膳食脂肪、肠道微生物与宿主健康的研究进展

作为三大主要营养物质之一,膳食脂肪为人体提供能量和营养。膳食脂肪摄入不当会破坏肠道微生物的稳态,影响宿主的代谢状况,增加慢性疾病发生的风险。建立疾病动物模型是研究肠道微生物与宿主健康的重要手段。文中综述了膳食脂质的数量和种类、肠道微生物和宿主代谢之间的相互作用及其可能的作用机制,阐述了基于不同的疾病动物模型,膳食脂质影响肠道微生物的结构和功能,以及对宿主代谢的调节,为深入了解膳食脂质、肠道微生态和宿主健康三者之间的关系提供了依据。     

膳食脂肪酸调节肠道菌群促进机体健康的研究进展

阐述了不同类型的膳食脂肪酸对肠道菌群的调节作用及其在慢性疾病中的研究进展,为未来脂肪酸的个体化健康膳食管理和疾病防治提供科学依据。     

膳食纤维对肥胖相关的肠道微生态的影响

研究发现,肠道微生态的改变与肥胖等代谢性疾病相关。膳食纤维作为饮食的一部分,通过在肠道的作用改变肠道菌群比例及丰度、改善炎症反应、调节肠道激素及脂质代谢来改善肥胖,但膳食纤维在防治肥胖方面的推荐摄入量、种类及与肠道菌群的作用机制还需进一步研究。本文对膳食纤维对肥胖相关的肠道微生态的影响的研究进展进行了综述。     

褐藻膳食纤维对机体代谢及其肠道菌群调节作用的研究进展

褐藻膳食纤维（海藻酸盐,Alg）是存在于海洋食用藻类中的一种酸性多糖,具有多种生物活性作用。研究表明,褐藻膳食纤维可有效地改善肠道菌群的组成结构,通过菌群代谢膳食纤维发酵产物调节宿主机体的代谢水平,从而改善肥胖、糖尿病等代谢相关性疾病。从作为食品添加剂的角度出发,对褐藻膳食纤维作用于人和动物模型体重、血糖、脂代谢以及肠道菌群的效果加以综述,并探讨其潜在机制,为海洋功能性产品的开发和应用提供科学依据。     

多种营养素强化饮料、膳食纤维饮料对健康影响的定性循证研究

目的：检索国内外相关文献,综合分析多种营养素强化饮料、膳食纤维饮料与健康的关系。方法：在PubMed、Embase、Medline、Cochrane、中国生物医学文献服务系统、万方数据知识服务平台和中国知网等7个数据库检索自1998年1月—2019年6月国内外公开发表的相关研究文献,纳入以人为研究对象的研究,排除重复、不完整、无法获得全文的文献等,语种限定为中文和英文。结果：本次检索到文献3 913篇,共纳入9篇作为本次研究的主要证据。多种营养素（维生素、矿物质）强化的饮料对儿童和孕妇进行干预后,血红蛋白水平升高了（2.76~8.6g/L）,血清铁蛋白水平升高了（15.42pmol/L~0.25μmol/L）,贫血率下降了（42%~51%）。膳食纤维饮料与肠道健康之间的关系尚不明确,一项研究结果显示,饮用膳食纤维饮料能显著增加双歧杆菌群和乳酸菌群,但显著降低梭菌数量;另一项研究却发现,饮用膳食纤维饮料后各种菌群均无显著性差异。食用膳食纤维的食品或饮料可以使BMI降低0.84kg/m2,体重降低2.52kg,体脂降低0.41%,还可以降低食欲。膳食纤维食品/饮料的干预,可以使空腹血糖降低0.17mmol/L,空腹胰岛素降低15.88pmol/L;在早餐后、午餐后和整个测试期间,葡萄糖反应分别降低了53%、17%和34%;胰岛素应答分别降低了78%、11%和22%。结论：饮用多种营养素强化饮料可以减少儿童、孕妇的贫血率,饮用含膳食纤维的饮料可以帮助控制体重和血糖水平,但是含膳食纤维的饮料与肠道健康之间的关系尚需进一步研究。     

麦麸膳食纤维对健康受试者血糖变化的影响

研究健康中年人进食含麦麸膳食纤维的食品后2 h的血糖变化特点,为麦麸膳食纤维的开发利用提供理论依据。方法：选取健康志愿者14人,连续2天分别测定他们的空腹血糖、进食普通馒头后2 h的血糖和进食麦麸膳食纤维馒头后2 h的血糖。结果：志愿者进食含膳食纤维早餐后2 h血糖增量比进食普通早餐后2 h的血糖增量减少0.8 mmol/L,二者差异显著（P<0.001）。结论：麦麸膳食纤维能显著降低健康人的餐后血糖。     

菌物膳食纤维研究

菌物已成为膳食纤维开发和利用的新的潜在资源。为了进一步开发和利用菌物中的膳食纤维资源,作者对目前的研究成果进行了综述,包括膳食纤维的概念、生理活性和分析方法、及菌物中膳食纤维的化学组成、开发利用等方面内容。     

益生菌与肠道健康

肠道菌群与人体肠道健康密切相关.益生菌在防治感染、调节机体菌群平衡,提高机体免疫力和儿童生长发育等发挥关键作用.本文主要介绍了益生菌与肠道健康的主要作用机制及益生菌在消化道疾病的应用.     

膳食纤维及其生理保健作用的研究进展

膳食纤维被称为“第七营养素”,是过去30年来的研究热点。本文参考近5-6年来的最新研究成果,综述了膳食纤维的定义、成分及测定方法,膳食纤维的理化特性、生理保健作用、适宜推荐量及其应用现状和发展前景,对人们全面认识膳食纤维与人体健康的关系有较大的参考价值。     

Review: Dietary fiber utilization and its effects on physiological functions and gut health of swine

Although dietary fiber (DF) negatively affects energy and nutrient digestibility, there is growing interest for the inclusion of its fermentable fraction in pig diets due to their functional properties and potential health benefits beyond supplying energy to the animals. This paper reviews some of the relevant information available on the role of different types of DF on digestion of nutrients in different sections of the gut, the fermentation process and its influence on gut environment, especially production and utilization of metabolites, microbial community and gut health of swine. Focus has been given on DF from feed ingredients (grains and coproducts) commonly used in pig diets. Some information on the role DF in purified form in comparison with DF in whole matrix of feed ingredients is also presented. First, composition and fractions of DF in different feed ingredients are briefly reviewed. Then, roles of different fractions of DF on digestion characteristics and physiological functions in the gastrointestinal tract (GIT) are presented. Specific roles of different fractions of DF on fermentation characteristics and their effects on production and utilization of metabolites in the GIT have been discussed. In addition, roles of DF fermentation on metabolic activity and microbial community in the intestine and their effects on intestinal health are reviewed and discussed. Evidence presented in this review indicates that there is wide variation in the composition and content of DF among feed ingredients, thereby their physico-chemical properties in the GIT of swine. These variations, in turn, affect the digestion and fermentation characteristics in the GIT of swine. Digestibility of DF from different feed ingredients is more variable and lower than that of other nutrients like starch, sugars, fat and CP. Soluble fractions of DF are fermented faster, produce higher amounts of volatile fatty acid than insoluble fractions, and favors growth of beneficial microbiota. Thus, selective inclusion of DF in diets can be used as a nutritional strategy to optimize the intestinal health of pigs, despite its lower digestibility and consequential negative effect on digestibility of other nutrients.     

膳食纤维与慢性非传染性疾病发生风险的关系

近年来慢性非传染性疾病的患病率呈"井喷"式增长,是全球致死和致残的首位原因,它主要发生在低、中收入国家中,严重危害了公共健康并加重了卫生经济负担。大量研究表明医学营养治疗对遏制慢性非传染性疾病的发生发展具有积极作用。膳食纤维作为健康饮食的重要组成部分,是维系公共健康不可缺少的一种营养素。由于它不被胃肠道消化吸收,也不产生能量,我们过去曾错误地认为它是一种"无营养物质"。随着科学的深入发展,膳食纤维的健康获益不断地被发现和证实,现被定义为第七类营养素。如今我国居民饮食结构愈发精细化,膳食纤维更成为了研究者们关注的焦点。本文将对膳食纤维进行系统阐述,总结其与常见慢性非传染性疾病发生风险的关系及其可能的作用机制,并对我国居民及常见慢性非传染性疾病患者的膳食纤维摄入现状及趋势进行报道。     

Dietary copper and human health: Current evidence and unresolved issues

Although copper (Cu) is recognized as an essential trace element, uncertainties remain regarding Cu reference values for humans, as illustrated by discrepancies between recommendations issued by different national authorities. This review examines human studies published since 1990 on relationships between Cu intake, Cu balance, biomarkers of Cu status, and health. It points out several gaps and unresolved issues which make it difficult to assess Cu requirements. Results from balance studies suggest that daily intakes below 0.8 mg/day lead to net Cu losses, while net gains are consistently observed above 2.4 mg/day. However, because of an incomplete collection of losses in all studies, a precise estimation of Cu requirements cannot be derived from available data. Data regarding the relationship between Cu intake and potential biomarkers are either too preliminary or inconclusive because of low specificity or low sensitivity to change in dietary Cu over a wide range of intakes. Results from observation and intervention studies do not support a link between Cu and a risk of cardiovascular disease, cognitive decline, arthritis or cancer for intakes ranging from 0.6 to 3 mg/day, and limited evidence exists for impaired immune function in healthy subjects with a very low (0.38 mg/day) Cu intake. However, data from observation studies should be regarded with caution because of uncertainties regarding Cu concentration in various foods and water. Further studies that accurately evaluate Cu exposure based on reliable biomarkers of Cu status are needed.     

肠道菌群与慢性病关系的研究进展

肠道菌群是机体重要的“内分泌器官”和“代谢调节器”,它可以通过自身的成分、代谢物及衍生物等参与调控机体的代谢、免疫和内分泌等多个系统。肠道菌群与机体共存,互惠互利,共同维持机体健康。目前,慢性病已成为危害人类健康的首要问题,在我国慢性病形势也依旧严峻,防控迫在眉睫。近年研究证实肠道菌群结构或功能的改变与肥胖、2型糖尿病和脂肪肝等一系列慢性病的发生发展密切相关,并可通过改善肠道菌群紊乱延缓疾病进程。本文就肠道菌群与一些常见慢性病关系的研究进展进行简要综述,旨在为后续开展肠道菌群与相关疾病的研究提供参考。

     

Enriched arabinoxylan in corn fiber for value-added products

A two-step process is evaluated to separate the hexose component in wet milling corn fibers from the pentose component for production of value-added products. Corn fibers were first pretreated with hot water at 121°C for 1 h followed by glucoamylase hydrolysis to remove starch. The remaining solid was then treated with hot water at 140–170°C followed by an enzymatic hydrolysis to further separate the hexose and pentose components. After the second pretreatment, the enzymatic digestibility of cellulose was much better than that of arabinoxylan. As a result, up to 90% arabinoxylan in corn fibers was retained in a solid form after the enzyme hydrolysis, while most of the hexose components were removed.     

Intestinal stem cells and stem cell-based therapy for intestinal diseases

Currently, many gastrointestinal diseases are a major reason for the increased mortality rate of children and adults every year. Additionally, these patients may cope with the high cost of the parenteral nutrition (PN), which aids in the long-term survival of the patients. Other treatment options include surgical lengthening, which is not sufficient in many cases, and intestinal transplantation. However, intestinal transplantation is still accompanied by many challenges, including immune rejection and donor availability, which may limit the transplant’s success. The development of more safe and promising alternative treatments for intestinal diseases is still ongoing. Stem cell-based therapy (SCT) and tissue engineering (TE) appear to be the next promising choices for the regeneration of the damaged intestine. However, suitable stem cell source is required for the SCT and TE process. Thus, in this review we discuss how intestinal stem cells (ISCs) are a promising cell source for small intestine diseases. We will also discuss the different markers were used to identify ISCs. Moreover, we discuss the dominant Wnt signaling pathway in the ISC niche and its involvement in some intestinal diseases. Additionally, we discuss ISC culture and expansion, which are critical to providing enough cells for SCT and TE. Finally, we conclude and recommend that ISC isolation, culture and expansion should be considered when SCT is a treatment option for intestinal disorders. Therefore, we believe that ISCs should be considered a cell source for SCT for many gastrointestinal diseases and should be highlighted in future clinical applications.     

绿茶摄入量对小鼠肠道微生物及酶活性的影响

目的从肠道微生态角度研究绿茶摄入量对小鼠肠道微生物和酶活性的影响,探析饮茶(绿茶)有益健康的机制,为饮茶做出科学指导。方法将SPF级实验小鼠随机分为正常对照组、低浓度绿茶摄入组、中浓度绿茶摄入组和高浓度绿茶摄入组。低、中、高浓度绿茶摄入组分别给予10%、20%和30%(g/g)的茶水溶液,连续灌胃1个月后采集空肠至回肠段内容物进行微生物和酶活性分析,同时观察实验动物体质量变化情况。结果各实验组小鼠体质量增长与对照组相比无明显差异;与对照组相比,低浓度绿茶摄入组小鼠肠道乳酸菌数降低而细菌数升高,中浓度摄入组乳酸菌数、细菌以及双歧杆菌数显著降低,高浓度摄入组细菌数、双歧杆菌数升高而乳酸菌数显降低著,且中浓度摄入组乳酸菌数和细菌数均极显著地低于低浓度摄入组;由酶活性分析可看出,与对照组小鼠相比,各实验组小鼠肠道淀粉酶和蛋白酶活性均升高而木聚糖酶活性显著降低。结论摄入一定量的绿茶对肠道微生物有一定的调节作用,可提高淀粉酶和蛋白酶活性而益于机体健康。     

术前补充益生菌对肠道手术患者术后肠道菌群及肠黏膜屏障功能的影响

目的 探讨术前补充益生菌对肠道手术患者术后肠道菌群及肠黏膜屏障功能的影响。方法 选取肠道手术患者86例,随机分为观察组和对照组各43例。两组患者术前予以常规肠道准备,术后给予等营养支持及抗生素等治疗。观察组患者术前7 d开始加用双歧杆菌三联活菌胶囊温水口服,630 mg/次,2次/d。观察两组患者术后肠道功能恢复及感染并发症情况,并比较术前7 d及术后首次自然排便时两组患者肠道菌群数量及肠黏膜屏障指标变化。结果 观察组患者术后肠鸣音恢复时间、肛门排气时间、排便时间均短于对照组（均P0.05）。术后首次自然排便时两组患者血清D-乳酸和DAO水平高于术前7 d时（P<0.05）,且观察组患者术后D-乳酸和DAO水平低于对照组（P<0.05）。结论 肠道手术患者术前补充益生菌可调节肠道菌群,降低肠黏膜通透性,改善其肠道功能,减少术后感染并发症的发生率。     

食源性肠道疾病的微生态防治进展

肠道是一个复杂的微生态系统, 其中存在着数以万亿计的微生物以及丰富的营养物质, 微生物群依赖肠道营养物质生长并经长期的进化适应而特异性地存在于宿主肠道, 通过其代谢活动及其产物维持宿主的微生态稳态。肠道微生物可抵抗外来病原微生物的入侵和定植, 预防肠道疾病的发生, 其作用机制包括竞争营养物质和生态位、产生拮抗细菌素、干扰群体感应和免疫介导等。饮食和药物等外界因素与遗传因素均可改变宿主的肠道环境, 从而影响机体对入侵病原微生物的抵抗。本文就肠道食源性疾病的微生态防治研究进行综述, 为预防和治疗肠道感染性疾病提供参考。