Insulin resistance as key factor for linking modulation of gut microbiome to health claims and dietary recommendations to tackle obesity

BackgroundCurrent dietary and public health recommendations addressing obesity do not as yet include recommendations pertaining to the gut microbiome. As a corollary, no microbiome-related health claims made on foods have as yet been proposed.ScopeThe MyNewGut project aims, amongst others, to provide guidance for the establishment of dietary and public health recommendations related to the role microbiome in the onset and development of obesity. Moreover, the project's forthcomings should allow the compilation of a guidance document for microbiome-related health claims.Key findingsOf all the physiological effects resulting from changes in the microbiome, insulin resistance is the most direct diet-modifiable parameter related to obesity. Improving insulin resistance is considered to be the key health benefit conferred by the targeted modulation of the gut microbiome, through the development and application of foods containing microbiome-targeted fibers and micro-organisms.ConclusionsIn order to facilitate guidance for the development of public health and dietary recommendations, as well as for health claim substantiation related to the gut microbiome, foods containing microbiome-targeting dietary fibers and microorganisms will be developed and studies with these foods should provide for the total body of clinical evidence specifically addressing the central theme of ‘insulin resistance’ in obesity, still leaving ample room for the inclusion of other parameters of interest. The latter is pivotal since an impact of other parameters on obesity should be addressed as well, particularly in view of the multifaceted modes of action of the microbiome.     

Understanding the gut microbiome of dairy calves: Opportunities to improve early-life gut health

Early gut microbiota plays a vital role in the long-term health of the host. However, understanding of these microbiota is very limited in livestock species, especially in dairy calves. Neonatal calves are highly susceptible to enteric infections, one of the major causes of calf death, so approaches to improving gut health and overall calf health are needed. An increasing number of studies are exploring the microbial composition of the gut, the mucosal immune system, and early dietary interventions to improve the health of dairy calves, revealing possibilities for effectively reducing the susceptibility of calves to enteric infections while promoting growth. Still, comprehensive understanding of the effect of dietary interventions on gut microbiota—one of the key aspects of gut health—is lacking. Such knowledge may provide in-depth understanding of the mechanisms behind functional changes in response to dietary interventions. Understanding of host–microbial interactions with dietary interventions and the role of the gut microbiota during pathogenesis at the site of infection in early life is vital for designing effective tools and techniques to improve calf gut health.     

Evidence for the effects of yogurt on gut health and obesity

Obesity is associated with increased risk for chronic diseases, and affects both developed and developing nations. Yogurt is a nutrient-dense food that may benefit individuals with lactose intolerance, constipation and diarrheal diseases, hypertension, cardiovascular diseases, diabetes, and certain types of cancer. Emerging evidence suggests that yogurt consumption might also improve the health of obese individuals. Obesity is often accompanied by chronic, low-grade inflammation perpetuated by adipose tissue and the gut. In the gut, obesity-associated dysregulation of microbiota and impaired gut barrier function may increase endotoxin exposure. Intestinal barrier function can be compromised by pathogens, inflammatory cytokines, endocannabinoids, diet, exercise, and gastrointestinal peptides. Yogurt consumption may improve gut health and reduce chronic inflammation by enhancing innate and adaptive immune responses, intestinal barrier function, lipid profiles, and by regulating appetite. While this evidence suggests that yogurt consumption is beneficial for obese individuals, randomized-controlled trials are needed to further support this hypothesis.     

Understanding the effects of dietary components on the gut microbiome and human health

Food Science and Biotechnology - The gut microbiome is the complex microbial ecosystem found in the gastrointestinal tract of humans and animals. It plays a vital role in host development,...     

食用菌多糖调控肠道菌群研究进展

多糖是食用菌的主要活性物质之一,具有抗氧化、抗肿瘤、抗炎、免疫调节等生物活性。文章从食用菌多糖的功效与结构、人体肠道菌群组成、分布与功能以及食用菌多糖如何调控肠道菌群影响人体健康方面进行了综述,同时对食用菌多糖的后续研究提出了建议。     

Longitudinal changes of human milk oligosaccharides,breastmilk microbiome and infant gut microbiome are associated with maternal characteristics

Human milk oligosaccharides (HMOs) play an important role in infant health. This study aimed to investigate the association of maternal characteristics with HMOs, human breastmilk (HBM) microbiome and infant gut microbiome over the first three months of lactation. Chinese mothers and infant pairs (n = 110) were included in this prospective cohort. Secretor status linked with α1,2-fucosyltransferase expression was determined by the presence of total α1,2-fucosylated HMOs in HBM for 75.8% of the mothers. The concentration of dominant HMOs significantly decreased over three months except for 3’-fucosyllactose. In addition to the elevated levels of α1,2-fucosylated HMOs, other neutral HMOs significantly reduced in secretors milk. Alpha-diversity of HBM and infant gut microbiome significantly increased over time, and an elevated abundance of Bifidobacterium and decreased levels of Streptococcus, Staphylococcus and Clostridium in the infant gut microbiota were noted. Multi-association analysis indicated maternal age and body mass index significantly correlated with specific HMOs and infant growth. Our study provides pivotal data on Chinese HMOs distribution profile, and their association with maternal characteristics and the infant gut microbiome.     

Adipokines: implications for female fertility and obesity

Obesity is associated with a diverse set of metabolic disorders, and has reproductive consequences that are complex and not well understood. The adipose tissue-produced leptin has dominated the literature with regards to female fertility complications, but it is pertinent to explore the likely role of other adipokines--adiponectin and resistin--as our understanding of their biological functions emerge. Leptin influences the developing embryo, the functioning of the ovary and the endometrium, interacts with the release and activity of gonadotrophins and the hormones that control their synthesis. In this review such biological actions and potential roles of the adipokines leptin, adiponectin and resistin are explored in relation to female fertility and the complexity of the obese metabolic state.     

肠道菌群与肥胖关系的研究进展

肥胖是威胁人类健康的重要慢性病之一,肠道菌群结构失调在其发生、发展中起着重要作用。肠道菌群可促进能量吸收、调控脂肪的合成和储存、诱导机体慢性低度炎症,最终导致肥胖及后续的代谢障碍。阐明肠道菌群与肥胖的关系及作用机制可能会为肥胖的防控与治疗提供新的靶点。     

Human health-promoting interactions between hydrocolloid-structured foods and the gut microbiome in the digestive tract: Editorial

There is a growing interest to overcome such diet-related health issues through the interactions with gut microbiome. A complex network of interactions between nutrition, gut microbiota and health has gradually emerged, which has been rarely explored in its whole. Imbalance of the normal gut microbiota has been linked with gastrointestinal conditions. This editorial highlighted the recent developments in the hydrocolloid-structured foods and the gut microbiome in the digestive tract.     

Correlations between oligosaccharides in breast milk and the composition of the gut microbiome in breastfed infants

The composition of the microbiome in the early stages of life can directly affect the health of developing infants, and prior evidence suggests that human milk oligosaccharides (HMO) are critical regulators in the maintenance of a healthy gut microbiota in infants. Herein, we conducted an analysis of the gut microbiota of 1-mo-old breastfed infants from Jining and Harbin, China, and a corresponding analysis of the HMO profiles in samples of maternal breast milk. Quantification of HMO was conducted via liquid chromatography-mass spectrometry, and bacterial DNA sequencing was employed for characterization of the fecal microbiota. The abundances of total neutral oligosaccharides, lactodifucotetraose, lacto-N-fucopentaose I, and disialyl-lacto-N-tetraose were significantly increased in samples from the Jining group relative to the Harbin group. Bifidobacterium were the predominant microbial species in infants from both Harbin and Jining, with these levels being significantly higher in the former set. Correlation analyses evaluating microbes and 19 different HMO indicated that HMO were beneficial to the development of the gut microbiota in young infants. The predominance of Bifidobacterium in these microbial communities suggests that their ability to efficiently utilize HMO can contribute to the homeostasis of the gut microflora, with breast milk-derived HMO being critical to the shaping of the gut microbiota in breastfed infants.     

蛇菰属植物化学成分和药理活性研究进展

研究日本蛇菰多糖双氧水脱色、Sevag法脱蛋白的条件并对其进行工艺优化。在单因素的基础上,以多糖脱色率为指标,采用响应面法设计三因素三水平实验对蛇菰多糖的脱色条件进行优化;以蛋白质脱除率、多糖保留率为指标,选取Sevag试剂比例（氯仿:正丁醇）、样液:Sevag试剂、振荡时间为因素水平设计响应面试验,得到最佳工艺条件。结果表明,在pH为8的条件下双氧水脱色最佳工艺为：双氧水用量为20%、脱色时间为46 min、脱色温度为60 ℃,在此条件下蛇菰多糖的脱色率为84.21%。脱蛋白最佳工艺条件为：氯仿:正丁醇5:1、样液:Sevag试剂4:1、振荡时间15 min,在此条件下,多糖保留率为81.03%,蛋白质脱除率为40.44%。双氧水和Sevag法脱色脱蛋白工艺稳定,方法可行操作简单,适用于蛇菰多糖的脱色、脱蛋白。     

Dietary fat and gut microbiota: mechanisms involved in obesity control

ABSTRACT

Obesity is a serious global health problem that is directly related to various morbidities manifestation. Intestinal dysbiosis has been implicated on obesity pathogenesis. Diet composition can alter gut microbiota, regardless of energy intake. Dietary fatty acids quality may affect gut microbiota composition, which in turn may affect host metabolic health. The mechanisms by which the different type of FFA modulate gut microbiota is yet poor elucidate and there is a lack of studies regard to this. Fatty acids may act in cell membrane, interfere with energy production, inhibit enzymatic activities, impair nutrient absorption and generate toxic compounds to cells, leading to growth inhibition or even bacterial death. The beneficial effect of the consumption of n-3 polyunsaturated fatty acids (PUFA) and conjugated linoleic acid (CLA) on microbiota, unlike n-6 PUFA and saturated fatty acids has been suggested. n-3 PUFA consumption promotes desirable changes on obese intestinal microbiota making it similar to that of normal weight individuals. More studies are needed to better understand the effect of CLA on microbiota and host health. Long term human controlled clinical trials must be conducted to allow us to understand the complex interaction between dietary fat, intestinal microbiota and obesity.     

Synergism between resveratrol and other phytochemicals: implications for obesity and osteoporosis

Resveratrol, a phytoalexin, has gained much attention recently due to its effects on sirtuins. While the anti-cancer properties of resveratrol have been extensively investigated, the anti-adipogenic and osteogenic effects of resveratrol are also gaining considerable interest. The finding that resveratrol supplementation mimics caloric restriction prompted researchers to study the effects of resveratrol on lipid metabolism. Mesenchymal stem cells are the precursors for both adipocytes and osteoblasts. In the aging population, differentiation to adipocytes dominates over the differentiation to osteoblasts in bone marrow, contributing to the increased tendency for fractures to occur in the elderly. Thus, an inverse relationship exists between adipocytes and osteoblasts in the bone marrow. Resveratrol acts on several molecular targets in adipocytes and osteoblasts leading to a decrease in adipocyte number and size and an increase in osteogenesis. Furthermore, resveratrol in combination with genistein and quercetin synergistically decreased adipogenesis in murine and human adipocytes. A recent in vivo study showed that phytochemicals including resveratrol in combination with vitamin D prevented weight gain and bone loss in a postmenopausal rat model. Therefore, combinations of resveratrol with other phytochemicals may lead to potential novel potent therapies for both obesity and osteoporosis.     

Importance of the fat content within the cheese-matrix for blood lipid profile,faecal fat excretion,and gut microbiome in growing pigs

Cheese and butter have been shown to affect blood lipids differently. This parallel-arm, randomised, controlled study in 36 crossbred growing sows compared the effect of diets with either regular-fat cheese (REG), reduced-fat cheese + butter (RED) or butter (BUT) on blood lipids, faecal fat and energy excretion and gut microbiome in pigs. A 14-d run-in period was followed by 14-d interventions with macronutrient-matched diets. Fasting total cholesterol and HDL-cholesterol after 14 days were higher in REG compared with BUT, but only tended to be higher in RED. Compared with BUT, REG and RED had higher faecal fat excretion. Faecal energy excretion was only higher in REG, and this correlated with a lower microbiome Firmicutes-to-Bacteroidetes ratio. In conclusion, dairy fat consumed as cheese or butter caused different metabolic effects. Differences between reduced-fat cheese+butter and butter were less pronounced than differences between regular-fat cheese and butter, suggesting an impact of the dairy-matrix.     

Impact of polyphenols from black tea and red wine/grape juice on a gut model microbiome

Food and beverage products derived from fruit and vegetables contain polyphenols, which have been associated with various health benefits. Polyphenols may influence health through direct uptake in the intestine but also upon interaction with the gut microbiota for example by modification of the microbial composition or by conversion of the polyphenols to further bioactive compounds. So far, there are limited studies of complex polyphenols on the human gut microbiota especially using modern molecular technologies. Most studies investigating effects of dietary polyphenols have focused on single molecules or bacterial strains. In the current study, an in vitro gut microbial ecosystem, namely simulator of the intestinal microbial ecosystem (SHIME), was challenged with either a black tea or a red wine grape extract (RWGE), both containing complex dietary polyphenol mixtures. Within the context of the model system, the effects of these interventions on both microbial numbers and composition as well as metabolite levels were assessed. Antimicrobial effects, largely confined to unculturable members of the ecosystem, were revealed by complementary microbiological techniques. Pyrosequencing analysis showed a shift in the Firmicutes:Bacteroidetes ratio for both interventions. Black tea stimulated Klebsiella, enterococci and Akkermansia and reduced bifidobacteria, B. coccoides, Anaeroglobus and Victivallis. RWGE promoted growth of Klebsiella, Alistipes, Cloacibacillus, Victivallis and Akkermansia while bifidobacteria, B. coccoides, Anaeroglobus, Subdoligranulum and Bacteroides were decreased.The study shows that these complex polyphenols in the context of a model system can modulate select members of the human gut microbiota. These members represent novel targets of polyphenol degrading or resistant microbes to be validated under physiological conditions in vivo and further investigated for polyphenol metabolism or resistance mechanisms.     

Health benefits of whole grain: effects on dietary carbohydrate quality,the gut microbiome,and consequences of processing

Grains are important sources of carbohydrates in global dietary patterns. The majority of these carbohydrates, especially in refined-grain products, are digestible. Most carbohydrate digestion takes place in the small intestine where monosaccharides (predominantly glucose) are absorbed, delivering energy to the body. However, a considerable part of the carbohydrates, especially in whole grains, is indigestible dietary fibers. These impact gut motility and transit and are useful substrates for the gut microbiota affecting its composition and quality. For the most part, the profile of digestible and indigestible carbohydrates and their complexity determine the nutritional quality of carbohydrates. Whole grains are more complex than refined grains and are promoted as part of a healthy and sustainable diet mainly because the contribution of indigestible carbohydrates, and their co-passenger nutrients, is significantly higher. Higher consumption of whole grain is recommended because it is associated with lower incidence of, and mortality from, CVD, type 2 diabetes, and some cancers. This may be due in part to effects on the gut microbiota. Although processing of cereals during milling and food manufacturing is necessary to make them edible, it also offers the opportunity to still further improve the nutritional quality of whole-grain flours and foods made from them. Changing the composition and availability of grain carbohydrates and phytochemicals during processing may positively affect the gut microbiota and improve health.     

Regulation of leptin synthesis and secretion before birth: implications for the early programming of adult obesity

A series of epidemiological, clinical and experimental studies have shown that there are associations between the fetal and neonatal nutritional environment and the amount and distribution of adipose tissue in adult life. This review considers the evidence for these relationships and discusses the potential impact of the prenatal nutritional experience on the development of the endocrine and neuroendocrine systems that regulate energy balance, with a particular emphasis on the role of the adipocyte-derived hormone, leptin. In the rodent, leptin derived from the mother may exert an important influence on the development of the appetite regulatory neural network and on the subsequent regulation of leptin synthesis and the risk for obesity in the offspring. In species such as the human and sheep, there is also recent evidence that the synthesis and secretion of adipocyte-derived hormones, such as leptin, are regulated in fetal life. Furthermore, the hypothalamic neuropeptides that regulate energy intake and expenditure in adult life are also present within the fetal brain and may be regulated by the prevailing level of maternal and hence fetal nutrient and hormonal signals, including leptin. This work is important in determining those initiating mechanisms within the 'fat-brain' axis in early life that precede the development of adult obesity.     

Nutritional modulation of gut microbiota in the context of obesity and insulin resistance: Potential interest of prebiotics

Obesity in humans leads to changes in the composition of gut microbiota, some of those changes being reversed upon dieting and changes in dietary habits. The studies devoted to understand how gut microbes control host energy homeostasis are of interest, in order to estimate how specific nutrients that induce changes in gut microbiota composition and/or activity – such as prebiotics – could be relevant in the management of obesity and related disorders. This review presents the potential molecular mechanisms allowing the gut microbiota to control host energy homeostasis, and presents the potential mechanisms evoked in the improvement of obesity by colonic nutrients that target the gut microbiota. It also discusses the relevance of this new area of research in human nutrition and health.