紫苏油和松籽油组大鼠血清甘油三酯（ＴＧ）、总胆固醇（ＴＣ）、低密度脂蛋白胆固醇（ＬＤＬ－Ｃ）、ＬＤＬ－Ｃ与高密度脂蛋白胆固醇（ＨＤＬ－Ｃ）的比值（ＬＤＬ－Ｃ／ＨＤ－Ｌ－Ｃ）、致动脉粥样硬化指数（ＡＩ）的增加值和ＨＤＬ－Ｃ／ＴＣ、卵磷脂胆固醇酰基转移酶（ＬＣＡＴ）活性的下降均不同程度地低于单纯食猪油的高脂对照组。紫苏油尚可提高高脂血症大鼠血清ＨＤＬ－Ｃ、高密度脂蛋白亚组分Ⅱ胆固醇（ＨＤＬ２Ｃ）水平及ＨＤＬ２－Ｃ与高密度脂蛋白亚组分Ⅲ胆固醇（ＨＤＬ３－Ｃ）比值（ＨＤＬ２－Ｃ／ＨＤＬ３－Ｃ）；松籽油未见显著升高ＨＤＬ－Ｃ作用。各组动物血清ＨＤＬ３－Ｃ水平无显著差异。紫苏油和松籽油组大鼠肝体比值低于高脂对照组。紫苏油组大鼠肝脏过氧化脂质（ＬＰＯ）含量高于松籽油和高脂对照组。但与正常组比较，紫苏油、松籽油和高脂对照组大鼠肝体比值、肝脂质含量、肝组织病理学检查显示的肝脂变程度和肝脏ＬＰＯ含量均增高，而肝组织中谷胱?     

冠心病患者体内脂质过氧化损伤的临床研究

本文测定了３０例ＣＨＤ患者及２０例健康者血脂、ＬＰＯ、ＯＸ－ＬＤＬ、ＳＯＤ、ＧＳＨ—ＰＸ水平，发现ＣＨＤ患者血浆ＨＤＬ－Ｃ、ＬＤＬ－Ｃ／ＨＤＬ－Ｃ、ＡｐｏＢ、ＬＰＯ、ＯＸ－ＬＤＬ水平明显超过健康对照者，而其血浆ＬＤＬ－Ｃ、ＡｐｏＡ１、ＡｐｏＡ１／ＡｐｏＢ、ＳＯＤ、ＧＳＨ－ＰＸ水平均明显低于健康对照者，并发现ＣＨＤ患者血浆ＬＰＯ水平与ＴＣ、ＴＧ、ＬＤＬ－Ｃ、ＬＤＬ－Ｃ／ＨＤＬ－Ｃ、ＯＸ－ＬＤＬ、ＡｐｏＢ水平呈明显正相关，与ＳＯＤ、ＧＳＨ－ＰＸ、ＡｐｏＡ１／ＡｐｏＢ水平呈明显负相关。提示ＣＨＤ患者体内存在明显的脂质过氧化损伤，其损伤的严重程度与体内脂质代谢以及抗氧化酶活性水平有关     

Soluble oat fiber tends to normalize lipoprotein composition in cholesterol-fed rats

The effect of oat fiber on VLDL, LDL and HDL composition was investigated by feeding male Sprague-Dawley rats diets containing 1.0% cholesterol and 0.2% cholic acid, and 6% dietary fiber from oat bran, high-fiber oat flour or a processed oat product for 20 d. Compared to cholesterol-fed cellulose controls, all oat fibers altered the response to cholesterol feeding as indicated by 25-45% lower total lipoprotein cholesterol, 40-60% lower VLDL + LDL cholesterol, and 25-40% higher HDL cholesterol contents, P less than 0.01. The effect of the oat fibers on VLDL composition was especially pronounced as demonstrated by 30-65% lower VLDL protein, VLDL apo E and plasma apo B concentrations. The processed oat product which contained 40% more soluble fiber than oat bran or oat flour normalized the lipoprotein profile associated with ingestion of the atherogenic diet significantly more than oat bran or oat flour. Concentration of total lipoprotein cholesterol and distribution of apo E among the VLDL and LDL fractions in the processed oat product group were similar to controls not fed cholesterol. These data indicate that ingestion of oat fiber tends to normalize the lipoprotein profile induced by feeding an atherogenic diet in the rat, and that the hypocholesterolemic effect of oat fiber is associated with its soluble fiber content.     

Oat fiber: composition versus physiological function in rats

The effect of processing on the ability of oat fiber to lower plasma and liver cholesterol concentrations in rats was studied. Male Sprague-Dawley rats were fed diets containing 6% dietary fiber as cellulose, oat bran, high fiber oat flour or one of four processed high fiber oat flours for 3 wk. All diets also contained 1.0% cholesterol and 0.2% cholic acid. At the conclusion plasma and liver concentrations of cholesterol and triglycerides were measured. All of the oat products significantly lowered plasma and liver cholesterol without depressing food intake or weight gain. As little as 4% dietary fiber in a processed oat flour significantly lowered cholesterol concentrations. Detailed fiber analysis of all of the oat fiber products revealed that processing increased the proportion of the total fiber that was soluble. The proportions recovered as total beta-glucans and total neutral sugars also increased, in part because the proportion recovered as Klason lignin decreased in all of the processed oat flours except the one prepared by a high pressure extrusion process.     

Oat bran lowers plasma cholesterol levels in mildly hypercholesterolemic men.

The effects of oat bran and wheat bran on plasma lipid concentrations were compared in a crossover study. Each bran (123 g oat bran or 54 g wheat bran) added nearly 18 g of nonstarch polysaccharide to a background diet containing about 10 g nonstarch polysaccharide. Twenty-three men (average plasma cholesterol level = 5.84 mmol/L, and low-density-lipoprotein (LDL) cholesterol level = 4.11 mmol/L) were randomly assigned to either the oat or wheat bran diet for 4 weeks and then changed to the alternate bran diet for a similar period. The oat bran diet produced significantly lower levels of plasma total cholesterol and LDL cholesterol: 5.65 +/- 0.16 and 3.88 +/- 0.15 mmol/L (mean +/- standard error) for oat bran vs 5.89 +/- 0.16 and 4.11 +/- 0.16 mmol/L for wheat bran. Food intake diaries showed that average consumption of total fat and saturated fat was identical during the two test periods, which excluded displacement of fat as an explanation for lowering of plasma cholesterol by oat bran. Our results indicate that in mildly hypercholesterolemic men, a diet high in soluble oat fiber can significantly lower plasma total cholesterol and LDL cholesterol and thus potentially lower the risk of coronary heart disease.     

Effects of oat bran, rice bran, wheat fiber, and wheat germ on postprandial lipemia in healthy adults.

Six normolipidemic males ingested on separate days a low-fiber test meal [2.8 g dietary fiber (TDF)] containing 70 g fat and 756 mg cholesterol, enriched or not with 10 g TDF as oat bran, rice bran, or wheat fiber or 4.2 g TDF as wheat germ. Fasting and postmeal blood samples were obtained for 7 h and chylomicrons were isolated. Adding fibers to the test meal induced no change in serum glucose or insulin responses. The serum triglyceride response was lower (P less than or equal to 0.05) in the presence of oat bran, wheat fiber, or wheat germ and chylomicron triglycerides were reduced with wheat fiber. All fiber sources reduced chylomicron cholesterol. Cholesterolemia decreased postprandially for 6 h and was further lowered in the presence of oat bran. Serum apolipoprotein (apo) A-1 and apo B concentrations were not affected. Thus, dietary fibers from cereals may reduce postprandial lipemia in humans to a variable extent.     

Oat bran increases serum acetate of hypercholesterolemic men.

Mechanisms for the hypocholesterolemic effects of oat bran remain unclear. Soluble fibers such as oat bran are fermented in the colon to short-chain fatty acids (SCFAs), which may enter the portal vein and attenuate hepatic cholesterol synthesis. To compare effects of oat bran and wheat bran on serum SCFA concentrations, 20 hypercholesterolemic men entered a metabolic ward and received control diets for 1 wk followed by oat-bran or wheat-bran diets for 3 wk. Oat bran decreased serum cholesterol 12.8% (P less than 0.001) whereas wheat bran had no effect. Peripheral serum SCFA concentrations were measured seven times over 14 h at the end of each diet. Serum acetate values from 1200 to 2200 were significantly higher in subjects fed oat-bran vs wheat-bran diets. Peak and incremental peak acetate values were also significantly higher than control values in subjects fed oat bran but not in subjects fed wheat bran. SCFA responses may contribute to the hypocholesterolemic effects of oat bran.     

Effects of dietary fibers on nonfasting plasma lipoprotein and apolipoprotein levels in rats.

This study was undertaken to determine whether selected dietary fibers had an effect on plasma lipoproteins, apolipoproteins and enzymes involved in cholesterol metabolism in rats. Each experimental diet contained 8% dietary fiber by weight; all animals were killed in a nonfasted state. After 4 wk, final body weight and liver cholesterol were similar in fiber-free controls and in rats fed diets containing cellulose, pectin, oat bran or wheat bran. Pectin-fed animals has significantly lower plasma cholesterol, HDL-cholesterol and apolipoprotein A-I levels, and exhibited significantly higher hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase activity than did the fiber-free control group. In addition, plasma triglyceride concentrations were lowest in pectin-fed animals. These multiple effects on lipid metabolism were not observed when oat bran, containing one-third soluble fiber, was used. Although total plasma cholesterol levels in wheat bran-fed animals were not different from those in the fiber-free controls or the cellulose-oat bran-fed animals, the LDL cholesterol level was significantly higher than in fiber-free controls or pectin-fed animals. This study demonstrate that dietary fibers included in the diet of rats are able to alter nonfasting lipoprotein cholesterol and apolipoproteins and that pectin, a soluble fiber, was most effective in lowering plasma cholesterol levels.     

Composition of high density lipoproteins in rats fed various dietary fibers

Several studies have suggested that dietary fibers, especially water-soluble sources, are effective agents for lowering plasma cholesterol. This study was undertaken to determine the effect of various fibers on the composition of apoproteins in high density lipoproteins. Rats were fed experimental diets that contained either 20% wheat bran, oat bran or cellulose or 5% pectin or guar gum for 4 weeks. Final body weight was similar among groups. HDL cholesterol and total apoprotein concentrations were not significantly altered by diet. The percentage of apo A-I was significantly elevated and apo E and the apo C's were significantly lower in the guar gum group relative to the wheat bran group. Lecithin cholesterol acyl transferase activity and the C-II-to-C-III ratio were highest in the guar gum group. Differences in the absorption and subsequent metabolism of lipid could account for differences in HDL composition.     

Effects of solvent extraction on the hypocholesterolaemic action of oat bran in the rat.

In adult male rats fed on a cholesterol-free synthetic diet, plasma cholesterol concentrations were lowest with oat bran, intermediate with cellulose and highest with wheat bran. Plasma triacylglycerols (TAG) were similar with wheat bran and cellulose but higher with oat bran. The concentrations and pools of caecal volatile fatty acids (VFA) were lowest with cellulose and equally higher with oat bran and wheat bran. Plasma VFA concentrations in the hepatic portal vein reflected those in caecal digesta and were unrelated to plasma cholesterol. Feeding oat bran after extraction with n-pentane gave plasma cholesterol concentrations similar to that found with wheat bran. Reconstitution of oat bran with extracted lipids did not restore the cholesterol-lowering effect. Addition of the extracted material to a wheat-bran diet had no effect on plasma cholesterol. Plasma TAG were higher with the oat bran and reconstituted-oat-bran diets than with wheat-bran or cellulose diets. However, extracted oat bran + safflower oil gave similar TAG concentrations to that with wheat bran. These extractions and additions did not change caecal bile acid or neutral sterol concentrations. Effects of these diets on plasma cholesterol were unrelated to their tocotrienol or tocopherol content. Addition of n-pentane to oat bran followed by evaporation of solvent gave plasma cholesterol concentrations that were significantly higher than untreated oat bran but lower than similarly treated wheat bran. It is concluded that oat bran affects cholesterol metabolism through a pentane-soluble component as well as non-starch polysaccharides. It appears that the activity of this lipid is not transferable by simple addition of the solvent extract to the whole diet.     

复合膳食纤维对大鼠脂代谢的短期作用

目的：　通过研究复合膳食纤维（ Ｄ Ｆ Ｃ） 对大鼠脂代谢的影响,以寻求降脂效果良好的最佳 Ｄ Ｆ Ｃ 比例配方,为进一步研究 Ｄ Ｆ Ｃ 可能的作用和机理提供依据。方法：　雌性、断乳 Ｓ Ｄ 大鼠４２ 只,经高脂饲料诱导成高脂血症模型后,按体重和血清总胆固醇水平均衡的原则分为６ 组,分别给予总膳食纤维水平一致但比例构成不同的四种复合膳食纤维,以高脂饲料作为对照组,观察其对大鼠血浆和肝脏脂质、粪中胆汁酸含量的影响。结果：　１ ．四种复合膳食纤维对大鼠摄食及生长发育均无不良影响。２ ．可溶性纤维（ Ｓ Ｄ Ｆ） 与不可溶性纤维（ Ｉ Ｓ Ｄ Ｆ） 比例为４ ．４ ,２ ．０ 及１ ．０ 的三种 Ｄ Ｆ Ｃ 均能显著降低高脂血症大鼠的血胆固醇（ Ｔ Ｃ） 、低密度脂蛋白胆固醇（ Ｌ Ｄ Ｌ Ｃ） 及肝胆固醇（ Ｌ Ｃ Ｈ） 水平,且这种作用与 Ｓ Ｄ Ｆ／ Ｉ Ｓ Ｄ Ｆ 比值之间密切相关;以 Ｓ Ｄ Ｆ／ Ｉ Ｓ Ｄ Ｆ＝２ ．０ 的 Ｄ Ｆ Ｃ Ｂ 作用最佳。３ ．各 Ｄ Ｆ Ｃ 均能增高大鼠血浆高密度脂蛋白胆固醇（ Ｈ Ｄ Ｌ Ｃ） 及 Ｈ Ｄ Ｌ Ｃ 与 Ｌ Ｄ Ｌ Ｃ 的比值,仍以 Ｓ Ｄ Ｆ Ｆ／ Ｉ Ｓ Ｄ Ｆ＝ ２ ．０ 的 Ｄ Ｆ Ｃ Ｂ 作用最为显著。４ ．各组动物的粪胆汁酸排泄量高     

Do beans and oat bran add to the effectiveness of a low-fat diet?

The effects of consuming an increased amount of soluble fibre as oat bran or beans were examined in 40 free-living hypercholesterolaemic men and women. The subjects were initially established on a low-fat background diet (29% of energy from fat) and then 55 g low-fibre oat bran, 55 g high-fibre oat bran or 80 g mixed cooked beans were added to their diet in random order for 6 week periods. Body weight and overall composition of the diet did not change. Plasma cholesterol and low-density lipoprotein cholesterol (LDL-C) were unchanged. High-density lipoprotein cholesterol (HDL-C) was significantly higher on all three intervention diets than on the lower fibre run-in diet. Supplementation of a moderately low-fat diet with palatable quantities of oat bran or beans without changing the overall fat intake does not appear to significantly lower cholesterol but may have a benefit by increasing HDL-C and reducing the ratio of LDL-C to HDL-C.