膳食成分与肠道菌群相互作用

肠道菌群是机体的组成部分,维持肠道菌群的平衡对促进健康有重要意义。影响肠道菌群稳态的因素除了宿主遗传、健康状态、生活习惯、分娩方式等外,膳食是肠道菌群结构和功能的主要因素之一。通过膳食摄入的营养素和非营养性生物活性成分的类型、数量及食物搭配会影响肠道菌群构成和代谢。本文综述了膳食成分对肠道菌群结构的影响、肠道菌群对食物消化吸收过程中的作用以及对宿主健康的影响,可为膳食干预来调节肠道菌群、预防疾病过程中提供参考和新的思路。     

膳食因素对肠道菌群的影响

肠道菌群与人类宿主间的相互关系受到膳食因素的影响,膳食是维持肠道菌群和宿主之间共生关系的重要组成部分,膳食成分中含有肠道菌群代谢所需的底物,并通过多种方式影响人类肠道菌群的结构和功能.现就膳食对肠道菌群结构和代谢功能的影响,以及膳食干预在消化系疾病中的作用等研究进展进行简要阐述.     

饮食对肠道菌群的影响

消化道中有复杂的微生物群,包括大约30个属,400～500多种微生物.影响肠道菌群的因素有宿主因素和环境因素,而环境因素中最重要的就是饮食因素.膳食纤维、脂类、蛋白质等饮食成分对肠道菌群有不同的影响.肠道菌群对人体健康有重要作用,肠道菌群的变化可以引起很多疾病,因此理解饮食因素与肠道菌群之间的关系,可以对疾病有更深层次的理解,有利于找到预防及治疗某些疾病的方法.     

肠道菌群与子宫内膜癌

肠道菌群可完成宿主生理所需的多种功能，如保护宿主免受病原体入侵，调节代谢、发育，维持免疫和神经系统的稳态。尽管肠道菌群受年龄、生活习惯、生理活动、激素水平、抗生素及放射治疗等因素的影响，但其在健康成人体内仍保持稳态。近年来，许多研究报道肠道菌群组成改变与恶性肿瘤和其他疾病的发生发展有关，如炎性肠病、高血压、多囊卵巢综合征（PCOS）、肥胖、糖尿病、结直肠癌、乳腺癌等。有文献报道子宫内膜癌发生与PCOS、肥胖、胰岛素抵抗、高血压、高雌激素水平和年龄等因素有关；肠道菌群稳态的破坏会促进肥胖、高血压、PCOS及高雌激素水平的发生，提示肠道菌群与子宫内膜癌之间可能存在某种关联。本文总结近年来关于肠道菌群与子宫内膜癌风险因素的关联以及可能的肿瘤发生机制的研究进展，为日后继续研究子宫内膜癌的新型诊断、预后和治疗策略提供参考。     

肠道菌群与肥胖及胰岛素抵抗的关系

肠道菌群是一个复杂的生态系统,与宿主相互作用,影响宿主代谢及多种生理功能。研究发现,肠道菌群的改变可引发慢性炎症反应,进而导致肥胖、胰岛素抵抗等代谢失调。本文就肠道菌群与肥胖、胰岛素抵抗发生、发展的关系及部分机制进行综述。     

肠道菌群与子宫内膜癌

肠道菌群可完成宿主生理所需的多种功能,如保护宿主免受病原体入侵,调节代谢、发育,维持免疫和神经系统的稳态。尽管肠道菌群受年龄、生活习惯、生理活动、激素水平、抗生素及放射治疗等因素的影响,但其在健康成人体内仍保持稳态。近年来,许多研究报道肠道菌群组成改变与恶性肿瘤和其他疾病的发生发展有关,如炎性肠病、高血压、多囊卵巢综合征(PCOS)、肥胖、糖尿病、结直肠癌、乳腺癌等。有文献报道子宫内膜癌发生与PCOS、肥胖、胰岛素抵抗、高血压、高雌激素水平和年龄等因素有关;肠道菌群稳态的破坏会促进肥胖、高血压、PCOS及高雌激素水平的发生,提示肠道菌群与子宫内膜癌之间可能存在某种关联。本文总结近年来关于肠道菌群与子宫内膜癌风险因素的关联以及可能的肿瘤发生机制的研究进展,为日后继续研究子宫内膜癌的新型诊断、预后和治疗策略提供参考。     

高脂饮食诱导肠道菌群紊乱在结直肠癌发生发展中的作用

目的 近年来,全球范围内结直肠癌(colorectal cancer, CRC)发病率和死亡率持续上升。许多研究表明,高脂饮食是结直肠癌的危险因素;肠道菌群与结直肠癌的发生发展密切相关,高脂饮食可显著改变肠道菌群的组成。紊乱的肠道菌群分泌细菌毒素,破坏肠道屏障和肠上皮细胞基因组,促进炎症反应,影响免疫系统、宿主代谢平衡,最终促进结直肠癌的发生发展。肠道菌群的变化也能影响化疗和免疫治疗的效果。本文对高脂饮食诱导的肠道菌群紊乱影响结直肠癌的发生发展相关研究进行综述。     

肠道菌群与喂养的关系及其同大脑交流的研究进展

近年来,国内外对婴儿肠道菌群定植状况及其相关影响因素进行了深入的研究。肠道菌群对机体消化、代谢、免疫调节和抵抗疾病等功能发育和完善有着不可替代的作用。婴儿时期是肠道菌群建立的关键时期,分娩方式、抗生素的应用、生活习惯、外界环境、喂养方式等均对肠道菌群的建立产生影响,其中喂养方式是影响肠道菌群建立的关键因素之一。近期研究表明,肠道菌群还同大脑存在广泛的交流,包括免疫调节途径、神经内分泌途径、代谢产物途径及迷走神经途径,为进一步阐明神经精神疾病的发病机制提供思路。     

肠道菌群与喂养的关系及其同大脑交流的研究进展

近年来,国内外对婴儿肠道菌群定植状况及其相关影响因素进行了深入的研究。肠道菌群对机体消化、代谢、免疫调节和抵抗疾病等功能发育和完善有着不可替代的作用。婴儿时期是肠道菌群建立的关键时期,分娩方式、抗生素的应用、生活习惯、外界环境、喂养方式等均对肠道菌群的建立产生影响,其中喂养方式是影响肠道菌群建立的关键因素之一。近期研究表明,肠道菌群还同大脑存在广泛的交流,包括免疫调节途径、神经内分泌途径、代谢产物途径及迷走神经途径,为进一步阐明神经精神疾病的发病机制提供思路。     

肠道菌群紊乱与女性生殖内分泌疾病相关性研究现状

肠道菌群、宿主和环境3者密切关联,构成机体平衡的肠道微生态系统,肠道菌群参与宿主多项生理功能。肠道菌群结构平衡在宿主神经系统、内分泌系统及全身性疾病中扮演着重要角色。在生殖内分泌疾病中,与肠道菌群紊乱的相关性研究尚处于起步阶段。既往研究结果显示,肠道菌群紊乱与阴道内环境变化相关,亦参与多种生殖内分泌疾病,如多囊卵巢综合征(PCOS),子宫内膜异位症等的发生、发展及转归。因此,调节肠道菌群对女性生殖内分泌疾病的治疗有积极意义。笔者拟就肠道菌群紊乱参与生殖内分泌疾病的作用机制的最新研究进展进行阐述。     

肠道菌群功能研究进展

人体中寄居着大量的微生物,即共生菌群,这些菌群的基因总和称为微生物组。存在于人体中的各种菌群和微生物组对人体的健康和疾病发挥着重要作用。正常情况下肠道菌群与人体处于共生关系,具有防御外源性感染、促进免疫系统的成熟与平衡、营养与代谢等生理功能。肠道共生菌群的紊乱则与许多疾病有关,包括过敏性疾病、自身免疫性疾病、代谢性疾病、细菌感染和结肠癌等。     

Human Milk Microbiota and Oligosaccharides: A Glimpse into Benefits,Diversity, and Correlations

Human milk represents a cornerstone for growth and development of infants, with extensive array of benefits. In addition to exceptionally nutritive and bioactive components, human milk encompasses a complex community of signature bacteria that helps establish infant gut microbiota, contributes to maturation of infant immune system, and competitively interferes with pathogens. Among bioactive constituents of milk, human milk oligosaccharides (HMOs) are particularly significant. These are non-digestible carbohydrates forming the third largest solid component in human milk. Valuable effects of HMOs include shaping intestinal microbiota, imparting antimicrobial effects, developing intestinal barrier, and modulating immune response. Moreover, recent investigations suggest correlations between HMOs and milk microbiota, with complex links possibly existing with environmental factors, genetics, geographical location, and other factors. In this review, and from a physiological and health implications perspective, milk benefits for newborns and mothers are highlighted. From a microbiological perspective, a focused insight into milk microbiota, including origins, diversity, benefits, and effect of maternal diet is presented. From a metabolic perspective, biochemical, physiological, and genetic significance of HMOs, and their probable relations to milk microbiota, are addressed. Ongoing research into mechanistic processes through which the rich biological assets of milk promote development, shaping of microbiota, and immunity is tackled.     

肠道菌群与儿童神经系统疾病的研究进展

近年来,随着基因测序技术的发展,肠道菌群的研究越来越多。类似于人自身的基因,每个人的肠道菌群都是独一无二的,可比作“人类的第二指纹”。肠道菌群在人出生后3年内进展最快,而这也正好是婴幼儿大脑发育最关键的时期。随着年龄的增长,其肠道菌群或微生物组成也会发生变化。脑肠轴在大脑与肠道之间的联系有着重要的作用,而肠道菌群可通过多种途径直接或间接地影响脑肠轴进而对大脑功能产生影响。目前肠道菌群在成人的神经系统疾病研究较多,而肠道菌群与儿童神经系统疾病的研究尚较少,主要疾病包括孤独症谱系障碍、癫痫、注意力缺陷多动障碍以及青春期抑郁症等。因此,本文主要对肠道菌群与儿童神经系统疾病近年来的研究进展进行综述。     

Probiotics that modify disease risk

Probiotics are defined as live bacterial preparations with clinically documented health effects in humans. Probiotics have specific properties and targets in the human intestinal tract and intestinal microbiota. Each probiotic strain, independent of its genus and species is unique and, thus, the properties and the human health effects of each strain have to be assessed in a case-by-case manner. Understanding the mechanisms by which probiotics influence the normal intestinal microbiota and counteract aberrancies in microbiota would facilitate the use of probiotics for both dietary management and reduction in risk of specific diseases. Development of intestinal microbiota is an important factor affecting the health of the newborn. Recent studies suggest that specific bacterial components, especially the bifidobacteria, have a key impact on development of a healthy balanced infant microbiota. The composition of infant and child intestinal microbiota may become aberrant and thus influence the development of diarrheal, inflammatory, and allergic diseases. Based on this understanding, positive health effects of probiotics have been reported in the management of diarrheal, inflammatory, and allergic diseases in infants. Most recently, a reduction in risk of atopic diseases followed early administration of specific probiotics.     

婴幼儿肠道菌群的影响因素及其在肠道免疫中的作用

婴幼儿肠道菌群自定植起,随着年龄增长,需历经多次改变才能最终形成微生物稳态。本文主要介绍婴幼儿肠道菌群受分娩阶段、喂养方法、饮食结构、生活环境、疾病因素、药物使用后发生的改变,及其在肠道免疫功能形成中发挥的重要作用。     

婴幼儿肠道菌群的影响因素及其在肠道免疫中的作用

婴幼儿肠道菌群自定植起,随着年龄增长,需历经多次改变才能最终形成微生物稳态。本文主要介绍婴幼儿肠道菌群受分娩阶段、喂养方法、饮食结构、生活环境、疾病因素、药物使用后发生的改变,及其在肠道免疫功能形成中发挥的重要作用。     

Dietary Curdlan Enhances Bifidobacteria and Reduces Intestinal Inflammation in Mice

β-glucan consumption is known for its beneficial health effects, but the mode of action is unclear. While humans and mice lack the required enzymes to digest β-glucans, certain intestinal microbes can digest β-glucans, triggering gut microbial changes. Curdlan, a particulate β-glucan isolated from Alcaligenes faecalis, is used as a food additive. In this study we determined the effect of curdlan intake in mice on the intestinal microbiota and dextran sodium sulfate (DSS)-induced intestinal inflammation. The effect of curdlan on the human intestinal microbiota was assessed using i-screen, an assay for studying anaerobic microbial interactions. Mice received oral gavage with vehicle or curdlan for 14 days followed by DSS for 7 days. The curdlan-fed group showed reduced weight loss and colonic inflammation compared to the vehicle-fed group. Curdlan intake did not induce general microbiota community changes, although a specific Bifidobacterium, closely related to Bifidobacterium choerinum, was observed to be 10- to 100-fold more prevalent in the curdlan-fed group under control and colitis conditions, respectively. When tested in i-screen, curdlan induced a global change in the microbial composition of the healthy intestinal microbiota from a human. Overall, these results suggest that dietary curdlan induces microbiota changes that could reduce intestinal inflammation.     

Microbiote intestinal et stéatopathie métabolique

Non alcoholic fatty liver disease or NAFLD is a disease with a large spectrum of liver injury that could appear in overweight or obese individuals with a metabolic syndrome. However, among overweight or obese, only a subset of individuals develops severe forms of NAFLD. Thus, the susceptibility of NAFLD is related to cofactors that could be protective or conversely noxious. Studies carried out in rodent models have demonstrated that the intestinal microbiota is a cofactor with a causal role in NAFLD. The bacterial patterns as well as the metabolites produced by intestinal bacteria are directly involved in the mediation of their effects, although the mechanisms are far from being fully identified. Changing intestinal microbiota by using fibers, prebiotics or probiotics can prevent or improve NAFLD in murine models. The translation of these data to human therapeutics is encouraging but remains limited. Indeed, there is clearly a dysbiosis associated with the different stages of NAFLD. The first clinical trials performed in patients to improve NAFLD showed beneficial effects although their analysis remains complicated given the many confounding factors, such as the use of metformin or proton inhibitors. A first clinical trial using a metabolite from Akkermansia muciniphila, suggests that new therapeutic approaches will emerge in the coming years based either on the modulation of the intestinal microbiota directly or on the modulation of intestinal microbiota targets.     

Developmental microbial ecology of the neonatal gastrointestinal tract

The gastrointestinal tract of a normal fetus is sterile. During the birth process and rapidly thereafter, microbes from the mother and surrounding environment colonize the gastrointestinal tract of the infant until a dense, complex microbiota develops. The succession of microbes colonizing the intestinal tract is most marked in early development, during which the feeding mode shifts from breast-feeding to formula feeding to weaning to the introduction of solid food. Dynamic balances exist between the gastrointestinal microbiota, host physiology, and diet that directly influence the initial acquisition, developmental succession, and eventual stability of the gut ecosystem. In this review, the development of the intestinal microbiota is discussed in terms of initial acquisition and subsequent succession of bacteria in human infants. Intrinsic and extrinsic factors influencing succession and their health significance are discussed. The advantages of modern molecular ecology techniques that provide sensitive and specific, culture-independent evaluation of the gastrointestinal ecosystem are introduced and discussed briefly. Further advances in our understanding of developmental microbial ecology in the neonatal gastrointestinal tract are dependent on the application of these modern molecular techniques.