Clustering according to urolithin metabotype explains the interindividual variability in the improvement of cardiovascular risk biomarkers in overweight-obese individuals consuming pomegranate: A randomized clinical trial

An updated systematic review and meta-analysis of pomegranate consumption on lipid profile

Pomegranate, rich in bioactive compounds such as polyphenols and flavonoids, has been studied for its potential lipid-modulating effects, yet evidence remains inconsistent. This systematic review and meta-analysis aimed to evaluate the impact of pomegranate consumption on plasma lipid profiles by synthesizing data from randomized controlled trials (RCTs). Following PRISMA guidelines, 37 RCTs (n = 2695 participants) were included after searching Scopus and MEDLINE databases. Studies assessed pomegranate products (juice, extract, seed oil) administered orally for ≥ 7 days, with lipid parameters, including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG) as outcomes. Data were pooled using RevMan 5.3 with random-effects models. Results indicated that pomegranate intake significantly increased HDL-C levels (mean difference: 2.50 mg/dL, 95 % CI: 1.00-4.00, p < 0.05), while no significant changes were observed in TC, LDL-C, or TG. Subgroup analyses revealed pronounced HDL-C elevation in non-alcoholic fatty liver disease (NAFLD) patients, health participants and interventions lasting ≥ 8 weeks. Heterogeneity across studies was attributed to variations in intervention duration, dosage forms, and participant characteristics. Publication bias was nonsignificant (Egger's test, p > 0.05). These findings suggest that pomegranate supplementation may improve HDL-C, potentially through modulation of HDL-associated enzymes like paraoxonase. However, further large-scale, long-term RCTs are warranted to confirm these effects and explore synergistic benefits with standard lipid-lowering therapies.

Assessing quality and polyphenol in vitro bioaccessibility in healthy jelly gummies with microencapsulated and non-encapsulated pomegranate peel extract

BACKGROUND

Pomegranate peel extract (PPE) is rich in polyphenols, notably punicalagin and ellagic acid, but is sensitive to environmental degradation and has low bioavailability. Microencapsulation can enhance PPE stability and bioaccessibility, making it suitable for functional foods like jelly gummies (JG). JG containing microencapsulated PPE (MPPE) have not been studied.

OBJECTIVE

To characterize a JG prototype incorporating PPE or MPPE and compare the bioaccessibility of total polyphenols (TP), punicalagin, and ellagic acid after a simulated in vitro digestion.

METHODS

PPE-JG and MPPE-JG prototypes were evaluated for physical, sensory, and chemical properties. The bioaccessibility of the main bioactive compounds was analyzed using the INFOGEST digestion protocol.

RESULTS

Bioaccessibility was significantly higher for MPPE-JG compared to PPE-JG for TP (164.1 ± 6.0 vs. 100.0 ± 5.8 %, respectively) and punicalagin (173.4 ± 4.4 vs. 106.5 ± 4.2 %, respectively). MPPE-JG exhibited enhanced bioaccessibility, suggesting MPPE as a viable, functional ingredient in healthy gummies.

Microbiota-derived urolithin A in monoclonal gammopathies and multiple myeloma therapy

BACKGROUND

Gut microbiota-derived urolithins may influence multiple myeloma (MM) disease progression and treatment. We analyzed urolithins and their associated microbiota in a retrospective cohort of 45 patients with active MM or premalignant disease using mass spectrometry and 16S rRNA gene sequencing.

RESULTS

Patients with detectable levels of urolithin in serum and stool and a higher abundance of urolithin-related microbiota had a better outcome. Analysis of the effects of urolithin A (UroA) treatment ex vivo, in vitro, and in vivo revealed that UroA is cytotoxic against MM cell lines and modulates the cell cycle and mitochondrial activity. Notably, UroA inhibits the proliferation of primary MM cells in vitro and in a xenograft mouse model, improving overall survival. Finally, combination therapy with UroA and bortezomib has a synergistic effect in vitro, even in the presence of bortezomib resistance, and modulates signaling pathways involved in MM development.

CONCLUSIONS

UroA might be a potential therapeutic agent to halt MM disease progression or to overcome resistance when used in combination. Video Abstract.

Bacillusmegaterium DSM 32963 Enhances Specialized Pro-Resolving Mediator Production from an n-3 PUFA Salt in a Dynamic Model of the Human Intestine

BACKGROUND

Omega-3 polyunsaturated fatty acids (n-3 PUFA) have been used in the treatment of inflammatory bowel diseases (IBD) and irritable bowel syndrome (IBS), and their effects are potentiated upon conversion to specialized pro-resolving mediators (SPM). Recent studies indicated that the probiotic bacterial strain Bacillus megaterium DSM 32963 can be used to enhance the production of SPM and its precursors in vivo.

METHODS

Here, we explored the contribution of Bacillus megaterium DSM 32963 to SPM production in a validated, dynamic model of the upper and lower intestine. The TIM-1 and TIM-2 models were applied, with the TIM-2 model inoculated with the fecal microbiota of healthy individuals and probed with an n-3 PUFA lysine salt with and without Bacillus megaterium DSM 32963 or an SPM-enriched fish oil or placebo. Kinetics of SPM production were assessed by metabololipidomics analysis, and survival and engraftment of the Bacillus megaterium strain was monitored by plate counting and by strain-specific qPCR.

RESULTS

Bacillus megaterium DSM 32963 poorly survived TIM-1 conditions but propagated in the TIM-2 model, where it enabled the metabolism of n-3 PUFA to SPM (resolvin E2 and protectin DX) and SPM precursors (e.g., 5-hydroxyeicosapentaenoic acid (5-HEPE), 15-HEPE, 18-HEPE, 4-hydroxydocosahexaenoic acid (4-HDHA), 10-HDHA, and 17-HDHA, among other EPA- and DHA-derived metabolites) with significantly higher levels of lipid mediator production compared to the n-3 PUFA lysine salt alone; esterified n-3 PUFA were hardly converted by the microbiota.

CONCLUSIONS

These findings reinforce that Bacillus megaterium DSM 32963 facilitates SPM production in situ from bioavailable n-3 PUFA in the large intestine, highlighting its use to complement eukaryotic SPM biosynthesis by the host and its possible therapeutic use for, e.g., IBD and IBS.

Polyphenols and Microbiota Modulation: Insights from Swine and Other Animal Models for Human Therapeutic Strategies

High consumption of ultra-processed foods, rich in sugar and unhealthy fats, has been linked to the onset of numerous chronic diseases. Consequently, there has been a growing shift towards a fiber-rich diet, abundant in fruits, vegetables, seeds, and nuts, to enhance longevity and quality of life. The primary bioactive components in these plant-based foods are polyphenols, which exert significant effects on modulating the gastrointestinal microbiota through their antioxidant and anti-inflammatory activities. This modulation has preventive effects on neurodegenerative, metabolic, and cardiovascular diseases, and even cancer. The antimicrobial properties of polyphenols against pathogenic bacteria have significantly reduced the need for antibiotics, thereby lowering the risk of antibiotic resistance. This paper advances the field by offering novel insights into the beneficial effects of polyphenols, both directly through the metabolites produced during digestion and indirectly through changes in the host's gastrointestinal microbiota, uniquely emphasizing swine as a model highly relevant to human health, a topic that, to our knowledge, has not been thoroughly explored in previous reviews. This review also addresses aspects related to both other animal models (mice, rabbits, and rats), and humans, providing guidelines for future research into the benefits of polyphenol consumption. By linking agricultural and biomedical perspectives, it proposes strategies for utilizing these bioactive compounds as therapeutic agents in both veterinary and human health sciences.

Polyphenol-Derived Microbiota Metabolites and Cardiovascular Health: A Concise Review of Human Studies

Polyphenols, plant-derived secondary metabolites, play crucial roles in plant stress responses, growth regulation, and environmental interactions. In humans, polyphenols are associated with various health benefits, particularly in cardiometabolic health. Despite growing evidence of polyphenols' health-promoting effects, their mechanisms remain poorly understood due to high interindividual variability in bioavailability and metabolism. Recent research highlights the bidirectional relationship between dietary polyphenols and the gut microbiota, which can influence polyphenol metabolism and, conversely, be modulated by polyphenol intake. In this concise review, we summarized recent advances in this area, with a special focus on isoflavones and ellagitannins and their corresponding metabotypes, and their effect on cardiovascular health. Human observational studies published in the past 10 years provide evidence for a consistent association of isoflavones and ellagitannins and their metabotypes with better cardiovascular risk factors. However, interventional studies with dietary polyphenols or isolated microbial metabolites indicate that the polyphenol-gut microbiota interrelationship is complex and not yet fully elucidated. Finally, we highlighted various pending research questions that will help identify effective targets for intervention with precision nutrition, thus maximizing individual responses to dietary and lifestyle interventions and improving human health.

Ellagic acid ameliorates alcohol-induced cognitive and social dysfunction through the gut microbiota-mediated CCL21-CCR7 axis

Chronic alcohol consumption disrupts the balance of the gut microbiome, resulting in alcohol-induced cognitive and social dysfunction (AICSD), and serves as a primary etiological factor for early-onset dementia. Ellagic acid (EA) is a polyphenolic compound belonging to the ellagitannin family, showing potential as a dietary intervention for alleviating cognitive impairments. Nonetheless, the protective effects and underlying mechanisms of EA on AICSD remain unclear. In our study, we employed a multi-omics approach to elucidate the microbiome-mediated mechanism underlying the beneficial effects of EA on AICSD. Firstly, our findings demonstrate that EA significantly ameliorated cognitive and social behavioral deficits as well as neuroinflammation induced by alcohol. Moreover, RNA-seq analysis of hippocampi indicates that EA regulated the KEGG pathway of cytokine-cytokine receptor interaction signaling by downregulating the CCL21-CCR7 axis. Furthermore, we observed that EA effectively restored the dysbiosis of gut microbiota and their derived metabolites induced by chronic alcohol consumption. Strong connections were observed between EA-regulated genes, microbiota and metabolites. Finally, the causal relationship between the microbiome and behavioral changes was further confirmed through antibiotic treatment and fecal microbiota transplantation experiments. Overall, our study provides innovative evidence supporting the role of EA in improving AICSD via regulation of the cytokine-cytokine receptor interaction signaling pathway through the microbiota-mediated CCl21-CCR7 axis. These findings offer valuable insights into both EA-based interventions as well as microbial interventions against AICSD.

Perspective on the Coevolutionary Role of Host and Gut Microbiota in Polyphenol Health Effects: Metabotypes and Precision Health

"Personalized nutrition" aims to establish nutritional strategies to improve health outcomes for non-responders. However, it is utopian since most people share similar nutritional requirements. "Precision health," encompassing lifestyles, may be more fitting. Dietary (poly)phenols are "healthy" but non-nutritional molecules (thus, we can live without them). The gut microbiota influences (poly)phenol effects, producing metabolites with different activity than their precursors. Furthermore, producing distinctive metabolites, like urolithins, lunularin, and equol, leads to the term "polyphenol-related gut microbiota metabotypes," grouping individuals based on a genuine microbial metabolism of ellagic acid, resveratrol, and isoflavones, respectively. Additionally, (poly)phenols exert prebiotic-like effects through their antimicrobial activities, typically reducing microbial diversity and modulating microbiota functionality by impacting its composition and transcriptomics. Since the gut microbiota perceives (poly)phenols as a threat, (poly)phenol effects are mostly a consequence of microbiota adaptation through differential (poly)phenol metabolism (e.g., distinctive reductions, dehydroxylations, etc.). This viewpoint is less prosaic than considering (poly)phenols as essential nutritional players in human health, yet underscores their health significance in a coevolutionary partnership with the gut microbiota. In the perspective on the gut microbiota and (poly)phenols interplay, microbiota metabotypes could arbiter health effects. An innovative aspect is also emphasized: modulating the interacting microbial networks without altering the composition.

Strawberry (Fragaria x Ananassa) intake on human health and disease outcomes: a comprehensive literature review

Strawberries provide a number of potential health promoting phytonutrients to include phenolics, polyphenols, fiber, micronutrients and vitamins. The objective of this review is to provide a comprehensive summary of recent human studies pertaining to the intake of strawberry and strawberry phytonutrients on human health. A literature search conducted through PubMed and Cochrane databases consolidated studies focusing on the effects of strawberry intake on human health. Articles were reviewed considering pre-determined inclusion and exclusion criteria, including experimental or observational studies that focused on health outcomes, and utilized whole strawberries or freeze-dried strawberry powder (FDSP), published between 2000-2023. Of the 60 articles included in this review, 47 were clinical trials, while 13 were observational studies. A majority of these studies reported on the influence of strawberry intake on cardiometabolic outcomes. Study designs included those examining the influence of strawberry intake during the postprandial period, short-term trials randomized with a control, or a single arm intake period controlling with a low polyphenolic diet or no strawberry intake. A smaller proportion of studies included in this review examined the influence of strawberry intake on additional outcomes of aging including bone and brain health, and cancer risk. Data support that the inclusion of strawberries into the diet can have positive impacts during the postprandial period, with daily intake improving outcomes of lipid metabolism and inflammation in those at increased cardiovascular risk.

Pomegranate Juice Supplemented with Inulin Modulates Gut Microbiota and Promotes the Production of Microbiota-Associated Metabolites in Overweight/Obese Individuals: A Randomized, Double-Blind, Placebo-Controlled Trial

Pomegranate juice (PJ) and inulin have been reported to ameliorate diet-induced metabolic disorders by regulating gut microbiota dysbiosis. However, there was a lack of clinical evidence for the combined effects of PJ and inulin on regulating gut microbiota in individuals with metabolic disorders. A double-blind, parallel, randomized, placebo-controlled trial was conducted, and 68 overweight/obese individuals (25 ≤ BMI ≤ 35 kg/m2) were randomly assigned to receive 200 mL/d PJ, PJ supplemented with inulin, or placebo for 3 weeks. Our results showed that PJ and PJ+inulin did not significantly alter the levels of anthropometric and blood biochemical indicators after 3 weeks of treatment. However, there was an increasingly significant impact from placebo to PJ to PJ+inulin on the composition of gut microbiota. Detailed bacterial abundance analysis further showed that PJ+inulin treatment more profoundly resulted in significant changes in the abundance of gut microbiota at each taxonomic level than PJ. Moreover, PJ+inulin treatment also promoted the production of microbiota-associated short-chain fatty acids and pomegranate polyphenol metabolites, which correlated with the abundance of the bacterial genus. Our results suggested that PJ supplemented with inulin modulates gut microbiota composition and thus promotes the production of microbiota-associated metabolites that exert potential beneficial effects in overweight/obese subjects.

Dietary supplements: clinical cholesterol-lowering efficacy and potential mechanisms of action

This review aims to analyse the efficacy of dietary supplements in reducing plasma cholesterol levels. Focusing on evidence from meta-analyses of randomised controlled clinical trials, with an emphasis on potential mechanisms of action as supported by human, animal, and cell studies. Certain dietary supplements including phytosterols, berberine, viscous soluble dietary fibres, garlic supplements, soy protein, specific probiotic strains, and certain polyphenol extracts could significantly reduce plasma total and low-density lipoprotein (LDL) cholesterol levels by 3-25% in hypercholesterolemic patients depending on the type of supplement. They tended to be more effective in reducing plasma LDL cholesterol level in hypercholesterolemic individuals than in normocholesterolemic individuals. These supplements worked by various mechanisms, such as enhancing the excretion of bile acids, inhibiting the absorption of cholesterol in the intestines, increasing the expression of hepatic LDL receptors, suppressing the activity of enzymes involved in cholesterol synthesis, and activating the adenosine monophosphate-activated protein kinase signalling pathway.

Chronic consumption of orange juice modifies urinary excretion of flavanone gut-derived metabolites through gut microbiota modulation

The metabolism and absorption of citrus flavanones are intrinsically linked to the gut microbiota, creating a bidirectional relationship where these compounds influence the microbiome, and in turn, the microbiota affects their metabolism. This study evaluates the effect of acute and chronic consumption of orange juice (OJ) on the urinary excretion of gut-derived flavanone metabolites and the gut microbiota. Health volunteers ingested 500 mL of OJ for 60 days in a single-arm human intervention study. Blood and feces were collected at baseline and after 60 days, with an additional 24-hour urine collection after a single dose on day 1 and day 63. LC-MS/MS analyzed urinary flavanone metabolites, while 16S rRNA sequencing characterized gut microbiota. Total urinary hesperetin conjugates excretion significantly decreased over 60 days, while gut-derived total phenolic acids, particularly three hydroxybenzoic acids, increased. Moreover, the heterogeneity of the total amount of flavanone conjugates, initially categorizing individuals into high-, medium- and low- urinary excretor profiles, shifted towards medium-excretor, except for five individuals who remained as low-excretors. This alteration was accompanied by a decrease in intestinal β-glucosidase activity and a shift in the relative abundance of specific genera, such as decreases in Blautia, Eubacterium hallii, Anaerostipes, and Fusicatenibacter, among which, Blautia was associated with higher urinary flavanone conjugates excretion. Conversely, an increase in Prevotella was observed. In summary, chronic OJ consumption induced transient changes in gut microbiota and altered the metabolism of citrus flavanones, leading to distinct urinary excretion profiles of flavanone metabolites.

Factors driving the inter-individual variability in the metabolism and bioavailability of (poly)phenolic metabolites: A systematic review of human studies

This systematic review provides an overview of the available evidence on the inter-individual variability (IIV) in the absorption, distribution, metabolism, and excretion (ADME) of phenolic metabolites and its determinants. Human studies were included investigating the metabolism and bioavailability of (poly)phenols and reporting IIV. One hundred fifty-three studies met the inclusion criteria. Inter-individual differences were mainly related to gut microbiota composition and activity but also to genetic polymorphisms, age, sex, ethnicity, BMI, (patho)physiological status, and physical activity, depending on the (poly)phenol sub-class considered. Most of the IIV has been poorly characterised. Two major types of IIV were observed. One resulted in metabolite gradients that can be further classified into high and low excretors, as seen for all flavonoids, phenolic acids, prenylflavonoids, alkylresorcinols, and hydroxytyrosol. The other type of IIV is based on clusters of individuals defined by qualitative differences (producers vs. non-producers), as for ellagitannins (urolithins), isoflavones (equol and O-DMA), resveratrol (lunularin), and preliminarily for avenanthramides (dihydro-avenanthramides), or by quali-quantitative metabotypes characterized by different proportions of specific metabolites, as for flavan-3-ols, flavanones, and even isoflavones. Future works are needed to shed light on current open issues limiting our understanding of this phenomenon that likely conditions the health effects of dietary (poly)phenols.

(Poly)phenol-related gut metabotypes and human health: an update

Dietary (poly)phenols have received great interest due to their potential role in the prevention and management of non-communicable diseases. In recent years, a high inter-individual variability in the biological response to (poly)phenols has been demonstrated, which could be related to the high variability in (poly)phenol gut microbial metabolism existing within individuals. An interplay between (poly)phenols and the gut microbiota exists, with (poly)phenols being metabolised by the gut microbiota and their metabolites modulating gut microbiota diversity and composition. A number of (poly)phenol metabolising phenotypes or metabotypes have been proposed, however, potential metabotypes for most (poly)phenols have not been investigated, and the relationship between metabotypes and human health remains ambiguous. This review presents updated knowledge on the reciprocal interaction between (poly)phenols and the gut microbiome, associated gut metabotypes, and subsequent impact on human health.

Urolithin A production drives the effects of pomegranate on the gut microbial metabolism of bile acids and cholesterol in mild dyslipidaemic overweight and obese individuals

The metabolism of (poly)phenols and some host metabolites, including bile acids (BAs) and cholesterol, varies among individuals depending on their gut microbiota. The gut microbial metabolism of ellagitannins (ETs) and ellagic acid (EA) produces urolithins (Uros), yielding three metabotypes with quantitative and qualitative differences based on dissimilar Uro-producing profiles (UM-A, UM-B, and UM-0, i.e., non-producers). Previous animal studies demonstrated that polyphenols impact BAs and cholesterol microbial metabolism, but data on their effects in humans and data regarding the inter-individual variability of these metabolic conversions are scant. We evaluated whether UMs, as distinctive functional gut-microbiome signatures, could determine the potential effect of a pomegranate extract (PE) rich in ET-EA on the metabolism of BAs and cholesterol in mild dyslipidaemic overweight-obese individuals, with possible consequences on host-lipid homeostasis and gut health. At the baseline, UM-B presented the highest levels of faecal total and secondary BAs and coprostanol, suggesting that the lipid absorption capacity and gut cytotoxic risk could be augmented in UM-B. PE intake significantly reduced faecal coprostanol and BA production, especially secondary BAs, and modulated the gut microbiome, reducing the gut cytotoxic risk, especially in UM-B individuals. The lowering of faecal microbial coprostanol and BAs and some BA-metabolising bacteria was quantitatively correlated with Uro concentrations, mainly faecal Uro-A. This suggests that PE consumption could exert cardiovascular and gut protection through Uro-A production as a direct driver of the effects and indirectly by reducing the Coriobacteriaceae family and BA pool, known factors involved in the gut absorption of lipids.

The microbial metabolite urolithin A reduces Clostridioides difficile toxin expression and toxin-induced epithelial damage

Clostridioides difficile is a Gram-positive, anaerobic, spore-forming bacterium responsible for antibiotic-associated pseudomembranous colitis. Clostridioides difficile infection (CDI) symptoms can range from diarrhea to life-threatening colon damage. Toxins produced by C. difficile (TcdA and TcdB) cause intestinal epithelial injury and lead to severe gut barrier dysfunction, stem cell damage, and impaired regeneration of the gut epithelium. Current treatment options for intestinal repair are limited. In this study, we demonstrate that treatment with the microbial metabolite urolithin A (UroA) attenuates CDI-induced adverse effects on the colon epithelium in a preclinical model of CDI-induced colitis. Moreover, our analysis suggests that UroA treatment protects against C. difficile-induced inflammation, disruption of gut barrier integrity, and intestinal tight junction proteins in the colon of CDI mice. Importantly, UroA treatment significantly reduced the expression and release of toxins from C. difficile without inducing bacterial cell death. These results indicate the direct regulatory effects of UroA on bacterial gene regulation. Overall, our findings reveal a novel aspect of UroA activity, as it appears to act at both the bacterial and host levels to protect against CDI-induced colitis pathogenesis. This research sheds light on a promising avenue for the development of novel treatments for C. difficile infection.IMPORTANCETherapy for Clostridioides difficile infections includes the use of antibiotics, immunosuppressors, and fecal microbiota transplantation. However, these treatments have several drawbacks, including the loss of colonization resistance, the promotion of autoimmune disorders, and the potential for unknown pathogens in donor samples. To date, the potential benefits of microbial metabolites in CDI-induced colitis have not been fully investigated. Here, we report for the first time that the microbial metabolite urolithin A has the potential to block toxin production from C. difficile and enhance gut barrier function to mitigate CDI-induced colitis.

Mechanisms of gut bacterial metabolism of dietary polyphenols into bioactive compounds

The fruits and vegetables we consume as part of our diet are rich in bioactive metabolites that can prevent and ameliorate cardiometabolic diseases, cancers, and neurological conditions. Polyphenols are a major metabolite family that has been intensively investigated in this context. However, for these compounds to exert their optimal bioactivity, they rely on the enzymatic capacity of an individual's gut microbiota. Indeed, for most polyphenols, the human host is restricted to more basic metabolism such as deglycosylation and hepatic conjugation. In this review, we discuss the mechanisms by which gut bacteria metabolize the core scaffold of polyphenol substrates, and how their conversion into bioactive small molecules impacts host health.

Exploring substrate-microbe interactions: a metabiotic approach toward developing targeted synbiotic compositions

Gut microbiota is an important modulator of human health and contributes to high inter-individual variation in response to food and pharmaceutical ingredients. The clinical outcomes of interventions with prebiotics, probiotics, and synbiotics have been mixed and often unpredictable, arguing for novel approaches for developing microbiome-targeted therapeutics. Here, we review how the gut microbiota determines the fate of and individual responses to dietary and xenobiotic compounds via its immense metabolic potential. We highlight that microbial metabolites play a crucial role as targetable mediators in the microbiota-host health relationship. With this in mind, we expand the concept of synbiotics beyond prebiotics' role in facilitating growth and engraftment of probiotics, by focusing on microbial metabolism as a vital mode of action thereof. Consequently, we discuss synbiotic compositions that enable the guided metabolism of dietary or co-formulated ingredients by specific microbes leading to target molecules with beneficial functions. A workflow to develop novel synbiotics is presented, including the selection of promising target metabolites (e.g. equol, urolithin A, spermidine, indole-3 derivatives), identification of suitable substrates and producer strains applying bioinformatic tools, gut models, and eventually human trials.In conclusion, we propose that discovering and enabling specific substrate-microbe interactions is a valuable strategy to rationally design synbiotics that could establish a new category of hybrid nutra-/pharmaceuticals.

Identifying subgroups of childhood obesity by using multiplatform metabotyping

Introduction: Obesity results from an interplay between genetic predisposition and environmental factors such as diet, physical activity, culture, and socioeconomic status. Personalized treatments for obesity would be optimal, thus necessitating the identification of individual characteristics to improve the effectiveness of therapies. For example, genetic impairment of the leptin-melanocortin pathway can result in rare cases of severe early-onset obesity. Metabolomics has the potential to distinguish between a healthy and obese status; however, differentiating subsets of individuals within the obesity spectrum remains challenging. Factor analysis can integrate patient features from diverse sources, allowing an accurate subclassification of individuals. Methods: This study presents a workflow to identify metabotypes, particularly when routine clinical studies fail in patient categorization. 110 children with obesity (BMI > +2 SDS) genotyped for nine genes involved in the leptin-melanocortin pathway (CPE, MC3R, MC4R, MRAP2, NCOA1, PCSK1, POMC, SH2B1, and SIM1) and two glutamate receptor genes (GRM7 and GRIK1) were studied; 55 harboring heterozygous rare sequence variants and 55 with no variants. Anthropometric and routine clinical laboratory data were collected, and serum samples processed for untargeted metabolomic analysis using GC-q-MS and CE-TOF-MS and reversed-phase U(H)PLC-QTOF-MS/MS in positive and negative ionization modes. Following signal processing and multialignment, multivariate and univariate statistical analyses were applied to evaluate the genetic trait association with metabolomics data and clinical and routine laboratory features. Results and Discussion: Neither the presence of a heterozygous rare sequence variant nor clinical/routine laboratory features determined subgroups in the metabolomics data. To identify metabolomic subtypes, we applied Factor Analysis, by constructing a composite matrix from the five analytical platforms. Six factors were discovered and three different metabotypes. Subtle but neat differences in the circulating lipids, as well as in insulin sensitivity could be established, which opens the possibility to personalize the treatment according to the patients categorization into such obesity subtypes. Metabotyping in clinical contexts poses challenges due to the influence of various uncontrolled variables on metabolic phenotypes. However, this strategy reveals the potential to identify subsets of patients with similar clinical diagnoses but different metabolic conditions. This approach underscores the broader applicability of Factor Analysis in metabotyping across diverse clinical scenarios.

Polyphenol and glucosinolate-derived AhR modulators regulate GPR15 expression on human CD4+ T cells

Diets high in fruit and vegetables are perceived to be beneficial for intestinal homeostasis, in health as well as in the context of inflammatory bowel diseases (IBDs). Recent breakthroughs in the field of immunology have highlighted the importance of the ligand-activated transcription factor aryl hydrocarbon receptor (AhR) as a critical regulator of mucosal immunity, including the intestinal trafficking of CD4+ helper T cells, an immune cell subset implicated in a wide range of homeostatic and pathogenic processes. Specifically, the AhR has been shown to directly regulate the expression of the chemoattractant receptor G Protein-Coupled Receptor 15 (GPR15) on CD4+ T cells. GPR15 is an important gut homing marker whose expression on CD4+ T cells in the peripheral circulation is elevated in patients suffering from ulcerative colitis, raising the possibility that, in this setting, the beneficial effect of a diet rich in fruits and vegetables may be mediated through the modulation of GPR15 expression. To address this, we screened physiologically-relevant polyphenol and glucosinolate metabolites for their ability to affect both AhR activity and GPR15 expression. Our complementary approach and associated findings suggest that polyphenol and glucosinolate metabolites can regulate GPR15 expression on human CD4+ T cells in an AhR-dependent manner.

Effect of Ginger Root Powder on Gastrointestinal Bacteria Composition, Gastrointestinal Symptoms, Mental Health, Fatigue, and Quality of Life: A Double-Blind Placebo-Controlled Trial

BACKGROUND

Despite compositional alterations in gastrointestinal microbiota being purported to underpin some of the therapeutic effects of ginger, the effect of a standardized ginger supplement on gut microbiota has not been tested in humans.

OBJECTIVES

To determine the effect of a standardized ginger (Zingiber officinale) root powder, compared to placebo, on gastrointestinal bacteria and associated outcomes in healthy adults.

METHODS

A randomized double-blind placebo-controlled trial allocated participants aged 18 to 30 y to ginger or microcrystalline cellulose (MCC) placebo. The intervention comprised 1.2 g/d of ginger (4 capsules per day totaling 84 mg/d of active gingerols/shogaols) for 14 d following a 1-wk run-in period. Primary outcomes were gastrointestinal community composition, alpha and beta diversity, and differential abundance, measured using 16S rRNA gene sequencing of fecal samples. Secondary outcomes were gastrointestinal symptoms, bowel function, depression, anxiety, stress, fatigue, quality of life, and adverse events.

RESULTS

Fifty-one participants were enrolled and analyzed (71% female; mean age 25 ± 3 y; ginger: n = 29, placebo: n = 22). There was a greater increase in relative abundance of phylum, Actinobacteria, observed following ginger supplementation compared to placebo (U: 145.0; z: -2.1; P = 0.033). Ginger was associated with a greater abundance of the genera Parabacteroides, Bacillus, Ruminococcaceae incertae sedis, unclassified Bacilli, families Defluviitaleaceae, Morganellaceae, and Bacillaceae as well as lower abundance of the genus Blautia and family Sphingomonadaceae (P < 0.05). An improvement in indigestion symptoms was observed with ginger supplementation (U: 196.0; z: -2.4; P = 0.015). No differences between ginger and placebo groups were found for alpha and beta diversity or other secondary outcomes. No moderate or severe adverse events were reported.

CONCLUSIONS

Supplementation with ginger root powder was safe and altered aspects of gastrointestinal bacteria composition; however, it did not change alpha- or beta diversity, bowel function, gastrointestinal symptoms, mood, or quality of life in healthy adults. These results provide further understanding regarding the mechanisms of action of ginger supplementation. This trial was registered in the Australia New Zealand Clinical Trials Registry as ACTRN12620000302954p and the Therapeutic Goods Administration as CT-2020-CTN-00380-1.

Unveiling metabotype clustering in resveratrol, daidzein, and ellagic acid metabolism: Prevalence, associated gut microbiomes, and their distinctive microbial networks

The gut microbiota (GM) produces different polyphenol-derived metabolites, yielding high interindividual variability and hampering consistent health effects. GM metabotypes associated with ellagic acid (urolithin metabotypes A (UMA), B (UMB), and 0 (UM0)), resveratrol (lunularin -producers (LP) and non-producers (LNP)), and daidzein (equol-producers (EP) and non-producers (ENP)) are known. However, individual polyphenol-related metabotypes do not occur individually. In contrast, different combinations coexist (i.e., metabotype clusters, MCs). We report here for the first time these MCs, their distribution, and their associated GM in adult humans (n = 127) after consuming for 7 days a nutraceutical (pomegranate, Polygonum cuspidatum, and red clover extracts) containing ellagitannins + ellagic acid, resveratrol, and isoflavones. Urine metabolites (UHPLC-QTOF-MS) and fecal microbiota (16S rRNA sequencing) were analyzed. Ten MCs were identified: LP + UMB + ENP (22.7%), LP + UMA + ENP (21.3%), LP + UMA + EP (16.7%), LP + UMB + EP (16%), LNP + UMA + ENP (11.3%), LNP + UMB + ENP (5.3%), LNP + UMA + EP (3.3%), LNP + UMB + EP (2%), LNP + UM0 + EP (0.7%), and LNP + UM0 + ENP (0.7%). Sex, BMI, and age did not affect the distribution of metabotypes or MCs. Multivariate analysis (MaAslin2) revealed genera differentially present in individual metabotypes and MCs. Network analysis (MENA) showed the taxa acting as module hubs and connectors. Compositional and functional profiling, alpha and beta diversities, topological network features, and GM modulation by the nutraceutical differed depending on whether the entire cohort or each MC was considered. The nutraceutical did not change the composition of LP + UMA + EP (the most robust GM with the most associated functions) but increased its network connectors. This pioneering approach, joining GM's compositional, functional, and network features in polyphenol metabolism, paves the way for identifying personalized GM-targeted strategies to improve polyphenol health benefits.

Unravelling phenolic metabotypes in the frame of the COMBAT study, a randomized, controlled trial with cranberry supplementation

Cranberry (poly)phenols may have potential health benefits. Circulating (poly)phenol metabolites can act as mediators of these effects, but they are subjected to an extensive inter-individual variability. This study aimed to quantify both plasma and urine (poly)phenol metabolites following a 12-week intake of a cranberry powder in healthy older adults, and to investigate inter-individual differences by considering the existence of urinary metabotypes related to dietary (poly)phenols. Up to 13 and 67 metabolites were quantified in plasma and urine respectively. Cranberry consumption led to changes in plasma metabolites, mainly hydroxycinnamates and hippuric acid. Individual variability in urinary metabolites was assessed using different data sets and a combination of statistical models. Three phenolic metabotypes were identified, colonic metabolism being the main driver for subject clustering. Metabotypes were characterized by quali-quantitative differences in the excretion of some metabolites such as phenyl-γ-valerolactones, hydroxycinnamic acids, and phenylpropanoic acids. Metabotypes were further confirmed when applying a model only focused on flavan-3-ol colonic metabolites. 5-(3',4'-dihydroxyphenyl)-γ-valerolactone derivatives were the most relevant metabolites for metabotyping. Metabotype allocation was well preserved after 12-week intervention. This metabotyping approach for cranberry metabolites represents an innovative step to handle the complexity of (poly)phenol metabolism in free-living conditions, deciphering the existence of metabotypes derived from the simultaneous consumption of different classes of (poly)phenols. These results will help contribute to studying the health effects of cranberries and other (poly)phenol-rich foods, mainly considering gut microbiota-driven individual differences.

NMR Spectroscopic Identification of Urolithin G, a Novel Trihydroxy Urolithin Produced by Human Intestinal Enterocloster Species

Urolithins are gut microbiota metabolites of ellagic acid. Here, we have identified and chemically characterized a novel urolithin produced from urolithin D (3,4,8,9-tetrahydroxy urolithin) by in vitro incubation with different human gut Enterocloster species under anaerobic conditions. Urolithin G (3,4,8-trihydroxy urolithin) was identified by 1H NMR, 13C NMR, UV, HRMS, and 2D NMR. For the identification, NMR spectra of other known urolithins were also recorded and compared. Urolithin G was present in the feces of 12% of volunteers in an overweight-obese group after consuming an ellagitannin-rich pomegranate extract. The production of urolithin G required a bacterial 9-dehydroxylase activity and was not specific to the known human urolithin metabotypes A and B. The ability to produce urolithin G could be considered an additional metabolic feature for volunteer stratification and bioactivity studies. This is the first urolithin with a catechol group in ring A while having only one hydroxyl in ring B, a unique feature not found in human and animal samples so far.

The microbial metabolite Urolithin A reduces C. difficile toxin expression and repairs toxin-induced epithelial damage

Clostridioides difficile is a gram-positive, anaerobic, spore-forming bacterium that is responsible for antibiotic-associated pseudomembranous colitis. Clostridioides difficile infection (CDI) symptoms can range from diarrhea to life-threatening colon damage. Toxins produced by C. difficile (TcdA and TcdB) cause intestinal epithelial injury and lead to severe gut barrier dysfunction, stem cell damage, and impaired regeneration of the gut epithelium. Current treatment options for intestinal repair are limited. In this study, we demonstrate that treatment with the microbial metabolite urolithin A (UroA) attenuates CDI-induced adverse effects on the colon epithelium in a preclinical model of CDI-induced colitis. Moreover, our analysis suggests that UroA treatment protects against C. difficile-induced inflammation, disruption of gut barrier integrity, and intestinal tight junction proteins in the colon of CDI mice. Importantly, UroA treatment significantly reduced the expression and release of toxins from C. difficile, without inducing bacterial cell death. These results indicate the direct regulatory effects of UroA on bacterial gene regulation. Overall, our findings reveal a novel aspect of UroA activities, as it appears to act at both the bacterial and host levels to protect against CDI-induced colitis pathogenesis. This research sheds light on a promising avenue for the development of novel treatments for C. difficile infection.

Bioavailable Microbial Metabolites of Flavanols Demonstrate Highly Individualized Bioactivity on In Vitro β-Cell Functions Critical for Metabolic Health

Dietary flavanols are known for disease preventative properties but are often poorly absorbed. Gut microbiome flavanol metabolites are more bioavailable and may exert protective activities. Using metabolite mixtures extracted from the urine of rats supplemented with flavanols and treated with or without antibiotics, we investigated their effects on INS-1 832/13 β-cell glucose stimulated insulin secretion (GSIS) capacity. We measured insulin secretion under non-stimulatory (low) and stimulatory (high) glucose levels, insulin secretion fold induction, and total insulin content. We conducted treatment-level comparisons, individual-level dose responses, and a responder vs. non-responder predictive analysis of metabolite composition. While the first two analyses did not elucidate treatment effects, metabolites from 9 of the 28 animals demonstrated significant dose responses, regardless of treatment. Differentiation of responders vs. non-responder revealed that levels of native flavanols and valerolactones approached significance for predicting enhanced GSIS, regardless of treatment. Although treatment-level patterns were not discernable, we conclude that the high inter-individual variability shows that metabolite bioactivity on GSIS capacity is less related to flavanol supplementation or antibiotic treatment and may be more associated with the unique microbiome or metabolome of each animal. These findings suggest flavanol metabolite activities are individualized and point to the need for personalized nutrition practices.

Crosstalk between dietary pomegranate and gut microbiota: evidence of health benefits

Gut microbiota (GM) is an invisible organ that plays an important role in human health. Increasing evidence suggests that polyphenols in pomegranate (punicalagin, PU) could serve as prebiotics to modulate the composition and function of GM. In turn, GM transform PU into bioactive metabolites such as ellagic acid (EA) and urolithin (Uro). In this review, the interplay between pomegranate and GM is thoroughly described by unveiling a dialog in which both actors seem to affect each other's roles. In a first dialog, the influence of bioactive compounds from pomegranate on GM is described. The second act shows how the GM biotransform pomegranate phenolics into Uro. Finally, the health benefits of Uro and that related molecular mechanism are summarized and discussed. Intake of pomegranate promotes beneficial bacteria in GM (e.g. Lactobacillus spp., Bifidobacterium spp.) while reducing the growth of harmful bacteria (e.g. Bacteroides fragilis group, Clostridia). Akkermansia muciniphila, and Gordonibacter spp., among others, biotransform PU and EA into Uro. Uro contributes to strengthening intestinal barrier and reducing inflammatory processes. Yet, Uro production varies greatly among individuals and depend on GM composition. Uro-producing bacteria and precise metabolic pathways need to be further elucidated therefore contributing to personalized and precision nutrition.

Accounting Gut Microbiota as the Mediator of Beneficial Effects of Dietary (Poly)phenols on Skeletal Muscle in Aging

Sarcopenia, the age-related loss of muscle mass and function increasing the risk of disability and adverse outcomes in older people, is substantially influenced by dietary habits. Several studies from animal models of aging and muscle wasting indicate that the intake of specific polyphenol compounds can be associated with myoprotective effects, and improvements in muscle strength and performance. Such findings have also been confirmed in a smaller number of human studies. However, in the gut lumen, dietary polyphenols undergo extensive biotransformation by gut microbiota into a wide range of bioactive compounds, which substantially contribute to bioactivity on skeletal muscle. Thus, the beneficial effects of polyphenols may consistently vary across individuals, depending on the composition and metabolic functionality of gut bacterial communities. The understanding of such variability has recently been improved. For example, resveratrol and urolithin interaction with the microbiota can produce different biological effects according to the microbiota metabotype. In older individuals, the gut microbiota is frequently characterized by dysbiosis, overrepresentation of opportunistic pathogens, and increased inter-individual variability, which may contribute to increasing the variability of biological actions of phenolic compounds at the skeletal muscle level. These interactions should be taken into great consideration for designing effective nutritional strategies to counteract sarcopenia.

Changes in the Gut Microbiota after the Use of Herbal Medicines in Overweight and Obese Individuals: A Systematic Review

BACKGROUND

Herbal medicine is a low-cost treatment and has been increasingly applied in obesity treatment. Gut microbiota (GM) is strongly associated with obesity pathogenesis.

METHODS

We conducted a systematic review guided by the question: "Does the use of herbal medicine change the GM composition in obese individuals?" Randomized clinical trials with obese individuals assessing the effects of herbal medicine intervention in GM were retrieved from the Medline, Embase, Scopus, Web of Science, and Cochrane Library databases, including the Cochrane Controlled Trials Register. Two reviewers independently extracted data using standardized piloted data extraction forms and assessed the study-level risk of bias using an Excel template of the Cochrane "Risk of bias" tool 2-RoB 2.

RESULTS

We identified 1094 articles in the databases. After removing duplicates and reading the title and abstract, 14 publications were fully evaluated, of which seven publications from six studies were considered eligible. The herbs analyzed were Moringa oleifera, Punica granatum, Scutellaria baicalensis, Schisandra chinensis, W-LHIT and WCBE. The analysis showed that Schisandra chinensis and Scutellaria baicalensis had significant effects on weight loss herbal intervention therapy composed by five Chinese herbal medicines Ganoderma lucidum, Coptis chinensis, Astragalus membranaceus, Nelumbo nucifera gaertn, and Fructus aurantii (W-LHIT) and white common bean extract (WCBE) on GM, but no significant changes in anthropometry and laboratory biomarkers.

CONCLUSIONS

Herbal medicine modulates GM and is associated with increased genera in obese individuals.

In vivo administration of gut bacterial consortia replicates urolithin metabotypes A and B in a non-urolithin-producing rat model

Urolithin (Uro) production capacity and, consequently, at least partly, the health effects attributed to ellagitannin and ellagic acid consumption vary among individuals. The reason is that not all individuals have the gut bacterial ecology needed to produce the different Uro metabolites. Three human urolithin metabotypes (UM-A, UM-B, and UM-0) based on dissimilar Uro production profiles have been described in populations worldwide. Recently, the gut bacterial consortia involved in ellagic acid metabolism to yield the urolithin-producing metabotypes (UM-A and UM-B) in vitro have been identified. However, the ability of these bacterial consortia to customize urolithin production to mimic UM-A and UM-B in vivo is still unknown. In the present study, two bacterial consortia were assessed for their capacity to colonize the intestine of rats and convert UM-0 (Uro non-producers) animals into Uro-producers that mimic UM-A and UM-B, respectively. Two consortia of Uro-producing bacteria were orally administered to non-urolithin-producing Wistar rats for 4 weeks. Uro-producing bacterial strains effectively colonized the rats' gut, and the ability to produce Uros was also effectively transferred. Bacterial strains were well tolerated. No changes in other gut bacteria, except Streptococcus reduction, or adverse effects on haematological and biochemical parameters were observed. Besides, two novel qPCR procedures were designed and successfully optimized to detect and quantify Ellagibacter and Enterocloster genera in faecal samples. These results suggest that the bacterial consortia are safe and could be potential probiotics for human trials, which is especially relevant for UM-0 individuals, who cannot produce bioactive Uros.

Metabolomics signatures of plant protein intake: effects of amino acids and compounds associated with plant protein on cardiometabolic health

PURPOSE OF REVIEW

An increase in the plant-based characteristics of the diet is now recommended for human and planetary health. There is growing evidence that plant protein (PP) intake has beneficial effects on cardiometabolic risk. However, proteins are not consumed isolated and the protein package (lipid species, fiber, vitamins, phytochemicals, etc) may contribute, besides the protein effects per se, to explain the beneficial effects associated with PP-rich diets.

RECENT FINDINGS

Recent studies have shown the potential of nutrimetabolomics to apprehend the complexity of both the human metabolism and the dietary habits, by providing signatures associated to the consumption of PP-rich diets. Those signatures comprised an important proportion of metabolites that were representative of the protein package, including specific amino acids (branched-chain amino acids and their derivates, glycine, lysine), but also lipid species (lysophosphatidylcholine, phosphatidylcholine, plasmalogens) and polyphenol metabolites (catechin sulfate, conjugated valerolactones and phenolic acids).

SUMMARY

Further studies are needed to go deeper in the identification of all metabolites making part of the specific metabolomic signatures, associated to the large range of protein package constituents and their effects on the endogenous metabolism, rather than to the protein fraction itself. The objective is to determine the bioactive metabolites, as well as the modulated metabolic pathways and the mechanisms responsible for the observed effects on cardiometabolic health.

Randomized Double-Blind Placebo-Controlled Supplementation with Standardized Terminalia chebula Fruit Extracts Reduces Facial Sebum Excretion, Erythema, and Wrinkle Severity

Terminalia chebula (TC) is a medicinal plant that exhibits antioxidant, anti-inflammatory, and antibacterial properties and that is widely used in Ayurveda and herbal formulations. However, the skin effects of TC as an oral supplement have not been studied. The objective of this study is to determine if oral TC fruit extract supplementation can modulate the skin's sebum production and reduce the appearance of wrinkles. A prospective double-blind placebo-controlled study was conducted on healthy females aged 25-65. Subjects were supplemented with an oral placebo or Terminalia chebula (250 mg capsule, Synastol TC) capsules twice daily for eight weeks. A facial image collection and analysis system was used to assess the facial appearance of wrinkle severity. Standardized, non-invasive tools were used to measure facial moisture, sebum production, transepidermal water loss, melanin index and erythema index. For those who had a baseline sebum excretion rate >80 ug/cm², TC supplementation produced a significant decrease in forehead sebum excretion rate compared to the placebo at four weeks (-17 decrease vs. 20% increase, p = 0.07) and at eight weeks (-33% decrease vs. 29% increase, p < 0.01). Cheek erythema decreased by 2.2% at eight weeks, while the placebo treatment increased cheek erythema by 1.5% (p < 0.05). Facial wrinkles decreased by 4.3% in the TC group and increased by 3.9% in the placebo group after eight weeks of supplementation (p < 0.05). TC supplementation reduces facial sebum and improves the appearance of wrinkles. Future studies should consider evaluating oral TC as adjuvant therapy for acne vulgaris.

Ellagitannins, urolithins, and neuroprotection: Human evidence and the possible link to the gut microbiota

Ellagitannins (ETs) and ellagic acid (EA) are dietary polyphenols poorly absorbed but extensively metabolized by the human gut microbiota to produce different urolithins (Uros). Depending on the individuals' microbial signatures, ETs metabolism can yield the Uro metabotypes A, B, or 0, potentially impacting human health after consuming ETs. Human evidence points to improved brain health after consuming ET-rich foods, mainly pomegranate juices and extracts containing punicalagin, punicalin, and different EA-derivatives. Although ETs and (or) EA are necessary to exert the effects, the precise mechanism, actual metabolites, or final drivers responsible for the observed effects have not been unraveled. The cause-and-effect evidence on Uro-A administration and the improvement of animal brain health is consistent but not addressed in humans. The Uro-A's in vivo anti-inflammatory, mitophagy, autophagy, and mitochondrial biogenesis activities suggest it as a possible final driver in neuroprotection. However, the precise Uro metabolic forms reaching the brain are unknown. In addition to the possible participation of direct effectors in brain tissues, the current evidence points out that improving blood flow, gut microbiota ecology, and gut barrier by ET-rich foods and (or) Uro-A could contribute to the neuroprotective effects. We show here the current human evidence on ETs and brain health, the possible link between the gut microbiota metabolism of ETs and their effects, including the preservation of the gut barrier integrity, and the possible role of Uros. Finally, we propose a roadmap to address what is missing on ETs, Uros, and neuroprotection.

Distinctive anti-inflammatory effects of resveratrol, dihydroresveratrol, and 3-(4-hydroxyphenyl)-propionic acid on DSS-induced colitis in pseudo-germ-free mice

Resveratrol is a dietary polyphenol that interacts with gut microbiota to possess various biological activities. To identify the microbial metabolites of resveratrol, fresh feces from 12 volunteers were cultured in vitro. Their urine samples were collected after taking a commercial capsule containing 600 mg of resveratrol. Metabolites were characterized and quantified by UPLC-Q-Exactive plus orbitrap MS/MS. The results showed that dihydroresveratrol, 3-(4-hydroxyphenyl)-propionic acid, and lunularin were the major microbial metabolites of RSV with interindividual differences. 3-(4-Hydroxyphenyl)-propionic acid significantly attenuated the inflammatory response of LPS-treated RAW264.7 cells and DSS-induced colitis in antibiotics-treated pseudo-germ-free mice by regulating MAPK and NF-κB pathways. In contrast, dihydroresveratrol did not exhibit significant anti-inflammatory effects, and lunularin exhibited pro-inflammatory effects in cells. This study may help to better understand the health effects of resveratrol and its microbial metabolites.

The Impact of Ellagitannins and Their Metabolites through Gut Microbiome on the Gut Health and Brain Wellness within the Gut-Brain Axis

Ellagitannins (ETs) are a large group of bioactive compounds found in plant-source foods, such as pomegranates, berries, and nuts. The consumption of ETs has often been associated with positive effects on many pathologies, including cardiovascular diseases, neurodegenerative syndromes, and cancer. Although multiple biological activities (antioxidant, anti-inflammatory, chemopreventive) have been discussed for ETs, their limited bioavailability prevents reaching significant concentrations in systemic circulation. Instead, urolithins, ET gut microbiota-derived metabolites, are better absorbed and could be the bioactive molecules responsible for the antioxidant and anti-inflammatory activities or anti-tumor cell progression. In this review, we examined the dietary sources, metabolism, and bioavailability of ETs, and analyzed the last recent findings on ETs, ellagic acid, and urolithins, their intestinal and brain activities, the potential mechanisms of action, and the connection between the ET microbiota metabolism and the consequences detected on the gut-brain axis. The current in vitro, in vivo, and clinical studies indicate that ET-rich foods, individual gut microbiomes, or urolithin types could modulate signaling pathways and promote beneficial health effects. A better understanding of the role of these metabolites in disease pathogenesis may assist in the prevention or treatment of pathologies targeting the gut-brain axis.

Can exosomes transfer the preconditioning effects triggered by (poly)phenol compounds between cells?

Effective strategies in prolonging life- and health span are increasingly recognized as acting as mild stressors. Micronutrients and other dietary compounds such as (poly)phenols may act as moderate stressors and confer protective effects via a preconditioning phenomenon. (Poly)phenols and their metabolites may not need to reach their target cells to produce biologically significant responses, so that cells exposed to it at entry points may communicate signals to other cells. One of such "communication" mechanisms could occur through extracellular vesicles, including exosomes. In vitro loading of exosomes with (poly)phenols has been used to achieve targeted exosome homing. However, it is unknown if similar shuttling phenomena occur in vivo upon (poly)phenols consumption. Alternatively, exposure to (poly)phenols might trigger responses in exposed organs, which can subsequently signal to cells distant from exposure sites via exosomes. The currently available studies favor indirect effects of (poly)phenols, tempting to suggest a "billiard-like" or "domino-like" propagating effect mediated by quantitative and qualitative changes in exosomes triggered by (poly)phenols. In this review, we discuss the limited current data available on how (poly)phenols exposure can potentially modify exosomes activity, highlighting major questions regarding how (epi)genetic, physiological, and gut microbiota factors can modulate and be modulated by the putative exosome-(poly)phenolic compound interplay that still remains to be fully understood.

Urolithins: a Comprehensive Update on their Metabolism, Bioactivity, and Associated Gut Microbiota

Urolithins, metabolites produced by the gut microbiota from the polyphenols ellagitannins and ellagic acid, are discovered by the research group in humans almost 20 years ago. Pioneering research suggests urolithins as pleiotropic bioactive contributors to explain the health benefits after consuming ellagitannin-rich sources (pomegranates, walnuts, strawberries, etc.). Here, this study comprehensively updates the knowledge on urolithins, emphasizing the review of the literature published during the last 5 years. To date, 13 urolithins and their corresponding conjugated metabolites (glucuronides, sulfates, etc.) have been described and, depending on the urolithin, detected in different human fluids and tissues (urine, blood, feces, breastmilk, prostate, colon, and breast tissues). There has been a substantial advance in the research on microorganisms involved in urolithin production, along with the compositional and functional characterization of the gut microbiota associated with urolithins metabolism that gives rise to the so-called urolithin metabotypes (UM-A, UM-B, and UM-0), relevant in human health. The design of in vitro studies using physiologically relevant assay conditions (molecular forms and concentrations) is still a pending subject, making some reported urolithin activities questionable. In contrast, remarkable progress has been made in the research on the safety, bioactivity, and associated mechanisms of urolithin A, including the first human interventions.

Mixed Tree Nuts, Cognition, and Gut Microbiota: A 4-Week, Placebo-Controlled, Randomized Crossover Trial in Healthy Nonelderly Adults

BACKGROUND

Beneficial effects of nut supplementation on cognitive function have previously been demonstrated in young and older adults. Alterations to gut microbiota have also been shown following tree nut consumption. However, no data exists on the effects of nuts on cognition and intestinal microbial communities assessed within the same study.

OBJECTIVES

The study aimed to examine the effects of daily consumption of tree nuts for 4 wk on cognitive function (primary outcome), mood, metabolomics, and gut microbial species (secondary outcomes) in healthy, nonelderly adults.

METHODS

This randomized, placebo-controlled, double-blind, counterbalanced crossover study assessed the effects of 4 wk of supplementation with 30 g/d mixed tree nuts versus placebo on cognition and mood in 79 healthy adults aged 18-49 y. Metabolic responses, gut bacterial community structure, and the potential for these to impact cognition were explored using a multi-omic approach. Bacterial community analysis was conducted in Quantitative Insights Into Microbial Ecology 2 (QIIME2).

RESULTS

Mixed model analysis indicated that nut consumption led to significant improvements to accuracy (placebo M = 92.2% compared with NUTS M = 94.5%; P = 0.019) and speed of response (placebo M = 788 ms compared with NUTS M = 757 ms; P = 0.004) on a picture recognition task. No significant changes to bacterial community α or β diversity were observed when comparing nut consumption to the placebo arm. However, an unclassified Lachnospiraceae amplicon sequence variant (ASV) was significantly enriched in participants when supplemented with nuts (P = 0.015). No correlations were observed between the changes to picture recognition and the changes to the unclassified Lachnospiraceae ASV. There were no significant changes to the urinary metabolome.

CONCLUSIONS

These findings indicate a positive effect of nut on cognition following only 4 wk of consumption in a healthy nonelderly sample, as well as upregulation of a microbial taxa associated with gut health. The effects appear to be independent of one another, but further exploration is required in those experiencing cognitive decline and/or gut dysbiosis.

Polyphenols and atherosclerosis: A critical review of clinical effects on LDL oxidation

Atherosclerosis is a major etiology of cardiovascular disease that causes considerable mortality. Oxidized low-density lipoprotein (oxLDL) is a fundamental attributor to atherosclerosis. Therefore, there seems to be an essential place for antioxidant therapy besides the current treatment protocols for coronary heart disease. Polyphenols are a class of compounds with substantial antioxidant properties that have shown the ability to reduce LDL oxidation in preclinical studies. However, clinical evidence has not been as conclusive although offering many promising signs. This review aims to examine the trials that have evaluated how dietary intake of polyphenols in different forms might influence the oxidation of LDL. Lowering the circulating cholesterol, incorporation into LDL particles, and enhancing systemic antioxidant activity are among the main mechanisms of action for polyphenols for lowering oxLDL. On the other hand, the population under study significantly affects the impact on oxLDL, as the type of the supplement and phenolic content. To conclude, although the polyphenols might decrease inflammation and enhance endothelial function via lowering oxLDL, there are still many gaps in our knowledge that need to be filled with further high-quality studies.

Differential Protective Effect of Resveratrol and Its Microbial Metabolites on Intestinal Barrier Dysfunction is Mediated by the AMPK Pathway

The effectiveness of resveratrol (RES) on intestinal barrier dysfunction and colitis has been extensively studied. However, the specific effects of its microbial metabolites on gut barrier function remain unclear. Hence, we compared the protective effects of RES and its microbial metabolites dihydroresveratrol (DHR) and 3-(4-hydroxyphenyl)-propionic acid (4HPP) against intestinal barrier injury and colitis. Only 4HPP and RES significantly reduced paracellular permeability and the secretion of proinflammatory cytokines in lipopolysaccharides (LPS)-treated intestinal Caco-2 cells, which was consistent with the upregulation in tight junction (TJ) proteins. Furthermore, RES and 4HPP ameliorated intestinal barrier dysfunction and colonic inflammation in colitis mice, while DHR did not. In particular, the expressions of intestinal TJ proteins and Muc2 were restored by RES and 4HPP. The molecular mechanism involved the adenosine monophosphate-activated protein kinase (AMPK)-mediated activation of CDX2 and the regulation of the SIRT1/NF-κB pathway. These findings provide new insights into understanding the protective effects of RES against intestinal barrier damage and colitis.

Dietary EVOO Polyphenols and Gut Microbiota Interaction: Are There Any Sex/Gender Influences?

Accumulating evidence indicates that regular consumption of extra virgin olive oil (EVOO), the main source of fat in the Mediterranean diet, is associated with beneficial health effects and a reduced risk of developing chronic degenerative disorders. The beneficial effects of EVOO can be attributed to its unique composition in monounsaturated fats and phenolic compounds that provide important antioxidant, anti-inflammatory, and immune-modulating activities. On the other hand, it is well known that the gut microbiota has several important roles in normal human physiology, and its composition can be influenced by a multitude of environmental and lifestyle factors, among which dietary components play a relevant role. In the last few years, the two-way interaction between polyphenols, including those in EVOO, and the gut microbiota, i.e., the modulation of the microbiota by polyphenols and that of polyphenol metabolism and bioavailability by the microbiota, has attracted growing attention, being potentially relevant to explain the final effects of polyphenols, as well as of the microbiota profile. Furthermore, sex and gender can affect dietary habits, polyphenol intake, and nutrient metabolism. Lastly, it has been recently suggested that differences in gut microbiota composition could be involved in the unequal incidence of metabolic diseases observed between women and men, due to sex-dependent effects on shaping gut microbiota profiles according to diet. This review summarizes the most recent studies on the relationship between EVOO polyphenols and the gut microbiota, taking into account possible influences of sex and gender in modulating such an interaction.

Lunularin Producers versus Non-producers: Novel Human Metabotypes Associated with the Metabolism of Resveratrol by the Gut Microbiota

We describe here for the first time the consistent observation of two metabotypes associated with resveratrol metabolism by the human gut microbiota, that is, lunularin (LUNU)-producers and LUNU non-producers. In healthy volunteers (n = 195), resveratrol was reduced to dihydroresveratrol, which only in the LUNU-producer metabotype was sequentially dehydroxylated at the 5-position to yield LUNU and the 3-position to produce 4-hydroxydibenzyl. These metabolites (also 3,4'-dihydroxy-trans-stilbene in some LUNU-producers) were detected in the urine and (or) feces of 74% of volunteers after consuming resveratrol, while 26% lacked these dehydroxylase activities. The LUNU non-producer metabotype was more prevalent in females (P < 0.05) but independent of individuals' BMI and age. A 4-styrylphenol reductase in both metabotypes converted stilbenes to their corresponding dibenzyls, while no 4-dehydroxylation in stilbenes or dibenzyls was observed. 4-Hydroxy-trans-stilbene, pinosylvin, dihydropinosylvin, 3-hydroxydibenzyl, and 3-hydroxy-trans-stilbene were not detected in vivo or in vitro. Further research on LUNU metabotypes, their associated gut microbiota, and their impact on health is worthwhile.

Polyphenol Mechanisms against Gastric Cancer and Their Interactions with Gut Microbiota: A Review

The lack of new drugs and resistance to existing drugs are serious problems in gastric cancer(GC) treatment. The research found polyphenols possess anti-Helicobacter pylori(Hp) and antitumor activities and may be used in the research and development of drugs for cancer prevention and treatment. However, polyphenols are affected by their chemical structures and physical properties, which leads to relatively low bioavailability and bioactivity in vivo. The intestinal flora can improve the absorption, utilization, and biological activity of polyphenols, whereas polyphenol compounds can increase the richness of the intestinal flora, reduce the activity of carcinogenic bacteria, stabilize the proportion of core flora, and maintain homeostasis of the intestinal microenvironment. Our review summarizes the gastrointestinal flora-mediated mechanisms of polyphenol against GC.

Combinatory Exposure to Urolithin A, Alternariol, and Deoxynivalenol Affects Colon Cancer Metabolism and Epithelial Barrier Integrity in vitro

The human gastrointestinal tract is an important site of nutrient absorption and a crucial barrier against xenobiotics. It regularly faces “chemical cocktails” composed of food constituents, their human and microbial metabolites, and foodborne contaminants, such as mycotoxins. Hence, the colonic epithelium adapts to dietary molecules tuning its immune response, structural integrity, and metabolism to maintain intestinal homeostasis. While gut microbiota metabolites of berry ellagitannins, such as urolithin A (Uro A) might contribute to physiological epithelial barrier integrity, foodborne co-contaminating mycotoxins like alternariol (AOH) and deoxynivalenol (DON) could hamper epithelial function. Hence, we investigated the response of differentiated Caco-2 cells (clone C2BBe1) in vitro to the three compounds alone or in binary mixtures. In virtue of the possible interactions of Uro A, AOH, and DON with the aryl hydrocarbon receptor (AhR) pathway, potential effects on phase-I-metabolism enzymes and epithelial structural integrity were taken as endpoints for the evaluation. Finally, Liquid chromatography tandem mass spectrometry measurements elucidated the absorption, secretion, and metabolic capacity of the cells under single and combinatory exposure scenarios. Uro A and AOH as single compounds, and as a binary mixture, were capable to induce CYP1A1/1A2/1B1 enzymes triggered by the AhR pathway. In light of its ribosome inhibiting capacity, the trichothecene suppressed the effects of both dibenzo-α-pyrones. In turn, cellular responsiveness to Uro A and AOH could be sustained when co-exposed to DON-3-sulfate, instead of DON. Colonic epithelial structural integrity was rather maintained after incubation with Uro A and AOH: this was reinforced in the combinatory exposure scenario and disrupted by DON, an effect, opposed in combination. Passage through the cells as well as the metabolism of Uro A and AOH were rather influenced by co-exposure to DON, than by interaction with each other. Therefore, we conclude that although single foodborne bioactive substances individually could either support or disrupt the epithelial structure and metabolic capacity of colon cancer, exposure to chemical mixtures changes the experimental outcome and calls for the need of combinatory investigations for proper risk assessment.