食物营养与辅食对肠道菌群的影响

食物是人体和肠道菌群共同的营养物质。不同食物提供的各种营养素不但是身体的需要也会影响肠道微生物的组成和丰度,辅食添加使肠道菌群发生重要的转变,引入新食物并向家庭食物过渡,会增加婴儿肠道菌群的多样性,多种食物的摄入,保持重要的食物结构,对维持肠道有益的微生物种类和数量,对人体近期和远期的健康均有重要影响。     

肠道菌群及微生态调节剂在儿科临床中的作用

人类的微生物系统由寄生的微生物群以及人体构成,微生物在人体成长与发展的过程中发挥着不可替代的生理作用,如果人体与微生物之间出现失衡的情况,那么人体就会受到疾病的侵袭。肠道菌群对人体有着极为重要的影响,其在人体微生物中可以占到78%以上的比重,因此加强对肠道菌群的关注是十分重要且必要的。儿童年龄小,身体机能较差,因此很容易出现肠道菌群紊乱等问题,如果不对患儿予以有效的治疗,患儿的生命健康将受到严重的威胁。文中将对肠道菌群进行必要的分析,并提出利用微生态调节剂治疗儿科相关疾病的作用。     

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。     

谈谈肥胖与消化道疾病的关系

肠道菌群紊乱 人的消化道黏膜表面生存着数量惊人的微生物群,细菌的细胞数量高达100万亿,是人体细胞数量的10倍。这些细菌帮助人体分解和消化食物,长期进食高脂食物可引起肠道细菌菌群紊乱,使双歧杆菌等对身体有益的细菌数量减少,对身体有害的细菌数量增加,使肠道黏膜产生慢性炎症,导致肠黏膜的通透性增加、营养物质吸收增加,     

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。     

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.     

肠道菌群与妊娠期糖代谢相关性及益生菌应用相关研究进展

肠道菌群是居住在人体肠道黏膜表面的微生物群, 在正常妊娠期间随妊娠进展肠道菌群构成可发生动态改变;妊娠糖尿病是一种常见妊娠并发症, 可影响母婴肠道菌群, 通过增加胰岛素抵抗、引发炎症反应等机制影响母婴远期糖代谢。通过饮食结构调整及益生菌应用可能调节肠道微生物群, 改善妊娠糖尿病母婴糖代谢状况。文章综述了肠道菌群与妊娠期糖代谢的相关性, 并讨论了饮食及益生菌对肠道菌群的影响。     

膳食对肠道菌群的影响与糖尿病的关联研究现状

近年来,研究发现肠道生态环境与人体健康密切相关,日益引起国内外学者的重视.肠道菌群与肠道中食物分解、营养物质的吸收和代谢、内分泌功能和促炎性反应等有关,肠道菌群的失调可影响宿主的能量代谢平衡,从而导致多种慢性代谢性疾病,如肥胖和糖尿病等.因为饮食习惯不同造成肠道菌群组成及其新陈代谢有所差异,可见膳食对肠道菌群有重要的影响.目前,关于膳食对肠道菌群的影响与糖尿病的研究尚少,本文就相关研究进行综述.     

肠道生态与环境化学物质之间的相互作用是否促发肥胖和糖尿病?

[背景]肠道菌群是肥胖和糖尿病发病的重要因素,但对于肠道菌群在环境化学物质的毒理动力学中所起的作用却知之甚少,包括那些最近发现具有致肥作用和致糖尿病作用的物质. [目的]我们把肠道生态和环境化学物质与肥胖及糖尿病之间具有独立关联的证据整合起来,为对这些环境因子如何与这些疾病相互作用提供一个框架,并确定未来的研究需求. [方法]通过调查在无菌或抗生素处理过的实验动物和人类中评估饮食改变和微生物变化如何影响肥胖和糖尿病的研究,对那些评估环境化学物质暴露会如何影响肥胖和糖尿病研究的优缺点进行总结,并辨认出肠道生态会如何影响环境化学物质处置的研究空白. [结果]越来越多的证据表明,肠道菌群的组成成分与环境化学物质暴露一样均可影响肥胖和糖尿病.毒理学和药理学文献也表明,肠道菌群的个体差异可能会通过如下途径来影响化学物质代谢:直接激活化学物质、生物转化所需代谢产物的耗竭、宿主生物转化酶的活性变化、改变肝肠循环、改变环境化学物质和/或食物中抗氧化剂的生物利用度、肠道蠕动和屏障功能的改变. [结论]肠道菌群的变化可能会影响人体毒理动力学,并增加个体对致肥物质和致糖尿病物质的暴露.与肥胖和糖尿病的全球流行作斗争需要多管齐下,其中应该包括:更加重视理解和控制肠道微生物个体差异对人体内环境化学物质处置的影响.     

健康新知

正常饮食可维持菌群平衡人们已知体内微生物的平衡对全身健康非常重要。最近,日本研究人员证明,正常饮食可以在人的口腔和肠道中建立和维持菌群平衡。人体是人类细胞与微生物的共生体,这些微生物对人体的众多生理功能都有调节作用。     

Dysbiotic Events in Gut Microbiota: Impact on Human Health

The human body is colonized by a large number of microbes coexisting peacefully with their host. The most colonized site is the gastrointestinal tract (GIT). More than 70% of all the microbes in the human body are in the colon. The microorganism population is 10 times larger of the total number of our somatic and germ cells. Two bacterial phyla, accounting for more than 90% of the bacterial cells, dominate the healthy adult intestine: Firmicutes and Bacteroidetes. Considerable variability in the microbiota compositions between people is found when we look at the taxonomic level of species, and strains within species. It is possible to assert that the human microbiota could be compared to a fingerprint. The microbiota acts as a barrier from pathogens, exerts important metabolic functions, and regulates inflammatory response by stimulating the immune system. Gut microbial imbalance (dysbiosis), has been linked to important human diseases such as inflammation related disorders. The present review summarizes our knowledge on the gut microbiota in a healthy context, and examines intestinal dysbiosis in inflammatory bowel disease (IBD) patients; the most frequently reported disease proven to be associated with changes in the gut microbiota.     

Impact of dietary fat on gut microbiota and low-grade systemic inflammation: mechanisms and clinical implications on obesity

Dietary fat strongly affects human health by modulating gut microbiota composition and low-grade systemic inflammation. High-fat diets have been implicated in reduced gut microbiota richness, increased Firmicutes to Bacteroidetes ratio, and several changes at family, genus and species levels. Saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) and conjugated linolenic fatty acids share important pathways of immune system activation/inhibition with gut microbes, modulating obesogenic and proinflammatory profiles. Mechanisms that link dietary fat, gut microbiota and obesity are mediated by increased intestinal permeability, systemic endotoxemia, and the activity of the endocannabinoid system. Although the probiotic therapy could be a complementary strategy to improve gut microbiota composition, it did not show permanent effects to treat fat-induced dysbiosis. Based upon evidence to date, we believe that high-fat diets and SFA consumption should be avoided, and MUFA and omega-3 PUFA intake should be encouraged in order to regulate gut microbiota and inflammation, promoting body weight/fat control.     

Gut microbiota functions: metabolism of nutrients and other food components

The diverse microbial community that inhabits the human gut has an extensive metabolic repertoire that is distinct from, but complements the activity of mammalian enzymes in the liver and gut mucosa and includes functions essential for host digestion. As such, the gut microbiota is a key factor in shaping the biochemical profile of the diet and, therefore, its impact on host health and disease. The important role that the gut microbiota appears to play in human metabolism and health has stimulated research into the identification of specific microorganisms involved in different processes, and the elucidation of metabolic pathways, particularly those associated with metabolism of dietary components and some host-generated substances. In the first part of the review, we discuss the main gut microorganisms, particularly bacteria, and microbial pathways associated with the metabolism of dietary carbohydrates (to short chain fatty acids and gases), proteins, plant polyphenols, bile acids, and vitamins. The second part of the review focuses on the methodologies, existing and novel, that can be employed to explore gut microbial pathways of metabolism. These include mathematical models, omics techniques, isolated microbes, and enzyme assays.     

Prebiotics and the Human Gut Microbiota: From Breakdown Mechanisms to the Impact on Metabolic Health

The colon harbours a dynamic and complex community of microorganisms, collectively known as the gut microbiota, which constitutes the densest microbial ecosystem in the human body. These commensal gut microbes play a key role in human health and diseases, revealing the strong potential of fine-tuning the gut microbiota to confer health benefits. In this context, dietary strategies targeting gut microbes to modulate the composition and metabolic function of microbial communities are of increasing interest. One such dietary strategy is the use of prebiotics, which are defined as substrates that are selectively utilised by host microorganisms to confer a health benefit. A better understanding of the metabolic pathways involved in the breakdown of prebiotics is essential to improve these nutritional strategies. In this review, we will present the concept of prebiotics, and focus on the main sources and nature of these components, which are mainly non-digestible polysaccharides. We will review the breakdown mechanisms of complex carbohydrates by the intestinal microbiota and present short-chain fatty acids (SCFAs) as key molecules mediating the dialogue between the intestinal microbiota and the host. Finally, we will review human studies exploring the potential of prebiotics in metabolic diseases, revealing the personalised responses to prebiotic ingestion. In conclusion, we hope that this review will be of interest to identify mechanistic factors for the optimization of prebiotic-based strategies.     

Evolution of the Human Diet and Its Impact on Gut Microbiota,Immune Responses,and Brain Health

The relatively rapid shift from consuming preagricultural wild foods for thousands of years, to consuming postindustrial semi-processed and ultra-processed foods endemic of the Western world less than 200 years ago did not allow for evolutionary adaptation of the commensal microbial species that inhabit the human gastrointestinal (GI) tract, and this has significantly impacted gut health. The human gut microbiota, the diverse and dynamic population of microbes, has been demonstrated to have extensive and important interactions with the digestive, immune, and nervous systems. Western diet-induced dysbiosis of the gut microbiota has been shown to negatively impact human digestive physiology, to have pathogenic effects on the immune system, and, in turn, cause exaggerated neuroinflammation. Given the tremendous amount of evidence linking neuroinflammation with neural dysfunction, it is no surprise that the Western diet has been implicated in the development of many diseases and disorders of the brain, including memory impairments, neurodegenerative disorders, and depression. In this review, we discuss each of these concepts to understand how what we eat can lead to cognitive and psychiatric diseases.     

The Effects of High Fiber Rye,Compared to Refined Wheat,on Gut Microbiota Composition,Plasma Short Chain Fatty Acids,and Implications for Weight Loss and Metabolic Risk Factors (the RyeWeight Study)

Consumption of whole grain and cereal fiber have been inversely associated with body weight and obesity measures in observational studies but data from large, long-term randomized interventions are scarce. Among the cereals, rye has the highest fiber content and high rye consumption has been linked to increased production of gut fermentation products, as well as reduced risks of obesity and metabolic disease. The effects on body weight and metabolic risk factors may partly be mediated through gut microbiota and/or their fermentation products. We used data from a randomized controlled weight loss trial where participants were randomized to a hypocaloric diet rich in either high fiber rye foods or refined wheat foods for 12 weeks to investigate the effects of the intervention on gut microbiota composition and plasma short chain fatty acids, as well as the potential association with weight loss and metabolic risk markers. Rye, compared to wheat, induced some changes in gut microbiota composition, including increased abundance of the butyrate producing Agathobacter and reduced abundance of [Ruminococcus] torques group, which may be related to reductions in low grade inflammation caused by the intervention. Plasma butyrate increased in the rye group. In conclusion, intervention with high fiber rye foods induced some changes in gut microbiota composition and plasma short chain fatty acid concentration, which were associated with improvements in metabolic risk markers as a result of the intervention.     

Probiotics: Interaction with gut microbiome and antiobesity potential

Obesity is a metabolic disorder afflicting people globally. There has been a pivotal advancement in the understanding of the intestinal microbiota composition and its implication in extraintestinal (metabolic) diseases. Therefore, any agent modulating gut microbiota may produce an influential effect in preventing the pathogenesis of disease. Probiotics are live microbes that, when administered in adequate amounts, have been shown to confer health benefits to the host. Over the years, probiotics have been a part of the human diet in the form of different fermented foods consumed around the world. Their influence on different physiologic functions in the host is increasingly being documented. The antiobesity potential of probiotics is also gaining wide attention because of increasing evidence of the role of gut microbiota in energy homeostasis and fat accumulation. Probiotics have also been shown to interact with the resident bacterial members already present in the gut by altering their properties, which may also affect the metabolic pathways involved in the regulation of fat metabolism. The underlying pathways governing the antiobesity effects of probiotics remain unclear. However, it is hoped that the evidence presented and discussed in this review will encourage and thus drive more extensive research in this field.     

Comparative Analysis of the Impact of Urolithins on the Composition of the Gut Microbiota in Normal-Diet Fed Rats

The gut microbiota consists of a community of microorganisms that inhabit the large intestine. These microbes play important roles in maintaining gut barrier integrity, inflammation, lipid and carbohydrate metabolism, immunity, and protection against pathogens. However, recent studies have shown that dysfunction in the gut microbiota composition can lead to the development of several diseases. Urolithin A has recently been approved as a functional food ingredient. In this study, we examined the potentials of urolithin A (Uro-A) and B (Uro-B) in improving metabolic functions and their impact on gut microbiota composition under a metabolically unchallenged state in normal rats. Male Wistar rats (n = 18) were randomly segregated into three groups, with Group 1 serving as the control group. Groups 2 and 3 were administered with 2.5 mg/kg Uro-A and Uro-B, respectively, for four weeks. Our results showed that both Uro-A and B improved liver and kidney functions without affecting body weight. Metagenomic analysis revealed that both Uro-A and B induced the growth of Akkermansia. However, Uro-A decreased species diversity and microbial richness and negatively impacted the composition of pathogenic microbes in normal rats. Taken together, this study showed the differential impacts of Uro-A and B on the gut microbiota composition in normal rats and would thus serve as a guide in the choice of these metabolites as a functional food ingredient or prebiotic.     

Excess Vitamins or Imbalance of Folic Acid and Choline in the Gestational Diet Alter the Gut Microbiota and Obesogenic Effects in Wistar Rat Offspring

Excess vitamin intake during pregnancy leads to obesogenic phenotypes, and folic acid accounts for many of these effects in male, but not in female, offspring. These outcomes may be modulated by another methyl nutrient choline and attributed to the gut microbiota. Pregnant Wistar rats were fed an AIN-93G diet with recommended vitamin (RV), high 10-fold multivitamin (HV), high 10-fold folic acid with recommended choline (HFol) or high 10-fold folic acid without choline (HFol-C) content. Male and female offspring were weaned to a high-fat RV diet for 12 weeks post-weaning. Removing choline from the HFol gestational diet resulted in obesogenic phenotypes that resembled more closely to HV in male and female offspring with higher body weight, food intake, glucose response to a glucose load and body fat percentage with altered activity, concentrations of short-chain fatty acids and gut microbiota composition. Gestational diet and sex of the offspring predicted the gut microbiota differences. Differentially abundant microbes may be important contributors to obesogenic outcomes across diet and sex. In conclusion, a gestational diet high in vitamins or imbalanced folic acid and choline content contributes to the gut microbiota alterations consistent with the obesogenic phenotypes of in male and female offspring.