全谷豆复合包经SREBP-2、LDLR和Visfatin调控胆固醇代谢机制的探讨

目的探讨全谷豆复合包改善脂代谢紊乱大鼠胆固醇代谢的可能机制。方法 44只雄性SD大鼠随机分为高脂模型组、米面组、全谷豆复合包组和阴性对照组,分别给予对应饲料连续喂养8周。实验前后测定大鼠血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)及低密度脂蛋白胆固醇(LDL-C)含量;实验结束后股动脉取血,分离脏器称重,计算脏体比和脂体比,检测血清中Visfatin浓度、肝脏组织中SREBP-2 mRNA和LDLR mRNA的表达以及脂肪组织中VisfatinmRNA的表达。结果与高脂模型组和米面组相比,全谷豆复合包组大鼠体重、血清TC、TG、LDL-C水平显著下降(P<0.05),血清HDL-C水平显著升高(P<0.05)。全谷豆复合包组大鼠血清Visfatin水平显著低于高脂模型组和米面组(P<0.05);与高脂模型组和米面组比较,全谷豆复合包组大鼠肝脏组织中SREBP-2 mRNA和LDLRmRNA的表达显著升高(P<0.05),脂肪组织中Visfatin mRNA的表达明显降低(P<0.05)。结论全谷豆复合包可以改善高脂膳食诱导的脂代谢紊乱大鼠的血脂和Visfatin水平,可能的机制是全谷豆复合包能增加SREBP-2和LDLR的mRNA表达,降低Visfatin mRNA的表达,经SREBP-2、LDLR和Visfatin途径调控胆固醇的代谢,起到维持TC和LDL-C的正常水平,改善脂代谢紊乱的作用。     

乳清酸诱导大鼠脂肪肝的机制研究

目的研究乳清酸诱发大鼠脂肪肝的机制。方法将大鼠分成两组,对照组喂食AIN93标准饲料,模型组饲料中添加1%乳清酸。饲喂10d后,分别测定大鼠血清总胆固醇(total cholesterol,TC)、甘油三酯(triglyceride,TG)、高密度脂蛋白胆固醇(high density lipoprotein-cholesterol,HDL-C)含量,以及肝脏TC、TG、磷脂含量。同时测定了肝脏中脂肪酸合成酶(FAS)、肉碱棕榈酰转移酶(CPT)、微粒体甘油三酯转运蛋白(MTP)的活性和其mRNA表达量,以及固醇调节元件结合蛋白(SREBP-1c)和过氧化物酶体增殖物激活受体(PPARα)的mRNA表达量。结果乳清酸可显著提高大鼠血清TG浓度和肝脏TC、TG含量。添加乳清酸后,大鼠肝脏中FAS活性及mRNA水平明显上调,而CPT、MPT活性及mRNA水平明显下调,同时作为转录调节因子的SREBP-1cmRNA表达量增加3.13倍,PPARα mRNA表达量无明显变化。结论1%乳清酸诱发大鼠脂肪肝与SREBP-1c的表达量升高引发的脂肪合成亢进有关,并与脂肪酸氧化分解受抑制及MTP活性和基因表达量降低有关。     

我国菰米对高脂膳食大鼠血脂及炎性因子的影响

目的探讨菰米对高脂膳食诱导脂代谢紊乱大鼠血脂及炎性因子水平的调控作用。方法44只雄性SD大鼠随机分为阴性对照组、高脂模型组、米面组和菰米组;以相应饲料连续喂养8w,测定各组大鼠体重、血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)、高敏C反应蛋白(hs-CRP)等指标。结果与阴性对照组相比,高脂模型组和米面组大鼠的血清TC、TG显著上升,HDL-C显著降低;与高脂模型组和米面组比较,菰米组的血清TC、TG显著下降,HDL-C显著升高,TNF-α、hs-CRP显著下降。结论菰米具有降低脂代谢紊乱大鼠血脂的作用,并能改善高脂血症的低度炎性状态。     

不同来源膳食蛋白质对大鼠体重及其血脂的影响

目的探讨不同膳食蛋白质摄入对大鼠体重及其血脂的长期动态影响。方法选用36只雄性成年Wistar大鼠,按体重随机分为酪蛋白组、大豆蛋白组和谷豆蛋白混合组,喂养12周,检测大鼠在体重及其血脂上的变化。结果大豆蛋白组体重、脂肪湿重、脂体比、TG和TC水平均显著低于酪蛋白组相应指标(P<0.05),HDL-C水平与酪蛋白组相比无统计学差异;谷豆蛋白混合组TC和TG水平均显著低于酪蛋白组和大豆蛋白组(P<0.05),HDL-C水平高于酪蛋白组,有统计学差异(P<0.05)。结论大豆蛋白可以降低大鼠TC和TG水平,谷豆蛋白混合后对TC和TG水平降低作用更明显,并有提高HDL-C的作用。     

谷物膳食纤维促进高脂/胆固醇喂养小鼠脂肪分解机制的研究

目的探讨不同谷物膳食纤维(dietary fiber,DF)对高脂高胆固醇膳食诱导C57BL/6J小鼠体质量控制和脂肪分解的机制研究。方法 48只雄性C57BL/6J小鼠按体质量随机分为阴性对照组、模型对照组、燕麦DF组和全小麦DF组,采用预防性干预模式,干预周期为24w。测定各组小鼠血清总胆固醇(TC)、甘油三酯(TG)、血糖、游离脂肪酸(FFAs)和瘦素水平;采用Western blot法检测各组小鼠睾周脂肪组织中脂肪甘油三酯脂肪酶(ATGL)和激素敏感性脂肪酶(HSL)、磷酸化的激素敏感性脂肪酶563和660(p-HSL563和p-HSL660)的蛋白表达。结果干预24 w后,与模型对照组相比,谷物DF组小鼠体重、血脂、血糖、游离脂肪酸及瘦素水平显著下降,脂肪细胞体积变小,脂肪蓄积量减少;燕麦DF对小鼠血清TC的作用优于全小麦DF;燕麦DF和全小麦DF显著上调了脂肪分解相关蛋白ATGL和p-HSL蛋白的表达。结论燕麦DF和全小麦DF能够降低高脂高胆固醇膳食引起的体重增加,促进脂肪分解,改善脂代谢紊乱,且全小麦DF对体重控制和脂肪分解的作用优于燕麦DF。     

膳食蛋白质对大鼠脂联素及其受体基因表达影响

目的探讨不同膳食蛋白质摄入对大鼠脂联素及其受体表达的影响。方法将36只雄性成年Wistar大鼠按体重随机分为酪蛋白组、大豆蛋白组和谷豆蛋白混合组,喂养12周,观察各组大鼠血脂水平及脂肪组织脂联素、骨骼肌组织脂联素受体1(Adipo R1)和肝脏组织脂联素受体2(Adipo R2)mRNA表达水平。结果大豆蛋白组和谷豆蛋白混合组大鼠脂联素mRNA水平分别为(1.17±0.05)和(1.46±0.02),均高于酪蛋白组(0.79±0.06),AdipoR1 mRNA水平分别为(1.14±0.02)和(1.26±0.05),均高于酪蛋白组(0.89±0.06),谷豆混合蛋白组大鼠脂联素mRNA水平高于大豆蛋白组,差异均有统计学意义(P0.05);脂联素mRNA水平与血清甘油三脂(TG)水平呈负相关(r=-0.64,P0.05)。结论膳食蛋白质可影响大鼠脂联素和脂联素受体的表达,大豆蛋白和谷豆混合蛋白相对酪蛋白可上调脂联素及其受体的表达,且谷豆混合蛋白的作用更强。     

复合膳食纤维对大鼠降脂效果观察

目的：制备复合膳食纤维（dietary fiber,DF），并探讨其与3种单一 的DF对高脂血症大鼠体内脂类含量的影响。方法：健康、雌性、断乳Wistar大鼠48只，按体重随机分为6组，用高脂饲料诱发高酯血症的同时，分别添加10％的DF：纤维素（B组）、果胶（C组）、海藻酸钠（D组）、纤维素－果胶复合物（E组）、纤维素－海藻酸钠复合物（F组），以单纯的高脂饲料组为对照组（A组），8周后观察各种DF对大鼠的生长发育及脂类代谢的影响。结果：（1）添加10％的各种DF不影响大鼠的生长发育。（2）与对照组比，各种DF中不同程度降低大鼠脂质水平，且以复合物效果为佳。（3）各种DF可不同程度地增加粪重和粪酯排出量（P＜0．05，D组除外），以复合物为明显。（4）相关分析显示，血清TC、TG、LDL－C含量与粪脂含量呈负相关（P＜0．01）。结论：各种DF皆可不同程度地降低大鼠体内脂类含量，春中可溶性DF效果优于不可溶性DF，而复合DF的效果又优于单一的DF。     

膳食纤维不同成分对大鼠脂质代谢的影响

本文观察了3种不同膳食纤维(DF)制成品(纤维素、果胶、琼脂)对高胆固醇膳大鼠脂质代谢的影响。结果发现:果胶和纤维素组自实验2周末,琼脂组于6周末与对照组相比有明显的降低血清TC作用;3种DF均有不同程度降低肝胆固醇作用;各组血清TG、HDL-C,HDL_2-C,HDL_3-C间无显著差异;纤维素组和果胶组HDL-C/TC比值明显高于对照组。3种DF均可使大鼠排粪量增加,对大鼠摄食量及生长无影响。     

燕麦膳食纤维对肠道胆固醇吸收的影响及机制研究

目的研究燕麦膳食纤维(dietary fiber,DF)对高脂高胆固醇饮食小鼠肠道胆固醇吸收的影响及其机制。方法 36只雄性C57BL/6J小鼠,按体质量随机分为:阴性对照组、模型对照组、燕麦DF组,预防性干预24 w。实验结束后测定各组小鼠血清总胆固醇(TC)、甘油三酯(TG)及高密度脂蛋白胆固醇(HDL-C),计算低密度脂蛋白(LDL-c)。western blot方法测定肠道中与胆固醇吸收相关的GTP结合蛋白Sar1B、尼曼-匹克C1型类似蛋白1(NPC1L1)、清道夫受体B1(SR-B1)蛋白的表达水平。结果实验结束时,与模型对照组相比,燕麦DF组的体重、血清TC、LDL-C水平均显著下降(P0.05),HDL-C水平显著升高(P0.05);与胆固醇吸收相关的NPC1L1水平显著降低(P0.05),SR-B1无显著变化,调控NPC1L1和SR-B1的Sar1B蛋白表达水平显著升高(P0.05)。结论燕麦DF可以通过上调Sar1B降低肠道NPC1L1表达水平,从而减少肠道胆固醇吸收,降低血脂水平,改善高脂高胆固醇饮食引起的高脂血症。     

复合膳食纤维对大鼠体内脂质过氧化作用的影响

制备复合膳食纤维 (dietaryfiber,DF) ,并分别探讨复合、混合及三种单一的DF对高脂血症大鼠体内脂质过氧化作用的影响。选健康、断乳Wistar大鼠 6 4只 ,按体重随机分为 8组 ,用高脂饲料诱发高脂血症的同时 ,分别添加 10 %的DF :纤维素 (B组 )、果胶 (C组 )、海藻酸钠 (D组 )、纤维素 -果胶复合物 (E组 )、纤维素 -海藻酸钠复合物 (F组 )、纤维素 -果胶混合物 (G组 )、纤维素 -海藻酸钠混合物 (H组 ) ,以单纯的高脂饲料组为对照组 (A组 ) ,观察各种DF对大鼠的生长发育及脂质过氧化作用的影响。结果显示 :1、添加 10 %的各种DF不影响大鼠的生长发育。 2、各种DF皆可显著升高血清超氧化物歧化酶 (SOD) (P <0 0 1)、谷胱甘肽过氧化物酶 (GSH Px)活性 (P <0 0 1) ,降低丙二醛 (MDA)水平 (P <0 0 5 ,B、D组除外 ) ,提高红细胞膜的流动性 (P <0 0 5 ) ,以复合物、混合物效果为明显。 3、各种DF可不同程度地增加粪重和粪脂排出量 (P <0 0 5 ,D组除外 ) ,以复合物、混合物为明显。提示各种DF皆可不同程度地降低大鼠体内脂质过氧化作用 ,提高红细胞膜的流动性 ,其中可溶性DF效果优于不可溶性DF ,而复合、混合DF的效果又优于单一的DF ,且以复合物效果为佳     

Beyond dietary fiber.

The complexity of plant foods high in dietary fiber poses new challenges to clinical investigators and leads to many study-design dilemmas. There are basic differences in studying purified polymers, highly concentrated but not purified fibers, and diets high in high-fiber whole foods. The fibrils of the plant cell wall are most likely altered when prepared as a pure chemical entity, and when fiber concentrates (eg, wheat bran) are used, the method of preparation may alter the composition of the final product. Whole-plant, high-fiber foods are complex storehouses of a diversity of polymers, including resistant starch, and of bioactive compounds. Furthermore, the addition of a reasonable amount of high-fiber food to the diet not only adds dietary fiber but many digestible, caloric macronutrients that alter the entire diet composition. These problems and dilemmas are reviewed.     

Health benefits of dietary fiber

Dietary fiber intake provides many health benefits. However, average fiber intakes for US children and adults are less than half of the recommended levels. Individuals with high intakes of dietary fiber appear to be at significantly lower risk for developing coronary heart disease, stroke, hypertension, diabetes, obesity, and certain gastrointestinal diseases. Increasing fiber intake lowers blood pressure and serum cholesterol levels. Increased intake of soluble fiber improves glycemia and insulin sensitivity in non-diabetic and diabetic individuals. Fiber supplementation in obese individuals significantly enhances weight loss. Increased fiber intake benefits a number of gastrointestinal disorders including the following: gastroesophageal reflux disease, duodenal ulcer, diverticulitis, constipation, and hemorrhoids. Prebiotic fibers appear to enhance immune function. Dietary fiber intake provides similar benefits for children as for adults. The recommended dietary fiber intakes for children and adults are 14 g/1000 kcal. More effective communication and consumer education is required to enhance fiber consumption from foods or supplements.     

Self-regulation training enhances dietary self-efficacy and dietary fiber consumption

OBJECTIVE: To evaluate the effectiveness of incorporating two self-regulation strategies (goal setting and self-monitoring) into a nutrition education class to enhance dietary fiber self-efficacy and foster a positive change in dietary fiber consumption. DESIGN: College students in an introductory nutrition class (n = 113) were randomly assigned to one of four treatment conditions: goal setting, self-monitoring, goal setting and self-monitoring, and no goal setting and no self-monitoring. Twenty-six college students from an introductory health class served as the control group. STATISTICAL ANALYSES: The main and interaction effects of goal setting and self-monitoring on postintervention variables were analyzed using analysis of covariance with baseline intake levels as the covariate. Analysis of variance was used to examine differences in the mean changes between the groups. Path analysis was conducted to analyze the causal linkage among the pretest and intervening variables to predict postintervention knowledge, self-efficacy, and fiber consumption. RESULTS: Goal setting had a significant main effect on dietary fiber self-efficacy and on dietary fiber consumption Subjects who set goals scored 15% higher on the dietary fiber self-efficacy scale and consumed 91% more fiber than subjects who did not set goals. Self-monitoring had no significant main effect on either dietary fiber self-efficacy or dietary fiber consumption. There was no significant interaction between goal setting and self-monitoring. Changes in dietary fiber scores differed between the groups. Increases in dietary fiber for the goal setting and self-monitoring group were significantly higher than the goal-setting, self-monitoring, no goal setting and no self-monitoring, and control groups. In addition, the goal setting only group had significantly greater increases in fiber intake than the self-monitoring, no goal setting and no self-monitoring, and control groups. Changes in self-efficacy scores were significantly different between the groups. The goal setting and goal setting and self-monitoring groups had significantly higher self-efficacy scores than the control group. Path analysis revealed that both goal setting and self-monitoring affected dietary fiber consumption through knowledge and dietary fiber self-efficacy, goal setting had a strong direct effect on fiber consumption, and postintervention knowledge affected fiber consumption only through self-efficacy. APPLICATIONS/CONCLUSIONS: Our findings suggest that dietary change requires active self-regulation of food intake. Combining goal setting and self-monitoring significantly enhances dietary behavior change. This strategy can easily be incorporated into nutrition education or counseling programs to enhance dietary behavior change.     

Saccharification of Okara fiber by plant dietary fiber hydrolases

In this paper, the saccharification process of okara fiber with pectinase, xylanase and cellulase was investigated as a preliminary attempt to effectively utilize okara fiber. The solubilization of okara fiber was raised in proportion to the number of enzymes used; that is, by a single enzyme, two enzymes and three enzymes, in that order. The saccharification of okara fiber was much more completed by a combination of pectinase, xylanase and cellulase than by using individual preparations. This multi-enzyme system liberated sugars equivalent to 80% of the original okara fiber by weight. Moreover the structure of okara fiber gradually disintegrated by hydrolytic reactions with pectinase, xylanase and cellulase in turns. These results suggest that the saccharification of okara fiber progresses by the cooperative action of pectinase, xylanase and cellulase.     

Relationships among crude fiber, neutral detergent fiber, in vitro dietary fiber, and in vivo (rats) dietary fiber in wheat foods.

The in vivo dietary fiber contents of wheat milling fractions and wheat foods, determined in rat feeding experiments, were compared with dietary fiber values determined in vitro with pronase alpha-amylase digestion. Both types of dietary fiber values were compared with crude fiber and neutral detergent fiber values in the same materials. Regression analyses indicated close correlation amongst all values determined. It appears that laboratory analysis for crude fiber, neutral detergent fiber, or in vitro dietary fiber accurately predicts in vivo dietary fiber (rats) for wheat milling fractions when the laboratory result is adjusted by means of an appropriate regression equation.