The Specific Roles of Vitamins in the Regulation of Immunosurveillance and Maintenance of Immunologic Homeostasis in the Gut

Predictive value of three nutritional indexes for disease activity in patients with inflammatory bowel disease

BACKGROUND

Malnutrition is prevalent in patients with inflammatory bowel disease (IBD); however, its ability to predict the disease activity in IBD remains unexplored. Therefore, this study aimed to explore the association between malnutrition and disease activity in IBD.

METHODS

In this retrospective study, we enrolled 1006 patients diagnosed with IBD from the First Affiliated Hospital of Wenzhou Medical University from 2011 to 2022. Malnutrition was assessed based on the prognostic nutritional index (PNI), geriatric nutritional risk index (GNRI), and controlling nutritional status (CONUT) scores. Logistic regression analyses were performed to identify predictors for disease activity. Restricted cubic spline analysis was performed to evaluate the possible nonlinear relations, and subgroup analysis was performed to explore potential interactions. Additionally, prediction performances were compared through receiver operating characteristic curves, net reclassification improvement, and integrated discrimination improvement.

RESULTS

The prevalence of malnutrition calculated by the PNI, GNRI, and CONUT scores in IBD was 16.9%, 72.1%, and 75.6%, respectively and significant correlations were observed among them. Multivariate logistic regression analysis showed that PNI, GNRI, and CONUT were independent risk factors for disease activity, and no significant nonlinear relationship was observed between disease activity and all three indexes. No statistically significant interactive effect was found in nearly all the subgroups. GNRI showed the highest predictive value compared with PNI and CONUT. Additionally, combining any of the three indexes improved the ability of C-reactive protein to predict IBD activity.

CONCLUSIONS

All three nutritional indexes evaluated malnutrition to be an independent risk factor for IBD activity.

Identification of disease-specific gut microbial markers in vitiligo

There is a potential correlation between vitiligo and gut microbiota, although research in this area is currently limited. The research employed high-throughput sequencing of 16S rRNA to examine the gut microbiome in the stool samples of 49 individuals with vitiligo and 49 without the condition. The study encompassed four comparison groups: (1) DI (disease) group vs. HC (healthy control) group; (2) DI_m group (disease group of minors) vs. HC_m group (healthy control group of minors); (3) DI_a group (adult disease group) vs. HC_a group (adult healthy control group); (4) DI_m group vs. DI_a group. Research findings have indicated the presence of spatial heterogeneity in the gut microbiota composition between individuals with vitiligo and healthy controls. A significant reduction in gut microbiota diversity has been observed in vitiligo patients across both minors and adult groups. However, variations have been noted in the composition of disease-related differential microbial markers among different age groups. Specifically, Bacteroides and Parabacteroides have been identified as specific markers of the intestinal microbiota of vitiligo patients in both minor and adult groups. Correlative analyses have revealed a positive correlation of these two genera with the Vitiligo Area Scoring Index (VASI) and disease duration. It is noteworthy that there are no significant differences in diversity between the DI_m group and the DI_a group, with similarities in microbiota composition and functional characteristics. Nevertheless, correlative analyses suggest a declining trend in Bacteroides and Parabacteroides with increasing age. Individuals with vitiligo exhibit distinct features in their gut microbiome when contrasted with those in the healthy control group. Additionally, the microbial marker genera that show variances between patients and healthy controls vary among different age groups. Disease-specific microbial marker genera (Bacteroides and Parabacteroides) are associated with VASI, duration of the condition, and age. These findings are essential for improving early diagnosis and developing potential treatment strategies for individuals with vitiligo.

The injection of maternal B complex vitamin during the transition period: The impact on performance, thyroid hormones levels and immunological parameters in the Sannen goats and their kids, as well as the faeces status of newborn kids

BACKGROUND

It is proven that B vitamins through promote a wide range of metabolic pathways in animals as cofactors improve animal performance.

OBJECTIVES

This study was conducted to investigate the impacts of maternal B complex vitamin injection on performance and plasma parameters in goats and their offspring, as well as the faeces status of newborn kids.

METHODS

In this research, the pregnant goats (3 years old) were randomly divided into two groups: the control group (without B complex vitamin injection) and the B complex vitamin group (5 mL B complex vitamin injection per animal). The animals were injected with 5 mL B complex vitamin twice during the transition period (5 weeks pre- and 5 weeks post-kidding). The goats during the transition period and kids on days 10, 20 and 30 were weighed. Feed intake by goats and consumption of milk and starter in kids were recorded daily. The dry matter digestibility by kids was tested by collecting samples of faeces and feed for 5 days in the last week. Chemical analysis was determined using the AOAC method. The kids' faeces were prepared daily during the study. The blood samples of goats and newborn kids were taken 7 days after kidding. Then, levels of B group vitamin, as well as concentrations of liver enzymes, thyroid hormones and immunological parameters, were determined in plasma of goat and their offspring. In addition, concentrations of glucose and insulin were measured in goat plasma (Asadi et al., 2024).

RESULTS

According to results, the performances of goats and their offspring, as well as kids' faeces status, were improved by maternal B complex vitamin injection (p < 0.0001). The levels of cobalamin, pyridoxine, thiamine, folic acid, nicotinic, pantothenic and unconjugated pteridine increased in the plasma of goats and their kids in the B complex vitamin group compared with the control group during the transition period (p < 0.0001). Injection of maternal B complex vitamin raised the plasma levels of triiodothyronine and tetraiodothyronine, immunoglobulin G and immunoglobulin M in goats and their offspring (p < 0.0001). Higher levels of glucose and lower levels of insulin were determined in the goats injected with B complex vitamin (p < 0.0001).

CONCLUSIONS

These results suggest that maternal B complex vitamin injection is required for the improvement of performance, health status and the blood plasma parameters in pregnant goats and their kids.

Correlation between fat-soluble vitamin levels and inflammatory factors in paediatric community-acquired pneumonia: A prospective study

Community-acquired pneumonia (CAP) is a common respiratory disease in children. This prospective cohort study of 110 children with CAP and 100 healthy children investigated the relationship between the levels of vitamin A, D and E and inflammatory markers, such as tumour necrosis factor (TNF-a), interleukin-1 (IL-1), interleukin-10 (IL-10), neutrophils (NE) and C-reactive protein (CRP), in CAP. The haemoglobin, leukocyte concentration, NE, monocytes and CRP concentration in the CAP group showed significant differences (P < 0.05). The levels of vitamin A, D and E in the CAP group were lower than those in the control group, while the levels of TNF-a and IL-1 were higher than in the control group; the differences were statistically significant (P < 0.05). The IL-10 levels showed no significant differences (P > 0.05). Pearson analysis revealed that the vitamin A, D and E levels were all correlated with the TNF-a, IL-10 and CRP levels (P < 0.05). The vitamin A, D and E levels of the CAP children were lower than those of the healthy children. Thus, the content of fat-soluble vitamins is correlated with the secretion of TNF-a and IL-10. The research provides a new direction for the prevention, diagnosis and treatment of CAP.

Inflammation and malnutrition in inflammatory bowel disease

Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, has become increasingly prevalent worldwide in the past decade. The nutritional status of patients with IBD is often impaired, with malnutrition presenting as imbalanced energy or nutrient intake, including protein-energy malnutrition, disease-related malnutrition, sarcopenia, and micronutrient deficiency. Additionally, malnutrition can manifest as overweight, obesity, and sarcopenic obesity. Malnutrition can lead to disturbances in gut microbiome composition that might alter homoeostasis and cause a dysbiotic state, potentially triggering inflammatory responses. Despite the clear link between IBD and malnutrition, little is known about the pathophysiological mechanisms beyond protein-energy malnutrition and micronutrient deficiencies that could promote inflammation through malnutrition, and vice versa. This Review focuses on potential mechanisms that trigger a vicious cycle between malnutrition and inflammation, and their clinical and therapeutic implications.

A Scoping Review of Vitamin D for Nonskeletal Health: A Framework for Evidence-based Clinical Practice

BACKGROUND

Low serum 25-hydroxy-vitamin D [25(OH)D] levels are prevalent worldwide. Although the benefits of vitamin D supplementation have focused on skeletal disorders (eg, rickets, osteomalacia, osteoporosis), emerging evidence for nonskeletal health merits further discussion.

PURPOSE

The purpose of this review was to critically examine the vitamin D supplementation literature pertaining to nonskeletal health to help guide clinicians.

METHODS

A scoping review that included observational studies and randomized clinical trials (RCTs) was performed. Evidence from meta-analyses and individual RCTs are discussed, and controversies and future directions are considered.

FINDINGS

25(OH)D deficiency is a ubiquitous condition associated with multiple nonskeletal diseases, including cardiometabolic (heart disease, diabetes, and kidney disease), immune (HIV/AIDS and cancer), lung (from traditional chronic disorders to coronavirus disease 2019), and gut diseases. Vitamin D deficiency also affects health across the life span (children, pregnant, and elderly), mental illness, and reproduction in both men and women. In contrast, vitamin D supplementation does not necessarily improve major medical outcomes, even when low 25(OH)D levels are treated. Screening for 25(OH)D status remains an important practice, primarily for high-risk patients (eg, elderly, women with osteoporosis, people with low exposure to sunlight). It is reasonable to supplement with vitamin D to treat 25(OH)D deficiency, such that if beneficial nonskeletal health occurs, this may be considered as a coadjutant instead of the central tenet of the disease. Furthermore, optimizing dosing regimens is an important clinical consideration.

IMPLICATIONS

Although 25(OH)D deficiency is prevalent in nonskeletal diseases, there is no uniform evidence that vitamin D supplementation improves major medical outcomes, even when low 25(OH)D levels are corrected. Findings from RCTs warrant caution due to possible selection bias. Overall, vitamin D supplementation must be guided by circulating levels as a reasonable medical practice to correct 25(OH)D deficiency.

In Vivo Acute Toxicity and Immunomodulation Assessment of a Novel Nutraceutical in Mice

Achieving and maintaining a well-balanced immune system has righteously become an insightful task for the general population and an even more fundamental goal for those affected by immune-related diseases. Since our immune functions are indispensable in defending the body against pathogens, diseases and other external attacks, while playing a vital role in maintaining health and modulating the immune response, we require an on-point grasp of their shortcoming as a foundation for the development of functional foods and novel nutraceuticals. Seeing that immunoceuticals are considered effective in improving immune functions and reducing the incidence of immunological disorders, the main focus of this study was to assess the immunomodulatory properties and possible acute toxicity of a novel nutraceutical with active substances of natural origin on C57BL/6 mice for 21 days. We evaluated the potential hazards (microbial contamination and heavy metals) of the novel nutraceutical and addressed the acute toxicity according to OECD guidelines of a 2000 mg/kg dose on mice for 21 days. The immunomodulatory effect was assessed at three concentrations (50 mg/kg, 100 mg/kg and 200 mg/kg) by determining body and organ indexes through a leukocyte analysis; flow cytometry immunophenotyping of lymphocytes populations and their subpopulations (T lymphocytes (LyCD3+), cytotoxic suppressor T lymphocytes (CD3+CD8+), helper T lymphocytes (CD3+CD4+), B lymphocytes (CD3-CD19+) and NK cells (CD3-NK1.1.+); and the expression of the CD69 activation marker. The results obtained for the novel nutraceutical referred to as ImunoBoost indicated no acute toxicity, an increased number of lymphocytes and the stimulation of lymphocyte activation and proliferation, demonstrating its immunomodulatory effect. The safe human consumption dose was established at 30 mg/day.

Metabolite interactions between host and microbiota during health and disease: Which feeds the other?

Metabolites produced by the host and microbiota play a crucial role in how human bodies develop and remain healthy. Most of these metabolites are produced by microbiota and hosts in the digestive tract. Metabolites in the gut have important roles in energy metabolism, cellular communication, and host immunity, among other physiological activities. Although numerous host metabolites, such as free fatty acids, amino acids, and vitamins, are found in the intestine, metabolites generated by gut microbiota are equally vital for intestinal homeostasis. Furthermore, microbiota in the gut is the sole source of some metabolites, including short-chain fatty acids (SCFAs). Metabolites produced by microbiota, such as neurotransmitters and hormones, may modulate and significantly affect host metabolism. The gut microbiota is becoming recognized as a second endocrine system. A variety of chronic inflammatory disorders have been linked to aberrant host-microbiota interplays, but the precise mechanisms underpinning these disturbances and how they might lead to diseases remain to be fully elucidated. Microbiome-modulated metabolites are promising targets for new drug discovery due to their endocrine function in various complex disorders. In humans, metabolotherapy for the prevention or treatment of various disorders will be possible if we better understand the metabolic preferences of bacteria and the host in specific tissues and organs. Better disease treatments may be possible with the help of novel complementary therapies that target host or bacterial metabolism. The metabolites, their physiological consequences, and functional mechanisms of the host-microbiota interplays will be highlighted, summarized, and discussed in this overview.

Protective Effect of Anthocyanins against Neurodegenerative Diseases through the Microbial-Intestinal-Brain Axis: A Critical Review

With the increase in human mean age, the prevalence of neurodegenerative diseases (NDs) also rises. This negatively affects mental and physiological health. In recent years, evidence has revealed that anthocyanins could regulate the functioning of the central nervous system (CNS) through the microbiome-gut-brain axis, which provides a new perspective for treating NDs. In this review, the protective effects and mechanisms of anthocyanins against NDs are summarized, especially the interaction between anthocyanins and the intestinal microbiota, and the microbial-intestinal-brain axis system is comprehensively discussed. Moreover, anthocyanins achieve the therapeutic purpose of NDs by regulating intestinal microflora and certain metabolites (protocateic acid, vanillic acid, etc.). In particular, the inhibitory effect of tryptophan metabolism on some neurotransmitters and the induction of blood-brain barrier permeability by butyrate production has a preventive effect on NDs. Overall, it is suggested that microbial-intestinal-brain axis may be a novel mechanism for the protective effect of anthocyanins against NDs.

Encapsulation of Vitamins Using Nanoliposome: Recent Advances and Perspectives

Nowadays the importance of vitamins is clear for everyone. However, many patients are suffering from insufficient intake of vitamins. Incomplete intake of different vitamins from food sources due to their destruction during food processing or decrease in their bioavailability when mixing with other food materials, are factors resulting in vitamin deficiency in the body. Therefore, various lipid based nanocarriers such as nanoliposomes were developed to increase the bioavailability of bioactive compounds. Since the function of nanoliposomes containing vitamins on the body has a direct relationship with the quality of produced nanoliposomes, this review study was planned to investigate the several aspects of liposomal characteristics such as size, polydispersity index, zeta potential, and encapsulation efficiency on the quality of synthesized vitamin-loaded nanoliposomes.

Advances in understanding of effects of dietary nutrients in inflammatory bowel disease patients

The occurrence of inflammatory bowel disease (IBD) is influenced by environmental factors. Diet, as an important environmental factor, is closely associated with intestinal ecology and plays a critical role in the pathological process of IBD. This review summarizes the role of major dietary nutrients in the pathogenesis of IBD, with an aim to provide clues for the prevention and treatment of IBD.

Role of Postbiotics in Diet-Induced Metabolic Disorders

Although the prevalence of metabolic disorders has progressively increased over the past few decades, metabolic disorders can only be effectively treated with calorie restriction and improved physical activity. Recent research has focused on altering the gut microbiome using prebiotics, probiotics, and postbiotics because various metabolic syndromes are caused by gut microbial dysbiosis. Postbiotics, substances produced or released by microorganism metabolic activities, play an important role in maintaining and restoring host health. Because postbiotics have a small amount of literature on their consumption, there is a need for more experiments on short- and long-term intake. This review discusses current postbiotic research, categories of postbiotics, positive roles in metabolic syndromes, and potential therapeutic applications. It covers postbiotic pleiotropic benefits, such as anti-obesity, anti-diabetic, and anti-hypertensive qualities, that could aid in the management of metabolic disorders. Postbiotics are promising tools for developing health benefits and therapeutic goals owing to their clinical, technical, and economic properties. Postbiotic use is attractive for altering the microbiota; however, further studies are needed to determine efficacy and safety.

Crohn's Disease and Female Infertility: Can Nutrition Play a Supporting Role?

Crohn's disease (CD) is a chronic inflammatory disease (IBD) that can affect the entire gastrointestinal tract in a non-continuous mode. CD is generally diagnosed most commonly between 15 and 35 years of age and may affect female fertility. The role of diet in supporting wellbeing outcome and reproductive potential in women is well-known; however, no effective efforts have been made to improve women's awareness in CD. Our review aims to describe the burden of CD on women's fertility, reporting the most relevant nutrients that support reproductive function to ensure women diagnosed with IBD an adequate health-related quality of life.

The Role of Mineral Deficiencies in Insulin Resistance and Obesity

Minerals are critical for maintaining overall health. These tiny chemical compounds are responsible for enzymatic activation, maintaining healthy teeth and bones, regulating energy metabolism, enhancing immunity, and aiding muscle and brain function. However, mineral deficiency in the form of inadequate or under nourished intake affects millions of people throughout the world, with well-documented adverse health consequences of malnutrition. Conversely, mineral deficiency may also be a risk factor for Insulin Resistance (IR) and obesity. This review focuses on another, more "less discussed" form of malnutrition, namely mineral deficiency and its contribution to metabolic disorders. At the cellular level, minerals maintain not only molecular communication but also trigger several key biochemical pathways. Disturbances in these processes due to mineral insufficiency may gradually lead to metabolic disorders such as insulin resistance, pre-diabetes, and central obesity, which might lead to renal failure, cardiac arrest, hepatic carcinoma, and various neurodegenerative diseases. Here we discuss the burden of disease promoted by mineral deficiencies and the medical, social, and economic consequences. Mineral deficiency-mediated IR and obesity have a considerable negative impact on individual well-being, physical consideration, and economic productivity. We discuss possible molecular mechanisms of mineral deficiency that may lead to IR and obesity and suggest strategies to counter these metabolic disorders. To protect mankind from mineral nutrient deficiencies, the key is to take a variety of foods in reasonable quantities, such as organic and pasture-raised eggs, low fat dairy, and grass-fed and finished meats, insecticide, and pesticide-free vegetables and fruits.

Influence of Probiotic Supplementation on Health Status of the Dogs: A Review

Most commonly, pet dogs suffer from gastrointestinal (GI) diseases due to careless eating behaviors, such as eating food other than dog food; excess or insufficient nutrient intake of food leading to malnutrition, which could be harmful to dogs; a lack of digestive enzymes; food intolerance or allergies; infections; and/or breed-related hypersensitivities. Probiotics are live microorganisms that deliver health benefits to the host when administrated in an adequate amount. The possible mechanism behind probiotics’ beneficial effects could be their positive regulation of the host’s intestinal microbiota. Probiotics are reported to have therapeutic properties against canine GI and other diseases. The most suitable dosages and applications of probiotics have not been evaluated extensively. The present review summarizes current knowledge regarding the benefits of probiotics and the changes in canine microbiota during probiotic interventions. This literature review provides clinical evidence for probiotics’ beneficial effects in preventing or treating canine ill-health conditions. Based on current knowledge, subsequent researchers could develop or improve probiotics-based canine pharmacological products.

Extracellular vesicles derived from gut microbiota in inflammatory bowel disease and colorectal cancer: new players?

The human gut microbiome encompasses inter alia, the myriad bacterial species that create the optimal host-microorganism balance essential for normal metabolic and immune function. Various lines of evidence suggest that dysregulation of the microbiota-host interaction is linked to pathologies such as inflammatory bowel disease (IBD) and colorectal cancer (CRC). Extracellular vesicles (EVs), found in virtually all body fluids and produced by both eukaryotic cells and bacteria are involved in cell-cell communication and crosstalk mechanisms, such as the immune response, barrier function and intestinal flora. This review highlights advancements in knowledge of the functional role that EVs may have in IBD and CRC, and discusses the possible use of EVs derived from intestinal microbiota in therapeutic strategies for treating these conditions.

Spices, Condiments, Extra Virgin Olive Oil and Aromas as Not Only Flavorings, but Precious Allies for Our Wellbeing

Spices, condiments and extra virgin olive oil (EVOO) are crucial components of human history and nutrition. They are substances added to foods to improve flavor and taste. Many of them are used not only to flavor foods, but also in traditional medicine and cosmetics. They have antioxidant, antiviral, antibiotic, anticoagulant and antiinflammatory properties and exciting potential for preventing chronic degenerative diseases such as cardiomyopathy and cancer when used in the daily diet. Research and development in this particular field are deeply rooted as the consumer inclination towards natural products is significant. It is essential to let consumers know the beneficial effects of the daily consumption of spices, condiments and extra virgin olive oil so that they can choose them based on effects proven by scientific works and not by the mere illusion that plant products are suitable only because they are natural and not chemicals. The study begins with the definition of spices, condiments and extra virgin olive oil. It continues by describing the pathologies that can be prevented with a spicy diet and it concludes by considering the molecules responsible for the beneficial effects on human health (phytochemical) and their eventual transformation when cooked.

Predictive Metagenomic Analysis of Autoimmune Disease Identifies Robust Autoimmunity and Disease Specific Microbial Signatures

Within the last decade, numerous studies have demonstrated changes in the gut microbiome associated with specific autoimmune diseases. Due to differences in study design, data quality control, analysis and statistical methods, many results of these studies are inconsistent and incomparable. To better understand the relationship between the intestinal microbiome and autoimmunity, we have completed a comprehensive re-analysis of 42 studies focusing on the gut microbiome in 12 autoimmune diseases to identify a microbial signature predictive of multiple sclerosis (MS), inflammatory bowel disease (IBD), rheumatoid arthritis (RA) and general autoimmune disease using both 16S rRNA sequencing data and shotgun metagenomics data. To do this, we used four machine learning algorithms, random forest, eXtreme Gradient Boosting (XGBoost), ridge regression, and support vector machine with radial kernel and recursive feature elimination to rank disease predictive taxa comparing disease vs. healthy participants and pairwise comparisons of each disease. Comparing the performance of these models, we found the two tree-based methods, XGBoost and random forest, most capable of handling sparse multidimensional data, to consistently produce the best results. Through this modeling, we identified a number of taxa consistently identified as dysregulated in a general autoimmune disease model including Odoribacter, Lachnospiraceae Clostridium, and Mogibacteriaceae implicating all as potential factors connecting the gut microbiome to autoimmune response. Further, we computed pairwise comparison models to identify disease specific taxa signatures highlighting a role for Peptostreptococcaceae and Ruminococcaceae Gemmiger in IBD and Akkermansia, Butyricicoccus, and Mogibacteriaceae in MS. We then connected a subset of these taxa with potential metabolic alterations based on metagenomic/metabolomic correlation analysis, identifying 215 metabolites associated with autoimmunity-predictive taxa.

Metabolic reprogramming of T regulatory cells in the hypoxic tumor microenvironment

Metabolic dysregulation in the hypoxic tumor microenvironment (TME) is considered as a hallmark of solid tumors, leading to changes in biosynthetic pathways favoring onset, survival and proliferation of malignant cells. Within the TME, hypoxic milieu favors metabolic reprogramming of tumor cells, which subsequently affects biological properties of tumor-infiltrating immune cells. T regulatory cells (Tregs), including both circulating and tissue-resident cells, are particularly susceptible to hypoxic metabolic signaling that can reprogram their biological and physicochemical properties. Furthermore, metabolic reprogramming modifies Tregs to utilize alternative substrates and undergo a plethora of metabolic events to meet their energy demands. Major impact of this metabolic reprogramming can result in differentiation, survival, excessive secretion of immunosuppressive cytokines and proliferation of Tregs within the TME, which in turn dampen anti-tumor immune responses. Studies on fine-tuning of Treg metabolism are challenging due to heterogenicity of tissue-resident Tregs and their dynamic functions. In this review, we highlight tumor intrinsic and extrinsic factors, which can influence Treg metabolism in the hypoxic TME. Moreover, we focus on metabolic reprogramming of Tregs that could unveil potential regulatory networks favoring tumorigenesis/progression, and provide novel insights, including inhibitors against acetyl-coA carboxylase 1 and transforming growth factor beta into targeting Treg metabolism for therapeutic benefits.

Diversity of energy metabolism in immune responses regulated by micro-organisms and dietary nutrition

Immune metabolism has been recognized as a new paradigm in the regulation of host immunity. In the environment, there are many micro-organisms including pathogenic and non-pathogenic and/or beneficial ones. Immune cells exhibit various responses against different types of microbes, which seem to be associated with changes in energy metabolism. In addition, dietary nutrition influences host metabolism and consequent responses by immune cells. In this review, we describe the complex network of immune metabolism from the perspectives of nutrition, micro-organisms and host immunity for the control of immunologic health and diseases.

Gut Biofactory-Neurocompetent Metabolites within the Gastrointestinal Tract. A Scoping Review

The gut microbiota have gained much scientific attention recently. Apart from unravelling the taxonomic data, we should understand how the altered microbiota structure corresponds to functions of this complex ecosystem. The metabolites of intestinal microorganisms, especially bacteria, exert pleiotropic effects on the human organism and contribute to the host systemic balance. These molecules play key roles in regulating immune and metabolic processes. A subset of them affect the gut brain axis signaling and balance the mental wellbeing. Neurotransmitters, short chain fatty acids, tryptophan catabolites, bile acids and phosphatidylcholine, choline, serotonin, and L-carnitine metabolites possess high neuroactive potential. A scoping literature search in PubMed/Embase was conducted up until 20 June 2020, using three major search terms "microbiota metabolites" AND "gut brain axis" AND "mental health". This review aimed to enhance our knowledge regarding the gut microbiota functional capacity, and support current and future attempts to create new compounds for future clinical interventions.

Impact of the intestinal environment on the immune responses to vaccination

Vaccination has contributed greatly to the control of infectious diseases; however, regional and individual differences are occasionally observed in the efficacy of vaccination. As one explanation for these differences, much attention has focused on the intestinal environment constructed by the interaction of diet and the gut microbiota. The intestinal environment has several physiological effects on the host immune system, both locally and systemically, and consequently influences the efficacy of vaccination. In this review, we discuss the impact of the gut microbiota and dietary nutrients on systemic and oral vaccination as well as their applications in various strategies for immunoregulation, including use as vaccine adjuvants. This information could contribute to establishing methods of personalized vaccination that would optimize host immunity by changing the gut environment to maximize vaccine effects.

Fatty acid metabolism in the host and commensal bacteria for the control of intestinal immune responses and diseases

Intestinal tissue has a specialized immune system that exhibits an exquisite balance between active and suppressive responses important for the maintenance of health. Intestinal immunity is functionally affected by both diet and gut commensal bacteria. Here, we review the effects of fatty acids on the regulation of intestinal immunity and immunological diseases, revealing that dietary fatty acids and their metabolites play an important role in the regulation of allergy, inflammation, and immunosurveillance in the intestine. Several lines of evidence have revealed that some dietary fatty acids are converted to biologically active metabolites by enzymes not only in the host but also in the commensal bacteria. Thus, biological interaction between diet and commensal bacteria could form the basis of a new era in the control of host immunity and its associated diseases.

Micronutrient Absorption and Related Outcomes in People with Inflammatory Bowel Disease: A Review

Inflammatory Bowel Disease (IBD) is a chronic disorder associated with immune dysregulation and chronic inflammation of the digestive tract. While it is poorly understood, the role of nutrition and nutrient status in the etiology of IBD and its associated outcomes has led to increased research relating to micronutrient deficiency. This review offers an overview of recent literature related to micronutrient absorption and outcomes in adults with IBD. Although the absorption and IBD-related outcomes of some micronutrients (e.g., vitamin D and iron) are well understood, other micronutrients (e.g., vitamin A) require further research. Increased research and clinician knowledge of the relationship between micronutrients and IBD may manifest in improved nutrient screening, monitoring, treatment, and outcomes for people living with IBD.

The prominent alteration in transcriptome and metabolome of Mycobacterium bovis BCG str. Tokyo 172 induced by vitamin B1

BACKGROUND

Vitamin B1 (VB1) is a crucial dietary nutrient and essential cofactor for several key enzymes in the regulation of cellular and metabolic processes, and more importantly in the activation of immune system. To date, the precise role of VB1 in Mycobacterium tuberculosis remains to be fully understood.

RESULTS

In this study, the transcriptional and metabolic profiles of VB1-treated Mycobacterium. bovis BCG were analyzed by RNA-sequencing and LC-MS (Liquid chromatography coupled to mass spectrometry). The selection of BCG strain was based on its common physiological features shared with M. tuberculosis. The results of cell growth assays demonstrated that VB1 inhibited the BCG growth rate in vitro. Transcriptomic analysis revealed that the expression levels of genes related to fatty acid metabolism, cholesterol metabolism, glycolipid catabolism, DNA replication, protein translation, cell division and cell wall formation were significantly downregulated in M. bovis BCG treated with VB1. In addition, the metabolomics LC-MS data indicated that most of the amino acids and adenosine diphosphate (ADP) were decreased in M. bovis BCG strain after VB1 treatment.

CONCLUSIONS

This study provides the molecular and metabolic bases to understand the impacts of VB1 on M.bovis BCG.

Metabolism of Dietary and Microbial Vitamin B Family in the Regulation of Host Immunity

Vitamins are micronutrients that have physiological effects on various biological responses, including host immunity. Therefore, vitamin deficiency leads to increased risk of developing infectious, allergic, and inflammatory diseases. Since B vitamins are synthesized by plants, yeasts, and bacteria, but not by mammals, mammals must acquire B vitamins from dietary or microbial sources, such as the intestinal microbiota. Similarly, some intestinal bacteria are unable to synthesize B vitamins and must acquire them from the host diet or from other intestinal bacteria for their growth and survival. This suggests that the composition and function of the intestinal microbiota may affect host B vitamin usage and, by extension, host immunity. Here, we review the immunological functions of B vitamins and their metabolism by intestinal bacteria with respect to the control of host immunity.

Dietary and Microbial Metabolites in the Regulation of Host Immunity

Mucosal surfaces in the body, especially the intestine, are constantly exposed to trillions of microbiomes. Accumulating evidence has revealed that changes in the composition of the gut microbiome, especially that of the commensal bacteria population, are frequently associated with immunologic disorders. These changes coincide with changes in the production of certain dietary metabolites. Recent studies have uncovered the molecular and cellular mechanisms underlying the relationships among diet, commensal bacteria, and the host immune system. In this review, we describe how dietary and microbial metabolites modulate host immunity.