Decaffeinated green and black tea polyphenols decrease weight gain and alter microbiome populations and function in diet-induced obese mice

Marine red yeast supplementation improves laying performance by regulating small intestinal homeostasis in aging chickens

Recent studies have shown that age-related aging evolution is accompanied by imbalances in intestinal homeostasis. Marine red yeast (MRY) is a functional probiotic that has been shown to have antioxidant, immune and other properties. Therefore, we chose 900 healthy Hy-Line Brown hens at 433 d old as the research subjects and evaluated the correlation between intestinal health, laying performance, and egg quality in aged hens through the supplementation of MRY. These laying hens were assigned into 5 groups and received diet supplementation with 0%, 0.5%, 1.0%, 1.5%, and 2% MRY for 12 weeks. The results showed that MRY supplementation increased egg production rate, average egg weight, and egg quality, and decreased feed conversion ratio and daily feed intake (P < 0.05). The MRY supplement improved antioxidant indicators such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), stimulated villus height, and increased the villus height to crypt depth ratio (V/C ratio) in the intestine (P < 0.05). It also regulated the expression of intestinal inflammatory factors (transforming growth factor-β [TGF-β], interleukin [IL]-1β, IL-8, tumor necrosis factor-α [TNF-α]) while increasing serum immunoglobulin G (IgG) levels (P < 0.05). Furthermore, MRY supplementation upregulated the mRNA expression of tight junction proteins (occludin and zonula occludens-1 [ZO-1]), anti-apoptotic gene (Bcl-2), and autophagy-related proteins (beclin-1 and light chain 3I [LC3I]) in the intestine (P < 0.05). The MRY supplement also led to an increase in the concentration of short-chain fatty acids in the cecum, and the relative abundance of the phylum Bacteroidetes, and genera Bacteroides and Rikenellaceae_RC9_gut_group. The LEfSe analysis revealed an enrichment of Sutterella and Akkermansia muciniphila. In conclusion, the results of this experiment indicated that the additional supplementation of MRY can improve the production performance of laying hens and may contribute to the restoration and balance of intestinal homeostasis, which supports the application potential of MRY as a green and efficient feed additive for improving the laying performance in chickens.

The regulation of glucose and lipid metabolism through the interaction of dietary polyphenols and polysaccharides via the gut microbiota pathway

The interaction of polyphenols-polysaccharides-gut microbiota to promote health benefits has become a hotspot and direction for precise dietary intervention strategies and foundational research in biomedicine. Both dietary polyphenols and polysaccharides possess biological activities that regulate body health. Single components, due to their inherent structure and physicochemical properties, have a low bioavailability, thus are unable to exert their optimal effects. The compound structure formed by the interaction of polyphenols and polysaccharides can enhance their functional properties, thereby more effectively promoting health benefits and preventing diseases. This review primarily focuses on the roles played by polyphenols and polysaccharides in regulating glucose and lipid metabolism, the improvement of glucose and lipid metabolism through the gut microbial pathway by polyphenols and polysaccharides, and the mechanisms by which polyphenols and polysaccharides interact to regulate glucose and lipid metabolism. A considerable amount of preliminary research has confirmed the regulatory effects of plant polyphenols and polysaccharides on glucose and lipid metabolism. However, studies on the combined effects and mechanisms of these two components are still very limited. This review aims to provide a reference for subsequent research on their interactions and changes in functional properties.

Impact of cholecystectomy on the gut-liver axis and metabolic disorders

Cholecystectomy is considered as a safe procedure to treat patients with gallstones. However, epidemiological studies highlighted an association between cholecystectomy and metabolic disorders, such as type 2 diabetes mellitus and metabolic dysfunction-associated steatotic liver disease (MASLD), independently of the gallstone disease. Following cholecystectomy, bile acids flow directly from the liver into the intestine, leading to changes in the entero-hepatic circulation of bile acids and their metabolism. The changes in bile acids metabolism impact the gut microbiota. Therefore, cholecystectomized patients display gut dysbiosis characterized by a reduced diversity, a loss of bacteria producing short-chain fatty acids and an increase in pro-inflammatory bacteria. Alterations of both bile acids metabolism and gut microbiota occurring after cholecystectomy can promote the development of metabolic disorders. In this review, we discuss the impact of cholecystectomy on bile acids and gut microbiota and its consequences on metabolic functions.

Interactive Effects of Arabinoxylan Oligosaccharides and Green Tea Polyphenols on Obesity Management and Gut Microbiota Modulation in High-Fat Diet-Fed Mice

Dietary fiber and polyphenols have been shown to possess antiobesity properties. However, their combined effects need further investigation. This study investigated the individual and combined effects of arabinoxylan oligosaccharides (AXOS) from rice bran and green tea polyphenols (GTP) in high-fat diet-induced obese mice. We found that the combination of AXOS and GTP (A + G) significantly reduced overall fat mass and improved lipid profiles, although the effects were not synergistic. AXOS and GTP regulated lipid metabolism in different tissues and exhibited counteractive effects on gut microbiota. AXOS decreased α diversity and promoted Bifidobacterium, with GTP counteracting these effects. In vitro fermentation confirmed that GTP counteracted AXOS-induced microbiota changes in a dose-dependent manner. This study highlights the potential of tailored combinations of dietary fiber and polyphenols to treat obesity while considering their complex microbial interplay.

Dietary polyphenols represent a phytotherapeutic alternative for gut dysbiosis associated neurodegeneration: A systematic review

Globally, neurodegeneration and cerebrovascular disease are common and growing causes of morbidity and mortality. Pathophysiology of this group of diseases encompasses various factors from oxidative stress to gut microbial dysbiosis. The study of the etiology and mechanisms of oxidative stress as well as gut dysbiosis-induced neurodegeneration in Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, autism spectrum disorder, and Huntington's disease has recently received a lot of attention. Numerous studies lend credence to the notion that changes in the intestinal microbiota and enteric neuroimmune system have an impact on the initiation and severity of these diseases. The prebiotic role of polyphenols can influence the makeup of the gut microbiota in neurodegenerative disorders by modulating intracellular signalling pathways. Metabolites of polyphenols function directly as neurotransmitters by crossing the blood-brain barrier or indirectly via influencing the cerebrovascular system. This assessment aims to bring forth an interlink between the consumption of polyphenols biotransformed by gut microbiota which in turn modulate the gut microbial diversity and biochemical changes in the brain. This systematic review will further augment research towards the association of dietary polyphenols in the management of gut dysbiosis-associated neurodegenerative diseases.

Unveiling the Immunomodulatory Potential of Phenolic Compounds in Food Allergies

Food allergies are becoming ever more prevalent around the world. This pathology is characterized by the breakdown of oral tolerance to ingested food allergens, resulting in allergic reactions in subsequent exposures. Due to the possible severity of the symptoms associated with this pathology, new approaches to prevent it and reduce associated symptoms are of utmost importance. In this framework, dietary phenolic compounds appear as a tool with a not fully explored potential. Some phenolic compounds have been pointed to with the ability to modulate food allergies and possibly reduce their symptoms. These compounds can modulate food allergies through many different mechanisms, such as altering the bioaccessibility and bioavailability of potentially immunogenic peptides, by modulating the human immune system and by modulating the composition of the human microbiome that resides in the oral cavity and the gastrointestinal tract. This review deepens the state-of-the-art of the modulation of these mechanisms by phenolic compounds. While this review shows clear evidence that dietary supplementation with foods rich in phenolic compounds might constitute a new approach to the management of food allergies, it also highlights the need for further research to delve into the mechanisms of action of these compounds and decipher systematic structure/activity relationships.

An Update on Prebiotics and on Their Health Effects

Prebiotic compounds were originally defined as "a nondigestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health"; however, a significant modulation of the definition was carried out in the consensus panel of The International Scientific Association for Probiotics and Prebiotics (ISAPP), and the last definition states that "prebiotics are substrates that are selectively utilized by host microorganisms conferring a health benefit". Health effects of prebiotics compounds attracted the interest of researchers, food companies and Regulatory Agencies, as inferred by the number of articles on Scopus for the keywords "prebiotic" and "health effects", that is ca. 2000, for the period January 2021-January 2024. Therefore, the aim of this paper is to contribute to the debate on these topics by offering an overview of existing knowledge and advances in this field. A literature search was performed for the period 2012-2023 and after the selection of the most relevant items, the attention was focused on seven conditions for which at least 8-10 different studies were found, namely colorectal cancer, neurological or psychiatric conditions, intestinal diseases, obesity, diabetes, metabolic syndrome, and immune system disorders. In addition, the analysis of the most recent articles through the software VosViewer version 1.6.20 pointed out the existence of five clusters or macro-categories, namely: (i) pathologies; (ii) metabolic condvitions; (iii) structure and use in food; (iv) immunomodulation; (v) effect on gut microbiota.

The Antiobesity Effects and Potential Mechanisms of Theaflavins

Theaflavins are the characteristic polyphenols in black tea which can be enzymatically synthesized. In this review, the effects and molecular mechanisms of theaflavins on obesity and its comorbidities, including dyslipidemia, insulin resistance, hepatic steatosis, and atherosclerosis, were summarized. Theaflavins ameliorate obesity potentially via reducing food intake, inhibiting pancreatic lipase to reduce lipid absorption, activating the adenosine monophosphate-activated protein kinase (AMPK), and regulating the gut microbiota. As to the comorbidities, theaflavins ameliorate hypercholesterolemia by inhibiting micelle formation to reduce cholesterol absorption. Theaflavins improve insulin sensitivity by increasing the signaling of protein kinase B, eliminating glucose toxicity, and inhibiting inflammation. Theaflavins ameliorate hepatic steatosis via activating AMPK. Theaflavins reduce atherosclerosis by upregulating nuclear factor erythropoietin-2-related factor 2 signaling and inhibiting plasminogen activator inhibitor 1. In randomized controlled trails, black tea extracts containing theaflavins reduced body weight in overweight people and improved glucose tolerance in healthy adults. The amelioration on the hyperlipidemia and the prevention of coronary artery disease by black tea extracts were supported by meta-analysis.

The intestinal-level metabolic benefits of green tea catechins: Mechanistic insights from pre-clinical and clinical studies

BACKGROUND

The intestinal-level host-microbiota interaction has been implicated in the pathogenesis of chronic diseases. The current review is intended to provide a comprehensive insight into deciphering whether intestinal-level bioactivities mediate the overall metabolic health benefits of green tea catechins.

PURPOSE

We have comprehensively discussed pre-clinical and clinical evidences of intestinal-level changes in metabolism, microbiota, and metabolome due to catechin-rich green tea treatments, ultimately limiting metabolic diseases. Exclusive emphasis has been given to purified catechins and green tea, and discussions on extraintestinal mechanisms of metabolic health benefits were avoided.

METHODS

A literature search for relevant pre-clinical and clinical studies was performed in various online databases (e.g., PubMed) using specific keywords (e.g., catechin, intestine, microbiota). Out of all the referred literature, ∼15% belonged to 2021-2023, ∼51% were from 2011-2020, and ∼32% from 2000-2010.

RESULT

The metabolic health benefits of green tea catechins are indeed influenced by the intestinal-level bioactivities, including reduction of mucosal inflammation and oxidative stress, attenuation of gut barrier dysfunction, decrease in intestinal lipid absorption and metabolism, favorable modulation of mucosal nuclear receptor signaling, alterations of the luminal global metabolome, and mitigation of the gut dysbiosis. The results from the recent clinical studies support the pre-clinical evidences. The challenges and pitfalls of the currently available knowledge on catechin bioactivities have been discussed, and constructive directions to harness the translational benefits of green tea through future interventions have been provided.

CONCLUSION

The metabolism, metabolome, and microbiota at the intestinal epithelia play critical roles in catechin metabolism, pharmacokinetics, bioavailability, and bioactivities. Especially the reciprocal interaction between the catechins and the gut microbiota dictates the metabolic benefits of catechins.

Anti-obesity activity of human gut microbiota Bacteroides stercoris KGMB02265

Obesity is a global health threat that causes various complications such as type 2 diabetes and nonalcoholic fatty liver disease. Gut microbiota is closely related to obesity. In particular, a higher Firmicutes to Bacteroidetes ratio has been reported as a biomarker of obesity, suggesting that the phylum Bacteroidetes may play a role in inhibiting obesity. Indeed, the genus Bacteroides was enriched in the healthy subjects based on metagenome analysis. In this study, we determined the effects of Bacteroides stercoris KGMB02265, a species belonging to the phylum Bacteroidetes, on obesity both in vitro and in vivo. The cell-free supernatant of B. stercoris KGMB02265 inhibited lipid accumulation in 3T3-L1 preadipocytes, in which the expression of adipogenic marker genes was repressed. In vivo study showed that the oral administration of B. stercoris KGMB02265 substantially reduced body weight and fat weight in high-fat diet induced obesity in mice. Furthermore, obese mice orally administered with B. stercoris KGMB02265 restored glucose sensitivity and reduced leptin and triglyceride levels. Taken together, our study reveals that B. stercoris KGMB02265 has anti-obesity activity and suggests that it may be a promising candidate for treating obesity.

Lowering glycemic levels via gastrointestinal tract factors: the roles of dietary fiber, polyphenols, and their combination

Dietary fiber (DF) and polyphenols (DP) are typical blood sugar-lowering components, and both play distinct yet interconnected roles in exerting their blood sugar-lowering effects. We comprehensively summarized the single and combined effects of DF and DP on blood glucose homeostasis through regulating the relevant factors in the upper gastrointestinal tract (UGT) and lower gastrointestinal tract (LGT). In the UGT, DF slowed down glucose metabolism by enhancing digesta viscosity and hindering enzyme-substrate interaction. DP primarily targeted enzymes and substrates. When combined, DP enhanced the adsorption capacity of DF for glucose. DF weakened DP's inhibitory effect on enzymes. Both DF and DP disrupted glucose intestinal uptake via physical or genomic modulation, but the co-consumption of DF and DP demonstrated a lower inhibitory effect on glucose uptake than DP alone. In the LGT, DF and DP showed synergistic or antagonistic effects on gut microbiota. Remarkably, whole foods exhibited potent prebiotic effects due to their compound-rich matrix, potentially enhancing glucose homeostasis and expanding dietary options for glucose regulation research.

Prebiotic effects of plant-derived (poly)phenols on host metabolism: Is there a role for short-chain fatty acids?

The gut microbiota has been extensively investigated during the last decade because of its effects on host neuroendocrine pathways and other processes. The imbalance between beneficial and pathogenic bacteria, known as dysbiosis, may be a determining predisposing factor for many noncommunicable chronic diseases, such as obesity, type 2 diabetes mellitus, metabolic syndrome, and Alzheimer's disease. On the other hand, interventions aiming to reestablish the balance between microbiota components have been suggested as potential preventive therapeutic strategies against these disorders. Among these interventions, dietary supplementation with (poly)phenols has been highlighted due to the modulatory effects exerted by those compounds on the gut microbiota. In addition, (poly)phenol consumption is associated with increased production of short-chain fatty acids (SCFAs), a set of microbial metabolites whose actions are ascribed to improving the abovementioned metabolic disorders. Thus, this review discusses the modulation of the gut microbiota by prebiotic (poly)phenols based on in vivo studies performed with isolated (poly)phenolic compounds, their interaction with the gut microbiota and the production of SCFAs in pursuit of the molecular mechanisms underlying the health effects of (poly)phenols on host metabolism.

Lactoferrin deficiency during lactation increases the risk of depressive-like behavior in adult mice

BACKGROUND

Lactoferrin is an active protein in breast milk that plays an important role in the growth and development of infants and is implicated as a neuroprotective agent. The incidence of depression is currently increasing, and it is unclear whether the lack of lactoferrin during lactation affects the incidence of depressive-like behavior in adulthood.

RESULTS

Lack of lactoferrin feeding during lactation affected the barrier and innate immune functions of the intestine, disrupted the intestinal microflora, and led to neuroimmune dysfunction and neurodevelopmental delay in the hippocampus. When exposed to external stimulation, adult lactoferrin feeding-deficient mice presented with worse depression-like symptoms; the mechanisms involved were activation of the LPS-TLR4 signalling pathway in the intestine and hippocampus, reduced BDNF-CREB signaling pathway in hippocampus, increased abundance of depression-related bacteria, and decreased abundance of beneficial bacteria.

CONCLUSIONS

Overall, our findings reveal that lactoferrin feeding deficient during lactation can increase the risk of depressive-like behavior in adults. The mechanism is related to the regulatory effect of lactoferrin on the development of the "microbial-intestinal-brain" axis.

Glutamine Ameliorates Liver Steatosis via Regulation of Glycolipid Metabolism and Gut Microbiota in High-Fat Diet-Induced Obese Mice

Obesity and its associated conditions, such as nonalcoholic fatty liver disease (NAFLD), are risk factors for health. The aim of this study was to explore the effects of glutamine (Gln) on liver steatosis induced by a high-fat diet (HFD) and HEPG2 cells induced by oleic acid. Gln demonstrated a positive influence on hepatic homeostasis by suppressing acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS) and promoting sirtuin 1 (SIRT1) expression while improving glucose metabolism by regulating serine/threonine protein kinase (AKT)/factor forkhead box O1 (FOXO1) signals in vivo and in vitro. Obese Gln-fed mice had higher colonic short-chain fatty acid (SCFA) contents and lower inflammation factor protein levels in the liver, HEPG2 cells, and jejunum. Gln-treated obese mice had an effective decrease in Firmicutes abundance. These findings indicate that Gln serves as a nutritional tool in managing obesity and related disorders.

The Effect of Theaflavins on the Gut Microbiome and Metabolites in Diabetic Mice

With the development of diabetes, the gut microbiome falls into a state of dysbiosis, further affecting its progression. Theaflavins (TFs), a type of tea polyphenol derivative, show anti-diabetic properties, but their effect on the gut microbiome in diabetic mice is unclear. It is unknown whether the improvement of TFs on hyperglycemia and hyperlipidemia in diabetic mice is related to gut microbiota. Therefore, in this study, different concentrations of TFs were intragastrically administered to mice with diabetes induced by a high-fat-diet to investigate their effects on blood glucose, blood lipid, and the gut microbiome in diabetic mice, and the plausible mechanism underlying improvement in diabetes was explored from the perspective of the gut microbiome. The results showed that the TFs intervention significantly improved the hyperglycemia and hyperlipidemia of diabetic mice and affected the structure of the gut microbiome by promoting the growth of bacteria positively related to diabetes and inhibiting those negatively related to diabetes. The changes in short-chain fatty acids in mice with diabetes and functional prediction analysis suggested that TFs may affect carbohydrate metabolism and lipid metabolism by regulating the gut microbiome. These findings emphasize the ability of TFs to shape the diversity and structure of the gut microbiome in mice with diabetes induced by a high-fat diet combined with streptozotocin and have practical implications for the development of functional foods with TFs.

Casein-phenol interactions occur during digestion and affect bioactive peptide and phenol bioaccessibility

Casein (CN) represents many proline residues that may bind polyphenols. Some evidence exists of CN-polyphenols interaction in model systems. The formation of such interactions upon digestion and the effects on CN digestibility and potential functionality due to the release of bioactive peptides are obscure. This study aimed to explore the interactions of CN with different phenol compounds under digestive conditions and monitor how they affect the bioaccessibility of phenol compounds and bioactive peptides. CN or CN hydrolysate and phenol compounds such as chlorogenic acid, ellagic acid, catechin, green tea extract, and tea extract, singularly or in combination with CN were digested in vitro. Total antioxidant capacity (TAC), degree of hydrolysis, and bioactive peptide formation were assessed in the samples collected through the digestion. The results showed that bioaccessible TAC was 1.17 to 1.93-fold higher in CN co-digested with phenol compounds than initially due to a higher release of antioxidant peptides in the presence of phenolic compounds. However, TAC values in the intestinal insoluble part of CN-phenol digests were higher than the initial, indicating that such interactions may be functional to transport phenols to the colon. Bioactive peptide release was affected by the phenol type (catechins were the most effective) as well as phenol concentration. As an opioid peptide released from β-CN, β-casomorphin formation was significantly influenced by the co-digestion of CN with phenol compounds. This study confirmed the possible CN-phenol interaction during digestion, affecting bioactive peptide release.

Health benefits, mechanisms of interaction with food components, and delivery of tea polyphenols: a review

Tea polyphenols (TPs) are the most important active component of tea and have become a research focus among natural products, thanks to their antioxidant, lipid-lowering, liver-protecting, anti-tumor, and other biological activities. Polyphenols can interact with other food components, such as protein, polysaccharides, lipids, and metal ions to further improve the texture, flavor, and sensory quality of food, and are widely used in food fields, such as food preservatives, antibacterial agents and food packaging. However, the instability of TPs under conditions such as light or heat and their low bioavailability in the gastrointestinal environment also hinder their application in food. In this review, we summarized the health benefits of TPs. In order to better use TPs in food, we analyzed the form and mechanism of interaction between TPs and main food components, such as polysaccharides and proteins. Moreover, we reviewed research into optimizing the applications of TPs in food by bio-based delivery systems, such as liposomes, nanoemulsions, and nanoparticles, so as to improve the stability and bioactivity of TPs in food application. As an effective active ingredient, TPs have great potential to be applied in functional food to produce benefits for human health.

The Role of Green Tea on the Regulation of Gut Microbes and Prevention of High-Fat Diet-Induced Metabolic Syndrome in Mice

Green tea is a popular non-alcoholic beverage consumed worldwide and has been shown to be beneficial for human health. However, further exploration is needed to fully understand its function in reducing obesity and regulating gut microbes. Here, we investigated the modulatory effects of green tea and its functional components on high-fat diet (HF)-induced metabolic alterations and gut microbiota in obese mice. Our results showed that 1%, 2%, and 4% of green tea promotes weight loss, with the 2% and 4% groups exhibiting distinct gut microflora clusters compared to the HF group. These results were comparable to those observed in the tea polyphenols (TPP)-treated group, suggesting the TPP in green tea plays a crucial role in body weight control and gut microbiota regulation. Additionally, 32 bacteria were identified as potential obesity markers via 16S rRNA gene sequencing. The 16SrDNA gene is a chromosomal gene present in all bacterial species, highly conserved in structure and function, that can reflect the differences between different taxa. The 16S rRNA-based analysis revealed that Akkermansia, a gut-beneficial bacteria, significantly increased in the TPP group.

Pectin alleviates the pulmonary inflammatory response induced by PM2.5 from a pig house by modulating intestinal microbiota

This study aimed to investigate whether dietary fiber pectin can alleviate PM_2.5-induced pulmonary inflammation and the potential mechanism. PM_2.5 samples were collected from a nursery pig house. The mice were divided into three groups: the control group, PM_2.5 group and PM_2.5 + pectin group. The mice in the PM_2.5 group were intratracheally instilled with PM_2.5 suspension twice a week for four consecutive weeks, and those in the PM_2.5 + pectin group were subject to the same PM_2.5 exposure, but fed with a basal diet supplemented with 5% pectin. The results showed that body weight and feed intake were not different among the treatments (p > 0.05). However, supplementation with pectin relieved PM_2.5-induced pulmonary inflammation, presenting as slightly restored lung morphology, decreased mRNA expression levels of IL-1β, IL-6 and IL-17 in the lung, decreased MPO content in bronchoalveolar lavage fluid (BLAF), and even decreased protein levels of IL-1β and IL-6 in the serum (p < 0.05). Dietary pectin altered the composition of the intestinal microbiota, increasing the relative abundance of Bacteroidetes and decreasing the ratio of Firmicutes/Bacteroidetes. At the genus level, short-chain fatty acid (SCFA)-producing bacteria, such as Bacteroides, Anaerotruncus, Prevotella 2, Parabacteroides, Ruminococcus 2 and Butyricimonas, were enriched in the PM_2.5 +pectin group. Accordingly, dietary pectin increased the concentrations of SCFAs, including acetate, propionate, butyrate and valerate, in mice. In conclusion, dietary fermentable fiber pectin can relieve PM_2.5-induced pulmonary inflammation via alteration of intestinal microbiota composition and SCFA production. This study provides a new insight into reducing the health risk associated with PM_2.5 exposure.

Gut microbiome-mediated mechanisms in aging-related diseases: are probiotics ready for prime time?

Chronic low-grade inflammation affects health and is associated with aging and age-related diseases. Dysregulation of the gut flora is an important trigger for chronic low-grade inflammation. Changes in the composition of the gut flora and exposure to related metabolites have an effect on the inflammatory system of the host. This results in the development of crosstalk between the gut barrier and immune system, contributing to chronic low-grade inflammation and impairment of health. Probiotics can increase the diversity of gut microbiota, protect the gut barrier, and regulate gut immunity, thereby reducing inflammation. Therefore, the use of probiotics is a promising strategy for the beneficial immunomodulation and protection of the gut barrier through gut microbiota. These processes might positively influence inflammatory diseases, which are common in the elderly.

Gut microbiota-mediated associations of green tea and catechin intakes with glucose metabolism in individuals without type 2 diabetes mellitus: a four-season observational study with mediation analysis

This four-season observational study aimed to examine the mediating role of the gut microbiota in the associations between green tea and catechin intakes and glucose metabolism in individuals without type 2 diabetes mellitus (T2DM). In each of the 4 seasons, 85 individuals without T2DM (56 male [65.9%]; mean [standard deviation] age: 43.3 [9.4] years) provided blood samples, stool samples, 3-day weighed dietary records, and green tea samples. Catechin intake was estimated by analyzing the tea samples. Linear mixed-effects model analysis showed that green tea intake was negatively associated with fasting blood glucose and insulin levels, even after considering the seasonal variations. Of the gut microbial species associated with green tea intake, the mediation analysis revealed that Phocaeicola vulgatus mediated the association between green tea intake and fasting blood glucose levels. These findings indicate that green tea can improve glucose metabolism by decreasing the abundance of P. vulgatus that is associated with elevated blood glucose levels in individuals without T2DM.

Integrated 16S rDNA sequencing and metabolomics to explore the intestinal changes in children and rats with dental fluorosis

Dental fluorosis (DF) is a widely prevalent disease caused by excessive fluoride with limited awareness of its underlying pathogenesis. Here, a pilot population study was conducted to explore the pathogenesis of DF from the perspective of intestinal microbiome changes, and verified it in animal experiments combining intestinal microbiome and metabolomics. A total of 23 children were recruited in 2017 in China and divided into DF (n = 9) and control (n = 14) groups (DFG and CG, respectively). The SD rat model was established by drinking water containing sodium fluoride (NaF). Gut microbiome profiles of children and rats were analyzed by16S rDNA V3-V4 sequencing, and the intestinal metabolomics analysis of rats was performed by LC-MS methods. The 16 S rDNA sequencing revealed that the gut microbiome composition was significantly perturbed in children in DFG compared to that in CG. Acidobacteria and Thermi were specifically observed in DFG and CG, respectively. Besides, 15 fecal microbiotas were significantly altered at the genus level in DFG. Furthermore, only the expression of annotated genes for pentose and glucuronate interconversion pathway was significant lower in DFG than that in CG (P = 0.04). Notably, in NaF-treated rats, we also observed the changes of some key components of pentose and glucuronate interconversion pathway at the level of microorganisms and metabolites. Our findings suggested that the occurrence of DF is closely related to the alteration of intestinal microorganisms and metabolites annotated in the pentose and glucuronate interconversion pathway.

Research progress on the lipid-lowering and weight loss effects of tea and the mechanism of its functional components

Obesity caused by poor eating habits has become a great challenge faced by public health organizations worldwide. Optimizing dietary intake and ingesting special foods containing biologically active substances (such as polyphenols, alkaloids, and terpenes) is a safe and effective dietary intervention to prevent the occurrence and development of obesity. Tea contains several active dietary factors, and daily tea consumption has been shown to have various health benefits, especially in regulating human metabolic diseases. Here, we reviewed recent advances in research on tea and its functional components in improving obesity-related metabolic dysfunction, and gut microbiota homeostasis and related clinical research. Furthermore, the potential mechanisms by which the functional components of tea could promote lipid-lowering and weight-loss effects by regulating fat synthesis/metabolism, glucose metabolism, gut microbial homeostasis, and liver function were summarized. The research results showing a "positive effect" or "no effect" objectively evaluates the lipid-lowering and weight-loss effects of the functional components of tea. This review provides a new scientific basis for further research on the functional ingredients of tea for lipid lowering and weight loss and the development of lipid-lowering and weight-loss functional foods and beverages derived from tea.

Anti-Inflammatory, Antioxidant, and Neuroprotective Effects of Polyphenols-Polyphenols as an Element of Diet Therapy in Depressive Disorders

Depressive disorders can affect up to 350 million people worldwide, and in developed countries, the percentage of patients with depressive disorders may be as high as 10%. During depression, activation of pro-inflammatory pathways, mitochondrial dysfunction, increased markers of oxidative stress, and a reduction in the antioxidant effectiveness of the body are observed. It is estimated that approximately 30% of depressed patients do not respond to traditional pharmacological treatments. However, more and more attention is being paid to the influence of active ingredients in food on the course and risk of neurological disorders, including depression. The possibility of using foods containing polyphenols as an element of diet therapy in depression was analyzed in the review. The possibility of whether the consumption of products such as polyphenols could alleviate the course of depression or prevent the progression of it was also considered. Results from preclinical studies demonstrate the potential of phenolic compounds have the potential to reduce depressive behaviors by regulating factors related to oxidative stress, neuroinflammation, and modulation of the intestinal microbiota.

Intestinal flora: A new target for traditional Chinese medicine to improve lipid metabolism disorders

Lipid metabolism disorders (LMD) can cause a series of metabolic diseases, including hyperlipidemia, obesity, non-alcoholic fatty liver disease (NAFLD) and atherosclerosis (AS). Its development is caused by more pathogenic factors, among which intestinal flora dysbiosis is considered to be an important pathogenic mechanism of LMD. In recent years, the research on intestinal flora has made great progress, opening up new perspectives on the occurrence and therapeutic effects of diseases. With its complex composition and wide range of targets, traditional Chinese medicine (TCM) is widely used to prevent and treat LMD. This review takes intestinal flora as a target, elaborates on the scientific connotation of TCM in the treatment of LMD, updates the therapeutic thinking of LMD, and provides a reference for clinical diagnosis and treatment.

Tea Consumption and Gut Microbiome in Older Chinese Adults

BACKGROUND

Animal and small-cohort human studies have shown that tea consumption affects the gut microbiome, but evidence from large cohort studies is lacking.

OBJECTIVES

We examined associations between tea consumption and gut microbiome composition among older Chinese adults.

METHODS

The study included 1179 men and 1078 women from the Shanghai Men's and Women's Health Studies, who reported tea drinking status, type, amount, and duration at baseline and follow-up surveys (1996-2017) and were free of cancer, cardiovascular disease, and diabetes at stool collection (2015-2018). Fecal microbiome was profiled using 16S rRNA sequencing. Associations of tea variables with microbiome diversity and taxa abundance were evaluated using linear or negative binomial hurdle models after adjusting for sociodemographics, lifestyle, and hypertension status.

RESULTS

Mean age at stool collection was 67.2 ± 9.0 y in men and 69.6 ± 8.5 y in women. Tea drinking was not associated with microbiome ɑ-diversity in men or women; however, all tea variables were associated with β-diversity in men (P < 0.001). Significant associations with taxa abundance were also observed mostly in men. Current tea drinking, mainly green tea drinking, was associated with increase in orders Synergistales and RF39 in men (β = 0.30 to 0.42, all PFDR ≤ 0.10) but not in women (PInteraction-sex = 0.01). Also, increase in families Coriobacteriaceae, Odoribacteraceae, genera Collinsella, Odoribacter, and species Collinsella aerofaciens, Coprococcus catus, and Dorea formicigenerans were observed among men who drank >3.3 cups (781 mL)/d compared to that of nondrinkers (all PFDR <0.10). The increased Coprococcus catus related to tea drinking was more evident among men without hypertension and inversely associated with the prevalence of hypertension (OR: 0.90; 95% CI: 0.84, 0.97; PFDR = 0.03).

CONCLUSIONS

Tea consumption may affect gut microbiome β-diversity and abundance of some bacteria, which may contribute to reduced hypertension risk in Chinese men. Future studies should examine the sex-specific tea-gut microbiome associations and how certain bacteria may mediate the health benefits of tea.

Tea Plant (Camellia sinensis): A Current Update on Use in Diabetes, Obesity, and Cardiovascular Disease

The tea plant (C. sinensis) has traditionally been consumed worldwide as "tea" for its many health benefits, with the potential for the prevention and therapy of various conditions. Regardless of its long history, the use of tea plants in modern times seems not to have changed much, as the beverage remains the most popular form. This review aimed to compile scientific information about the role and action of tea plants, as well as their status concerning clinical applications, based on the currently available evidence, with a focus on metabolic syndrome, mainly covering obesity, diabetes, and cardiovascular disease. It has been recognized that these diseases pose a significant threat to public health, and the development of effective treatment and prevention strategies is necessary but still challenging. In this article, the potential benefits of tea plants and their derived bioactive components (such as epigallocatechin-3-gallate) as anti-obesity, anti-diabetic, and anti-cardiovascular agents are clearly shown and emphasized, along with their mechanisms of action. However, according to the status of the clinical translation of tea plants, particularly in drug development, more substantial efforts in well-designed, randomized, controlled trials are required to expand their applications in treating the three major metabolic disorders and avoiding the toxicity caused by overconsumption.

Arazyme in combination with dietary carbohydrolases influences odor emission and gut microbiome in growing-finishing pigs

This study evaluated the effects of supplementing feed with arazyme and dietary carbohydrolases derived from invertebrate gut-associated symbionts on the noxious gas emissions, gut microbiota, and host-microbiome interactions of pigs. Here, 270 and 260 growing pigs were assigned to control and treatment groups, respectively. The tested feed additives contained a mixture of arazyme (2,500,000 Unit/kg) and synergetic enzymes, xylanase (200,000 Unit/kg) and mannanase (200,000 Unit/kg), derived from insect gut-associated symbionts in a 7.5:1:1 ratio. The control group was fed a basal diet and the treatment group was fed the basal diet supplemented with 0.1 % enzyme mixture (v/v) for 2 months. Odorous gases were monitored in ventilated air from tested houses. Fecal samples were collected from steel plate under the cage at the completion of the experiment to determine chemical composition, odor emissions, and bacterial communities. There was a significant decrease in the concentration of NH₃ (22.5 vs. 11.2 ppm; P < 0.05), H₂S (7.35 vs. 3.74 ppm; P < 0.05), trimethylamine (TMA) (0.066 vs. 0.001 ppm; P < 0.05), and p-cresol (0.004 ppm vs. 0 ppm; P < 0.05) at 56 d in treatment group compared with the control group. Moreover, fecal analysis results showed that exogenous enzyme supplementation caused a reduction in VFAs and indole content with approximately >60 % and 72.7 %, respectively. The result of gas emission analysis showed that NH₃ (9.9 vs. 5.3 ppm; P < 0.05) and H₂S (5.8 vs. 4.1 ppm; P < 0.05) were significantly reduced in the treatment group compared to the control group. The gut microbiota of the treatment group differed significantly from that of the control group, and the treatment group altered predicted metabolic pathways, including sulfur and nitrogen related metabolism, urea degradation. The results demonstrated that supplementing feed with arazyme with dietary carbohydrolases effectively controls noxious gas emissions and improves health and meat quality of pigs.

Dietary Polyphenols as Prospective Natural-Compound Depression Treatment from the Perspective of Intestinal Microbiota Regulation

The broad beneficial effects of dietary polyphenols on human health have been confirmed. Current studies have shown that dietary polyphenols are important for maintaining the homeostasis of the intestinal microenvironment. Moreover, the corresponding metabolites of dietary polyphenols can effectively regulate intestinal micro-ecology and promote human health. Although the pathogenesis of depression has not been fully studied, it has been demonstrated that dysfunction of the microbiota-gut-brain axis may be its main pathological basis. This review discusses the interaction between dietary polyphenols and intestinal microbiota to allow us to better assess the potential preventive effects of dietary polyphenols on depression by modulating the host gut microbiota.

What is the role of phenolic compounds of yerba mate (Ilex paraguariensis) in gut microbiota?

Diet actively influences gut microbiota and body homeostasis. The predominance of beneficial species results in symbiosis, while dysbiosis is characterized by an imbalance between microbial communities. Food plays a key role in this dynamic and in promoting the health of individuals. Ilex paraguariensis, also known as yerba mate, is a traditional plant from Latin America that has a complex matrix of bioactive substances, including methylxanthines, triterpenes, saponins, and phenolics. The consumption of yerba mate is associated with antioxidant, cardioprotective, anti-inflammatory, and anti-obesity effects. However, to the best of our knowledge, there have been no studies on yerba mate as a modulating agent of intestinal microbiota. Phenolics are the major compounds in yerba mate and have been reported to act in modulating the microbiome. In this review, we explore the activity of yerba mate as a possible stimulant of gut microbiota and present its main phenolics and their biological effects. We also propose different mechanisms of action of these phenolics and possible doses for their effectiveness.

Capsaicin Ameliorates High-Fat Diet-Induced Atherosclerosis in ApoE−/− Mice via Remodeling Gut Microbiota

Capsaicin is a pungent alkaloid abundantly present in peppers with outstanding biological activities, including the anti-atherosclerosis effect. Previous studies revealed that gut microbiota played an important role in the beneficial effects of capsaicin, but whether it is essential for the anti-atherosclerosis effect of capsaicin is unclear. This study evaluated the anti-atherosclerosis effect of capsaicin in ApoE^−/− mice and further explored the role of depleting gut microbiota in the improvement of atherosclerosis. The results showed that capsaicin administration could prevent the development of atherosclerosis and improve serum lipids and inflammation, while antibiotic intervention abolished the alleviation of atherosclerosis by capsaicin. In addition, capsaicin administration could significantly increase the abundance of Turicibacter, Odoribacter, and Ileibacterium in feces, and decrease the abundance of deoxycholic acid, cholic acid, hypoxanthine, and stercobilin in cecal content. Our study provides evidence that gut microbiota plays a critical role in the anti-atherosclerosis effect of capsaicin.

Allergic Inflammation: Effect of Propolis and Its Flavonoids

The incidence of allergic diseases and their complications are increasing worldwide. Today, people increasingly use natural products, which has been termed a "return to nature". Natural products with healing properties, especially those obtained from plants and bees, have been used in the prevention and treatment of numerous chronic diseases, including allergy and/or inflammation. Propolis is a multi-component resin rich in flavonoids, collected and transformed by honeybees from buds and plant wounds for the construction and adaptation of their nests. This article describes the current views regarding the possible mechanisms and multiple benefits of flavonoids in combating allergy and allergy-related complications. These benefits arise from flavonoid anti-allergic, anti-inflammatory, antioxidative, and wound healing activities and their effects on microbe-immune system interactions in developing host responses to different allergens. Finally, this article presents various aspects of allergy pathobiology and possible molecular approaches in their treatment. Possible mechanisms regarding the antiallergic action of propolis on the microbiota of the digestive and respiratory tracts and skin diseases as a method to selectively remove allergenic molecules by the process of bacterial biotransformation are also reported.

New Insights on the Role of Bioactive Food Derivatives in Neurodegeneration and Neuroprotection

Over the last three decades, neurodegenerative diseases have received increasing attention due to their frequency in the aging population and the social and economic burdens they are posing. In parallel, an era's worth of research in neuroscience has shaped our current appreciation of the complex relationship between nutrition and the central nervous system. Particular branches of nutrition continue to galvanize neuroscientists, in particular the diverse roles that bioactive food derivatives play on health and disease. Bioactive food derivatives are nowadays recognized to directly impact brain homeostasis, specifically with respect to their actions on cellular mechanisms of oxidative stress, neuroinflammation, mitochondrial dysfunction, apoptosis and autophagy. However, ambiguities still exist regarding the significance of the influence of bioactive food derivatives on human health. In turn, gut microbiota dysbiosis is emerging as a novel player in the pathogenesis of neurodegenerative diseases. Currently, several routes of communication exist between the gut and the brain, where molecules are either released in the bloodstream or directly transported to the CNS. As such, bioactive food derivatives can modulate the complex ecosystem of the gut-brain axis, thus, targeting this communication network holds promises as a neuroprotective tool. This review aims at addressing one of the emerging aspects of neuroscience, particularly the interplay between food bioactive derivatives and neurodegeneration. We will specifically address the role that polyphenols and omega-3 fatty acids play in preventing neurodegenerative diseases and how dietary intervention complements available pharmacological approaches.

Characteristics of the Gut Microbiota in Japanese Patients with Premenstrual Syndrome

Purpose

The present study aimed to characterize the gut microbiota of individuals with premenstrual syndrome.

Patients and Methods

The gut microbiota of 24 Japanese women with PMS (PMS group) and 144 healthy Japanese women (control group) were compared. Analysis of the α- and β-diversities and the gut microbial composition at the genus level were performed using 16S rRNA gene sequence data obtained from stool samples.

Results

A significant difference in age was observed between the PMS and control groups; however, no significant difference was observed in BMI. The α-diversity measured using the Simpson index was significantly higher in the PMS group than the control group. Visualization of the β-diversity using non-metric multidimensional scaling and permutational multivariate analysis of variance (PERMANOVA) showed that the distance of the gut microbiota between the PMS and control groups is significantly different. Furthermore, a significant difference in the composition of the gut microbiota was observed between the PMS and control groups. At the genus level, the abundances of Collinsella, Bifidobacterium, and Blautia were significantly higher in the PMS group than in the control group. In particular, the abundance of Collinsella in the PMS group was approximately 4.5 times higher than that in the control group. To rule out the confounding effect of age in the abundances of Bifidobacterium, Blautia, and Collinsella, the gut microbiota of the PMS and control groups were compared by age group. Results showed that Collinsella had the highest effect size in participants of 30–40 years of age (mean age: 36.39 ± 4.68 years).

Conclusion

These results suggest that the PMS group possesses a characteristic gut microbiota. In particular, Collinsella was strongly associated with PMS. Since Collinsella has been reported to be associated with diet, dietary interventions such as prebiotics targeting Collinsella may be effective in preventing, improving, and alleviating PMS.

Identification of a novel probiotic and its protective effects on NAFLD via modulating gut microbial community

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is becoming the most common progressive liver diseases. Therapeutic strategy based on gut-liver axis and probiotics is a promising approach for the treatment of NAFLD. However, rare probiotics have been applied in NAFLD treatment, and the involved molecular mechanism is not entirely clear.

RESULTS

We initially identified a novel functional probiotic, Lactobacillus kefiranofaciens ZW3, on the lipid deposition by a simple and rapid zebrafish model. Supplementation with ZW3 to the methionine and choline deficient (MCD) diet induced NAFLD rats could improve the liver impairments and reduce inflammation through TLR4-MyD88 and JNK signaling pathways. Moreover, ZW3 modulated gut microbiota by promoting relative abundance of Firmicutes and Lactobacillus, decreasing the abundance of Escherichia-Shigella and Bacteroides. Functional prediction of microbiome showed ZW3 presented potential enhancement on carbohydrate and lipid metabolism, cell process control and signal transduction processes, and reduced several human diseases.

CONCLUSION

This present study identified a novel probiotic and its protective effects on NAFLD, and interpreted the interactions of ZW3 with the immune system and gut microbiota involved in gut-liver axis. © 2022 Society of Chemical Industry.

Modulation of the gut microbiota and lipidomic profiles by black chokeberry (Aronia melanocarpa L.) polyphenols via the glycerophospholipid metabolism signaling pathway

Black chokeberry (Aronia melanocarpa L.) is rich in polyphenols with various physiological and pharmacological activities. However, the relationship between the modulation effect of black chokeberry polyphenols on obesity and the alteration of lipid metabolism is not clearly understood. This study aimed to investigate the beneficial effects of the black chokeberry polyphenols (BCPs) treatment on the structure of gut microbiota, lipid metabolism, and associated mechanisms in high-fat diet (HFD)-induced obese rats. Here, we found that a high-fat diet promoted body weight gain and lipid accumulation in rats, while oral BCPs supplementation reduced body weight, liver, and white adipose tissue weight and alleviated dyslipidemia and hepatic steatosis in HFD-induced obese rats. In addition, BCPs supplementation prevented gut microbiota dysbiosis by increasing the relative abundance of Bacteroides, Prevotella, Romboutsia, and Akkermansia and decreasing the relative abundance of Desulfovibrio and Clostridium. Furthermore, 64 lipids were identified as potential lipid biomarkers through lipidomics analysis after BCPs supplementation, especially PE (16:0/22:6), PE (18:0/22:6), PC (20:3/19:0), LysoPE (24:0), LysoPE (24:1), and LysoPC (20:0). Moreover, our studies provided new evidence that composition of gut microbiota was closely related to the alteration of lipid profiles after BCPs supplementation. Additionally, BCPs treatment could ameliorate the disorder of lipid metabolism by regulating the mRNA and protein expression of genes related to the glycerophospholipid metabolism signaling pathway in HFD-induced obese rats. The mRNA and protein expression of PPARα, CPT1α, EPT1, and LCAT were significantly altered after BCPs treatment. In conclusion, the results of this study indicated that BCPs treatment alleviated HFD-induced obesity by modulating the composition and function of gut microbiota and improving the lipid metabolism disorder via the glycerophospholipid metabolism signaling pathway.

The Role of Gut Microbiota Modulation Strategies in Obesity: The Applications and Mechanisms

Nowadays, obesity is a leading public health problem worldwide. The growing prevalence of obesity significantly accounts for other cardio-metabolic diseases, including hypertension and diabetes. Several studies have shown that obesity is strongly associated with genetic, environmental, lifestyle, and dietary factors, especially the disordered profiles of gut microbiota (GM). The present review concluded mechanistic studies and potential correspondent treatments for obesity. Specifically, the anti-obesity effects of food-derived compounds manipulating GM were highlighted. The potential limitations of bioactive compounds on absorption in the intestinal tract were also discussed. Thus, the future direction of fecal microbiota transplantation (FMT) as an approach to support modulating host GM (considered to be a potential therapeutic target for obesity) was discussed. This review shed light on the role of GM modulation strategies for the prevention/treatment of obesity.

Gut Microbiota Patterns Predicting Long-Term Weight Loss Success in Individuals with Obesity Undergoing Nonsurgical Therapy

Background: The long-term success of nonsurgical weight reduction programs is variable; thus, predictors of outcome are of major interest. We hypothesized that the intestinal microbiota known to be linked with diet and obesity contain such predictive elements. Methods: Metagenome analysis by shotgun sequencing of stool DNA was performed in a cohort of 15 adults with obesity (mean body mass index 43.1 kg/m²) who underwent a one-year multidisciplinary weight loss program and another year of follow-up. Eight individuals were persistently successful (mean relative weight loss 18.2%), and seven individuals were not successful (0.2%). The relationship between relative abundancies of bacterial genera/species and changes in relative weight loss or body mass index was studied using three different statistical modeling methods. Results: When combining the predictor variables selected by the applied statistical modeling, we identified seven bacterial genera and eight bacterial species as candidates for predicting success of weight loss. By classification of relative weight-loss predictions for each patient using 2–5 term models, 13 or 14 out of 15 individuals were predicted correctly. Conclusions: Our data strongly suggest that gut microbiota patterns allow individual prediction of long-term weight loss success. Prediction accuracy seems to be high but needs confirmation by larger prospective trials.

Tea (Camellia sinensis) Ameliorates Hyperuricemia via Uric Acid Metabolic Pathways and Gut Microbiota

Hyperuricemia (HUA) is a metabolic disease that threatens human health. Tea is a healthy beverage with an abundance of benefits. This study revealed the uric acid-lowering efficacy of six types of tea water extracts (TWEs) on HUA in mice. The results revealed that under the intervention of TWEs, the expression of XDH, a key enzyme that produces uric acid, was significantly downregulated in the liver. TWE treatment significantly upregulated the expression of uric acid secretion transporters ABCG2, OAT1, and OAT3, and downregulated the expression of uric acid reabsorption transporter URAT1 in the kidney. Furthermore, HUA-induced oxidative stress could be alleviated by upregulating the Nrf2/HO-1 pathway. The intervention of TWEs also significantly upregulated the expression of the intestinal ABCG2 protein. On the other hand, TWE intervention could significantly upregulate the expression of intestinal ABCG2 and alleviate HUA by modulating the gut microbiota. Taken together, tea can comprehensively regulate uric acid metabolism in HUA mice. Interestingly, we found that the degree of fermentation of tea was negatively correlated with the uric acid-lowering effect. The current study indicated that tea consumption may have a mitigating effect on the HUA population and provided a basis for further research on the efficacy of tea on the dosage and mechanism of uric acid-lowering effects in humans.

The Role of Nutritional Factors in the Modulation of the Composition of the Gut Microbiota in People with Autoimmune Diabetes

Type 1 diabetes mellitus (T1DM) is a disease marked by oxidative stress, chronic inflammation, and the presence of autoantibodies. The gut microbiota has been shown to be involved in the alleviation of oxidative stress and inflammation as well as strengthening immunity, thus its' possible involvement in the pathogenesis of T1DM has been highlighted. The goal of the present study is to analyze information on the relationship between the structure of the intestinal microbiome and the occurrence of T1DM. The modification of the intestinal microbiota can increase the proportion of SCFA-producing bacteria, which could in turn be effective in the prevention and/or treatment of T1DM. The increased daily intake of soluble and non-soluble fibers, as well as the inclusion of pro-biotics, prebiotics, herbs, spices, and teas that are sources of phytobiotics, in the diet, could be important in improving the composition and activity of the microbiota and thus in the prevention of metabolic disorders. Understanding how the microbiota interacts with immune cells to create immune tolerance could enable the development of new therapeutic strategies for T1DM and improve the quality of life of people with T1DM.

Nutrition-wide association study of microbiome diversity and composition in colorectal cancer patients

BACKGROUND

The effects of diet on the interaction between microbes and host health have been widely studied. However, its effects on the gut microbiota of patients with colorectal cancer (CRC) have not been elucidated. This study aimed to investigate the association between diet and the overall diversity and different taxa levels of the gut microbiota in CRC patients via the nutrition-wide association approach.

METHODS

This hospital-based study utilized data of 115 CRC patients who underwent CRC surgery in Department of Surgery, Seoul National University Hospital. Spearman correlation analyses were conducted for 216 dietary features and three alpha-diversity indices, Firmicutes/Bacteroidetes ratio, and relative abundance of 439 gut microbial taxonomy. To identify main enterotypes of the gut microbiota, we performed the principal coordinate analysis based on the β-diversity index. Finally, we performed linear regression to examine the association between dietary intake and main microbiome features, and linear discriminant analysis effect size (LEfSe) to identify bacterial taxa phylogenetically enriched in the low and high diet consumption groups.

RESULTS

Several bacteria were enriched in patients with higher consumption of mature pumpkin/pumpkin juice (ρ, 0.31 to 0.41) but lower intake of eggs (ρ, -0.32 to -0.26). We observed negative correlations between Bacteroides fragilis abundance and intake of pork (belly), beef soup with vegetables, animal fat, and fatty acids (ρ, -0.34 to -0.27); an inverse correlation was also observed between Clostridium symbiosum abundance and intake of some fatty acids, amines, and amino acids (ρ, -0.30 to -0.24). Furthermore, high intake of seaweed was associated with a 6% (95% CI, 2% to 11%) and 7% (95% CI, 2% to 11%) lower abundance of Rikenellaceae and Alistipes, respectively, whereas overall beverage consumption was associated with an 10% (95% CI, 2% to 18%) higher abundance of Bacteroidetes, Bacteroidia, and Bacteroidales, compared to that in the low intake group. LEfSe analysis identified phylogenetically enriched taxa associated with the intake of sugars and sweets, legumes, mushrooms, eggs, oils and fats, plant fat, carbohydrates, and monounsaturated fatty acids.

CONCLUSIONS

Our data elucidates the diet-microbe interactions in CRC patients. Additional research is needed to understand the significance of these results in CRC prognosis.

Hawk tea prevents high-fat diet-induced obesity in mice by activating the AMPK/ACC/SREBP1c signaling pathways and regulating the gut microbiota

Scope: Hawk tea, a non-Camellia tea, is an ancient tea drink from southwest China and has been proven to exhibit significant hypoglycaemic and lipid-lowering effects. The aim of this study was to evaluate whether Hawk tea extract (HTE) can improve obesity induced by a high-fat diet (HFD) in a mouse model and to determine whether its anti-obesity effects are related to improvements in lipid metabolism and the gut microbiota. Methods and results: We tested the ability of HTE to prevent obesity and regulate gut microbiota in C57BL/6J mice fed with a HFD. We found that HTE significantly reduced body weight, fat deposition, serum triglyceride (TG), total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels, and significantly increased serum levels of high-density lipoprotein cholesterol (HDL-C) induced by HFD. HTE also increased the levels of AMPK and ACC phosphorylation, up-regulated the expression of CPT-1, and downregulated the expression of SREBP1c and FAS. In addition, the administration of HTE significantly altered the composition of the gut microbiota, reduced the ratio of Firmicutes to Bacteroidetes, increased the relative abundance of Akkermansia muciniphila, Bacteroides-vulgatus, and Faecalibaculum_rodentium, and decreased the relative abundance of Desulfovibrionaceae and Lachnospiraceae. Conclusions: Collectively, our data demonstrate that HTE can prevent HFD-induced obesity by regulating the AMPK/ACC/SREBP1c signaling pathways and the gut microbiota.

Edible plant by-products as source of polyphenols: prebiotic effect and analytical methods

Polyphenols with high chemical diversity are present in vegetables both in the edible parts and by-products. A large proportion of them remains unabsorbed along the gastrointestinal tract, being accumulated in the colon, where they are metabolized by the intestinal microbiota. These polyphenols have been found to have "prebiotic-like" effects. The edible plant industry generates tons of residues called by-products, which consist of unutilized plant tissues (peels, husks, calyxes and seeds). Their disposal requires special and costly treatments to avoid environmental complications. Reintroducing these by-products into the value chain using technological and biotechnological practices is highly appealing since many of them contain nutrients and bioactive compounds, such as polyphenols, with many health-promoting properties. Edible plant by-products as a source of polyphenols highlights the need for analytical methods. Analytical methods are becoming increasingly selective, sensitive and precise, but the great breakthrough lies in the pretreatment of the sample and in particular in the extraction methods. This review shows the importance of edible plant by-products as a source of polyphenols, due to their prebiotic effect, and to compile the most appropriate analytical methods for the determination of the total content of phenolic compounds as well as the detection and quantification of individual polyphenols.

Large Yellow Tea Extract Ameliorates Metabolic Syndrome by Suppressing Lipogenesis through SIRT6/SREBP1 Pathway and Modulating Microbiota in Leptin Receptor Knockout Rats

Metabolic syndrome is a chronic metabolic disorder that has turned into a severe health problem worldwide. A previous study reported that large yellow tea exhibited better anti-diabetic and lipid-lowering effects than green tea. Nevertheless, the potential mechanisms are not yet understood. In this study, we examined the prevention effects and mechanisms of large yellow tea water extract (LWE) on metabolic syndrome using leptin receptor knockout (Lepr−/−) rats. Seven-week-old male Lepr−/− and wild type (WT) littermate rats were divided into Lepr−/− control group (KO) (n = 5), Lepr−/− with LWE-treated group (KL) (n = 5), WT control group (WT) (n = 6), and WT with LWE intervention group (WL) (n = 6). Then, the rats were administered water or LWE (700 mg/kg BW) daily by oral gavage for 24 weeks, respectively. The results showed that the administration of LWE significantly reduced the serum concentrations of random blood glucose, total cholesterol, triglyceride, and free fatty acids, and increased glucose tolerance in Lepr−/− rats. Moreover, LWE remarkably reduced hepatic lipid accumulation and alleviated fatty liver formation in Lepr−/− rats. A mechanistic study showed that LWE obviously activated SIRT6 and decreased the expression of key lipogenesis-related molecules SREBP1, FAS, and DGAT1 in the livers of Lepr−/− rats. Furthermore, LWE significantly improved microbiota dysbiosis via an increase in gut microbiota diversity and an abundance of the microbiota that produce short chain fatty acids (SCFAs), such as Ruminococcaceae, Faecalibaculum, Intestinimonas, and Alistipes. Finally, LWE supplementation increased the concentrations of SCFAs in the feces of Lepr−/− rats. These results revealed that LWE attenuated metabolic syndrome of Lepr−/− rats via the reduction of hepatic lipid synthesis through the SIRT6/SREBP1 pathway and the modulation of gut microbiota.

Fecal Microbiome Differences in Angus Steers with Differing Feed Efficiencies during the Feedlot-Finishing Phase

The gastrointestinal microbiota of cattle is important for feedstuff degradation and feed efficiency determination. This study evaluated the fecal microbiome of Angus steers with distinct feed efficiencies during the feedlot-finishing phase. Angus steers (n = 65), fed a feedlot-finishing diet for 82 days, had growth performance metrics evaluated. Steers were ranked based upon residual feed intake (RFI), and the 5 lowest RFI (most efficient) and 5 highest RFI (least efficient) steers were selected for evaluation. Fecal samples were collected on 0-d and 82-d of the finishing period and microbial DNA was extracted and evaluated by 16S rRNA gene sequencing. During the feedlot trial, inefficient steers had decreased (p = 0.02) Ruminococcaceae populations and increased (p = 0.01) Clostridiaceae populations. Conversely, efficient steers had increased Peptostreptococcaceae (p = 0.03) and Turicibacteraceae (p = 0.01), and a trend for decreased Proteobacteria abundance (p = 0.096). Efficient steers had increased microbial richness and diversity during the feedlot period, which likely resulted in increased fiber-degrading enzymes in their hindgut, allowing them to extract more energy from the feed. Results suggest that cattle with better feed efficiency have greater diversity of hindgut microorganisms, resulting in more enzymes available for digestion, and improving energy harvest in the gut of efficient cattle.

Dietary Aronia melanocarpa Pomace Supplementation Enhances the Expression of ZO-1 and Occludin and Promotes Intestinal Development in Pigs

A fruit juice production byproduct, Aronia melanocarpa pomace (AMP) is rich in natural polyphenol antioxidant components. The objectives of this study were to study the effects of dietary AMP supplementation on the feeding outcome and intestinal barrier function of pigs. In total, 27 growing pigs (Duroc × Landrace × Yorkshire, ~60 days, average weight of 27.77 ± 2.87 kg, males and females included at random) were randomly allotted to 3 treatment groups, with 3 repetitions per group and 3 pigs per repetition. At the experiment completion, 2 pigs (close to the average body weight of all experimental pigs) per replicate were slaughtered. The control group (CON group) was fed a basic diet, and the experimental groups were fed 4% (4% AMP group) and 8% (8% AMP group) AMP in the basic diet. These pigs were prefed for 3 days, and the formal experiments were performed for 7 weeks. The results showed that compared with the CON diet, the 4% AMP supplementation significantly increased the average daily gain of pigs (P < 0.05). Regarding intestinal development, 4% AMP significantly increased the jejunal villus height/crypt depth ratio (P < 0.05), and different AMP levels had no significant effect on the pig cecum morphology. Different AMP levels significantly decreased the relative abundance of Proteobacteria (P < 0.05). Regarding other microbial genera, 4% AMP supplementation significantly increased the levels of Lachnospira, Solobacterium, Romboutsia and other beneficial microorganisms (P < 0.05). Different AMP levels significantly decreased the relative abundances of the opportunistic pathogens Escherichia-Shigella and Pseudoscardovia (P < 0.05) and increased the contents of acetic acid and butyric acid in the pig cecal contents (P < 0.05). Compared with the CON treatment, 4% AMP supplementation significantly downregulated the jejunal gene expression of porcine proinflammatory factors (IL-1β, IL-6, IL-8 and TNF-α) and significantly upregulated the jejunal gene expression of ZO-1, Occludin and Claudin-1 (P < 0.05). In conclusion, 4% AMP supplementation in feed is beneficial to overall pig health and growth.

Gut microbiota predicts body fat change following a low-energy diet: a PREVIEW intervention study

Background

Low-energy diets (LEDs) comprise commercially formulated food products that provide between 800 and 1200 kcal/day (3.3–5 MJ/day) to aid body weight loss. Recent small-scale studies suggest that LEDs are associated with marked changes in the gut microbiota that may modify the effect of the LED on host metabolism and weight loss. We investigated how the gut microbiota changed during 8 weeks of total meal replacement LED and determined their associations with host response in a sub-analysis of 211 overweight adults with pre-diabetes participating in the large multicentre PREVIEW (PREVention of diabetes through lifestyle intervention and population studies In Europe and around the World) clinical trial.

Methods

Microbial community composition was analysed by Illumina sequencing of the hypervariable V3-V4 regions of the 16S ribosomal RNA (rRNA) gene. Butyrate production capacity was estimated by qPCR targeting the butyryl-CoA:acetate CoA-transferase gene. Bioinformatics and statistical analyses, such as comparison of alpha and beta diversity measures, correlative and differential abundances analysis, were undertaken on the 16S rRNA gene sequences of 211 paired (pre- and post-LED) samples as well as their integration with the clinical, biomedical and dietary datasets for predictive modelling.

Results

The overall composition of the gut microbiota changed markedly and consistently from pre- to post-LED (P = 0.001), along with increased richness and diversity (both P < 0.001). Following the intervention, the relative abundance of several genera previously associated with metabolic improvements (e.g., Akkermansia and Christensenellaceae R-7 group) was significantly increased (P < 0.001), while flagellated Pseudobutyrivibrio, acetogenic Blautia and Bifidobacterium spp. were decreased (all P < 0.001). Butyrate production capacity was reduced (P < 0.001). The changes in microbiota composition and predicted functions were significantly associated with body weight loss (P < 0.05). Baseline gut microbiota features were able to explain ~25% of variation in total body fat change (post–pre-LED).

Conclusions

The gut microbiota and individual taxa were significantly influenced by the LED intervention and correlated with changes in total body fat and body weight in individuals with overweight and pre-diabetes. Despite inter-individual variation, the baseline gut microbiota was a strong predictor of total body fat change during the energy restriction period.

Trial registration

The PREVIEW trial was prospectively registered at ClinicalTrials.gov (NCT01777893) on January 29, 2013.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-022-01053-7.