Colonic bacterial metabolites and human health. Curr Opin Microbiol. 2013;16:246-254. [PMID: 23880135 DOI: 10.1016/j.mib.2013.07.002]

Dysbiosis of gut microbiota in promoting the development of colorectal cancer

Gastrointestinal microbiome, containing at least 100 trillion bacteria, resides in the mucosal surface of human intestine. Recent studies show that perturbations in the microbiota may influence physiology and link to a number of diseases, including colon tumorigenesis. Colorectal cancer (CRC), the third most common cancer, is the disease resulting from multi-genes and multi-factors, but the mechanistic details between gut microenvironment and CRC remain poorly characterized. Thanks to new technologies such as metagenome sequencing, progress in large-scale analysis of the genetic and metabolic profile of gut microbial has been possible, which has facilitated studies about microbiota composition, taxonomic alterations and host interactions. Different bacterial species and their metabolites play critical roles in the development of CRC. Also, microbiota is important in the inflammatory response and immune processes deregulation during the development and progression of CRC. This review summarizes current studies regarding the association between gastrointestinal microbiota and the development of CRC, which provides insights into the therapeutic strategy of CRC.

Mutual Interaction of Phenolic Compounds and Microbiota: Metabolism of Complex Phenolic Apigenin-C- and Kaempferol-O-Derivatives by Human Fecal Samples

Human colonic bacteria have an important impact on the biotransformation of flavonoid glycosides and their conversion can result in the formation of bioactive compounds. However, information about the microbial conversion of complex glycosylated flavonoids and the impact on the gut microbiota are still limited. In this study, in vitro fermentations with selected flavonoid O- and C-glycosides and three different fecal samples were performed. As a result, all flavonoid glycosides were metabolized via their aglycones yielding smaller substances. Main metabolites were 3-(4-hydroxyphenyl)propionic acid, 3-phenylpropionic acid, and phenylacetic acid. Differences in the metabolite formation due to different time courses between the donors were determined. Therefore, from all fermentations, the ones with a specific donor were always slower resulting in a lower number of metabolites compared to the others. For example, tiliroside was totally degraded from 0 h (105 ± 13.2 μM) within the first 24 h, while in the fermentations with fecal samples from other donors, tiliroside (107 ± 52.7 μM at 0 h) was not detected after 7 h anymore. In general, fermentation rates of C-glycosides were slower compared to the fermentation rates of O-glycosides. The O-glycoside tiliroside was degraded within 4 h while the gut microbiota converted the C-glycoside vitexin within 13 h. However, significant changes (p < 0.05) in the microbiota composition and short chain fatty acid levels as products of carbohydrate fermentation were not detected between incubations with different phenolic compounds. Therefore, microbiota diversity was not affected and a significant prebiotic effect of phenolic compounds cannot be assigned to flavonoid glycosides in food-relevant concentrations.

Hypoxia-induced transcription factor signaling is essential for larval growth of the mosquito Aedes aegypti

Gut microbes positively affect the physiology of many animals, but the molecular mechanisms underlying these benefits remain poorly understood. We recently reported that bacteria-induced gut hypoxia functions as a signal for growth and molting of the mosquito Aedes aegypti In this study, we tested the hypothesis that transduction of a gut hypoxia signal requires hypoxia-induced transcription factors (HIFs). Expression studies showed that HIF-α was stabilized in larvae containing bacteria that induce gut hypoxia but was destabilized in larvae that exhibit normoxia. However, we could rescue growth of larvae exhibiting gut normoxia by treating them with a prolyl hydroxylase inhibitor, FG-4592, that stabilized HIF-α, and inhibit growth of larvae exhibiting gut hypoxia by treating them with an inhibitor, PX-478, that destabilized HIF-α. Using these tools, we determined that HIF signaling activated the insulin/insulin growth factor pathway plus select mitogen-activated kinases and inhibited the adenosine monophosphate-activated protein kinase pathway. HIF signaling was also required for growth of the larval midgut and storage of neutral lipids by the fat body. Altogether, our results indicate that gut hypoxia and HIF signaling activate multiple processes in A. aegypti larvae, with conserved functions in growth and metabolism.

In vitro fermentation of gum acacia - impact on the faecal microbiota

Interest in the consumption of gum acacia (GA) has been associated with beneficial health effects, which may be mediated in part by prebiotic activity. Two doses of GA and fructooligosaccharide (FOS) (1 and 2%) were tested for their efficacy over 48 h in pH- and temperature-controlled anaerobic batch cultures inoculated with human faeces. Samples were taken after 0, 5, 10, 24 and 48 h of fermentation. The selective effects of GA (increases in Bifidobacterium spp. and Lactobacillus spp.) were similar to those of the known prebiotic FOS. The 1% dose of substrates showed more enhanced selectivity compared to the 2% dose. The fermentation of GA also led to SCFA production, specifically increased acetate after 10, 24 and 48 h of fermentation, propionate after 48 h and butyrate after 24 and 48 h. In addition, FOS led to significant increase in the main SCFAs. These results suggest that GA displays potential prebiotic properties.

The human microbiome and metabolomics: Current concepts and applications

The mammalian gastrointestinal tract has co-developed with a large number of microbes in a symbiotic relationship over millions of years. Recent studies indicate that indigenous bacteria are intimate with the intestine and play essential roles in health and disease. In the quest to maintain a stable niche, these prokaryotes influence multiple host metabolic pathways, resulting from an interactive host-microbiota metabolic signaling and impacting strongly on the metabolic phenotypes of the host. Since dysbiosis of the gut bacteria result in alteration in the levels of certain microbial and host co-metabolites, identifying these markers could enhance early detection of diseases. Also, identification of these metabolic fingerprints could give us clues as to how to manipulate the microbiome to promote health or treat diseases. This review provides an overview of our current knowledge of the microbiome and metablomics, applications and the future perspectives.

Landscape of the regulatory elements for lysine 2-hydroxyisobutyrylation pathway

Short-chain fatty acids and their corresponding acyl-CoAs sit at the crossroads of metabolic pathways and play important roles in diverse cellular processes. They are also precursors for protein post-translational lysine acylation modifications. A noteworthy example is the newly identified lysine 2-hydroxyisobutyrylation (Khib) that is derived from 2-hydroxyisobutyrate and 2-hydroxyisobutyryl-CoA. Histone Khib has been shown to be associated with active gene expression in spermatogenic cells. However, the key elements that regulate this post-translational lysine acylation pathway remain unknown. This has hindered characterization of the mechanisms by which this modification exerts its biological functions. Here we show that Esa1p in budding yeast and its homologue Tip60 in human could add Khib to substrate proteins both in vitro and in vivo. In addition, we have identified HDAC2 and HDAC3 as the major enzymes to remove Khib. Moreover, we report the first global profiling of Khib proteome in mammalian cells, identifying 6 548 Khib sites on 1 725 substrate proteins. Our study has thus discovered both the "writers" and "erasers" for histone Khib marks, and major Khib protein substrates. These results not only illustrate the landscape of this new lysine acylation pathway, but also open new avenues for studying diverse functions of cellular metabolites associated with this pathway.

The Influence of Gut Microbial Metabolism on the Development and Progression of Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is defined as the presence of excess fat in the liver parenchyma in the absence of excess alcohol consumption and overt inflammation. It has also been described as the hepatic manifestation of metabolic syndrome (Than NN, Newsome PN, Atherosclerosis. 239:192-202, 2015). The incidence of NAFLD has been reported to be 43-60% in diabetics, ~90% in patients with hyperlipidemia and 91% in morbidly obese patients (Than NN, Newsome PN, Atherosclerosis. 239:192-202, 2015, Machado M, Marques-Vidal P, Cortez-Pinto H, J Hepatol, 45:600-606, 2006, Vernon G, Baranova A, Younossi ZM, Aliment Pharmacol Ther, 34:274-285, 2011). The risk factors that have been associated with the development of NAFLD include male gender, increasing age, obesity, insulin resistance, diabetes and hyperlipidemia (Attar BM, Van Thiel DH, Sci World J, 2013:481893, 2013, Gaggini M, Morelli M, Buzzigoli E, DeFronzo RA, Bugianesi E, Gastaldelli A, Forum Nutr, 5:1544-1460, 2013). All of these risk factors have been linked to alterations of the gut microbiota, ie., gut dysbiosis (He X, Ji G, Jia W, Li H, Int J Mol Sci, 17:300, 2016). However, it must be pointed out that the prevalence of NAFLD in normal weight individuals without metabolic risk factors is ~16% (Than NN, Newsome PN, Atherosclerosis. 239:192-202, 2015). This fact has led some investigators to hypothesize that the gut microbiota can impact lipid metabolism in the liver independently of obesity-related metabolic factors (Marchesi JR, Adams DH, Fava F, Hermes GD, Hirschfield GM, Hold g, et al., Gut, 65:330 339, 2016) (Le Roy T, Llopis M, Lepage P, Bruneau A, Rabot S, Bevilacqua C, et al., Gut, 62:1787-1794, 2013). In this chapter, we will explore the effect of the gut microbiota on hepatic lipid metabolism and how this affects the development of NAFLD.

Evaluation of markers out of the steroid profile for the screening of testosterone misuse. Part II: Intramuscular administration

In the fight against doping, the introduction of alternative markers to the steroid profile can be considered as an effective approach to improve the screening capabilities for the detection of testosterone (T) misuse. The aim of this study was to evaluate the potential of several T metabolites (cysteinyl conjugated and glucuronoconjugated resistant to enzymatic hydrolysis) to detect both the transdermal and the intramuscular administration of T. In Part I of the study, we studied the potential of these metabolites for the detection of T transdermal administration. Results revealed that resistant glucuronides can be a suitable complement to the current steroid profile. In this, Part II, dedicated to the intramuscular administration, we studied the potential of cysteinyl conjugated, resistant glucuronoconjugated and 1-cyclopentenoylglycine (1-CPG) for the detection of a single intramuscular injection of T cypionate. Possible differences in the excretion profile of all markers were explored between individuals with low basal (n=6) and medium basal (n=6) values of the testosterone/epitestosterone ratio (T/E). The results showed that all tested markers presented low intra-individual stability in basal conditions. Despite this, all glucuronoconjugated markers and 1-CPG, but not the cysteinyl conjugated markers, provided detection windows that were similar or longer than those obtained by markers currently included in the steroid profile. Based on the results obtained from the 2 parts of this study and from previously reported data, the potential applicability and the limitations of including these markers in the steroid profile are discussed.

Gut microbiome response to short-term dietary interventions in reactive hypoglycemia subjects

BACKGROUND

Reactive hypoglycemia is a metabolic disorder that provokes severe hypoglycemic episodes after meals. Over recent years, the gut microbiota has been recognized as potential target for the control of metabolic diseases, and the possibility to correct gut microbiota dysbioses through diet, favouring the recovery of metabolic homeostasis, has been considered.

METHODS

We investigate the impact of 2 short-term (3-day) nutritional interventions, based on the macrobiotic Ma-Pi 2 diet and a control Mediterranean diet, on the structure and functionality of the gut microbiota in 12 patients affected by reactive hypoglycemia. The gut microbiota composition was characterized by next-generation sequencing of the V3 to V4 region of the 16S rRNA gene, and the ecosystem functionality was addressed by measuring the faecal concentration of short-chain fatty acids (SCFAs). In order to measure the short-term physiological gut microbiota fluctuation, the microbiomes of 7 healthy people were characterized before and after 3 days of constant diet.

RESULTS

While no convergence of the gut microbiota compositional profiles was observed, a significant increase in SCFA faecal levels was induced only in the Ma-Pi 2 diet group, suggesting the potential of this diet to support a short-term functional convergence of the gut microbiota, regardless of the individual compositional layout.

CONCLUSIONS

The Ma-Pi 2 diet, with its high fibre load, was effective in increasing the production of SCFAs by the gut microbiota. Because these metabolites are known for their ability to counterbalance the metabolic deregulation in persons with glucose impairment disorders, their increased bioavailability could be of some relevance in reactive hypoglycemia.

Do bacteria shape our development? Crosstalk between intestinal microbiota and HPA axis

The human body contains as many bacteria in the intestine as the total number of human body cells. These bacteria have a central position in human health and disease, and would also play a role in the regulation of emotions, behavior, and even higher cognitive functions. The Hypothalamic-Pituitary-Adrenal axis (HPA axis) is a major physiological stress system that produces cortisol. This hormone is involved in responding to environmental stress and also shapes many aspects of brain development. Both the HPA axis and the intestinal microbiota show rapid and profound developmental changes during the first years of life. Early environmental disturbances can affect the development of both systems. Early adversity, for example, is known to lead to later unbalances in both, as well as to psychopathological behavior and emotions. The goal of this theoretical review is to summarize current knowledge on the developmental crosstalk between the intestinal microbiota and the HPA axis, providing a basis for understanding the development and bidirectional communication between these two essential systems in human functioning.

An In Vitro Fermentation Study on the Effects of Gluten FriendlyTM Bread on Microbiota and Short Chain Fatty Acids of Fecal Samples from Healthy and Celiac Subjects

Recently, an innovative gluten detoxification method called Gluten Friendly^TM (GF) has been developed. It induces structural modifications, which abolish the antigenic capacity of gluten and reduce the in vitro immunogenicity of the most common epitopes involved in celiac disease, without compromising the nutritional and technological properties. This study investigated the in vitro effects of GF bread (GFB) on the fecal microbiota from healthy and celiac individuals by a three-stage continuous fermentative system, which simulates the colon (vessel 1, proximal colon; vessel 2, transverse colon; and vessel 3, distal colon), as well as on the production of short chain fatty acids (SCFA, acetate, propionate, butyrate). The system was fed with GFB and the changes in microbiota through fluorescence in situ hybridization and in SCFA content were assessed. GFB exerted beneficial modulations such as bifidogenic effects in each compartment of the model both with healthy- and celiac-derived samples, as well as growth in Clostridium clusters XIVa+b in celiac-derived samples. Furthermore, increased levels of acetic acid were found in vessel 1 inoculated with the fecal microbiota of healthy individuals, as well as acetic and propionic in vessel 1 and 2 with celiac-derived samples. In addition, the use of multivariate approaches showed that the supplementation of GFB could result in a different modulation of the fecal microbiota and SCFA, as a function of initial equilibrium.

Beneficial microbial signals from alternative feed ingredients: a way to improve sustainability of broiler production?

More sustainable broiler meat production can be facilitated by the increased use of cheap by‐products and local crops as feed ingredients, while not affecting animal performance and intestinal health, or even improving intestinal health, so that antibiotic usage is further reduced. To achieve this, knowledge of the relationship between the taxonomic and functional microbiota composition and intestinal health is required. In addition, the relationship between the novel feed sources, the substrates present in these feed sources, and the breakdown by enzymes and microbial networks can be crucial, because this can form the basis for development of tailored feed‐type specific solutions for optimal digestion and animal performance.

An in vitro evaluation of the effects of a Yucca schidigera extract and chestnut tannins on composition and metabolic profiles of canine and feline faecal microbiota

The in vitro effect of a Yucca schidigera extract (YSE) and tannins from chestnut wood on composition and metabolic activity of canine and feline faecal microbiota was evaluated. Four treatments were carried out: control diet, chestnut tannins (CT), YSE and CT + YSE. The YSE was added to canine and feline faecal cultures at 0.1 g/l, while CT were added at 0.3 g/l for a 24-h incubation. A total of 130 volatile compounds were detected by means of headspace-solid phase microextraction gas-chromatography/mass spectrometry analyses. Several changes in the metabolite profiles of fermentation fluids were found, including a decrease of alcohols (-19%) and esters (-42%) in feline and canine inoculum, respectively, which was due to the antibacterial properties of tannins. In canine inoculum, after 6 h, YSE + CT caused lower cadaverine concentrations (-37%), while ammonia (-4%) and quinolone (-27%) were reduced by addition of CT. After 24 h, the presence of CT resulted in a decrease of sulphur compounds, such as dimethyl sulphide (-69%) and dimethyl disulphide (-20%). In feline faecal cultures, after 6 h, CT lowered the amount of indole (-48%), whereas YSE tended to decrease trimethylamine levels (-16%). Both in canine and feline inoculum, addition of CT and, to a minor extent, YSE affected volatile fatty acids patterns. In canine faecal cultures, CT exerted a marginal inhibitory effect on Escherichia coli population (-0.45 log 10 numbers of DNA copies/ml), while enterococci were increased (+2.06 log 10 numbers of DNA copies/ml) by YSE. The results from the present study show that YSE and tannins from chestnut wood exert different effects on the composition and metabolism of canine and feline faecal microbiota. In particular, the supplementation of YSE and tannins to diets for dogs and cats may be beneficial due to the reduction of the presence of some potentially toxic volatile metabolites in the animals' intestine.

Prion disease pathogenesis in the absence of the commensal microbiota

Prion diseases are a unique group of transmissible, typically sub-acute, neurodegenerative disorders. During central nervous system (CNS) prion disease, the microglia become activated and are thought to provide a protective response by scavenging and clearing prions. The mammalian intestine is host to a large burden of commensal micro-organisms, especially bacteria, termed the microbiota. The commensal microbiota has beneficial effects on host health, including through the metabolism of essential nutrients, regulation of host development and protection against pathogens. The commensal gut microbiota also constitutively regulates the functional maturation of microglia in the CNS, and microglial function is impaired when it is absent in germ-free mice. In the current study, we determined whether the absence of the commensal gut microbiota might also affect prion disease pathogenesis. Our data clearly show that the absence of the commensal microbiota in germ-free mice did not affect prion disease duration or susceptibility after exposure to prions by intraperitoneal or intracerebral injection. Furthermore, the magnitude and distribution of the characteristic neuropathological hallmarks of terminal prion disease in the CNS, including the development of spongiform pathology, accumulation of prion disease-specific protein (PrP), astrogliosis and microglial activation, were similar in conventionally housed and germ-free mice. Thus, although the commensal gut microbiota constitutively promotes the maintenance of the microglia in the CNS under steady-state conditions in naïve mice, our data suggest that dramatic changes to the abundance or complexity of the commensal gut microbiota are unlikely to influence CNS prion disease pathogenesis.

Metabolomics and Cardiology: Toward the Path of Perinatal Programming and Personalized Medicine

Heart diseases are one of the leading causes of death in Western Countries and tend to become chronic, lowering the quality of life of the patients and ending up in a massive cost for the Health Systems and the society. Thus, there is a growing interest in finding new technologies that would allow the physician to effectively treat and prevent cardiac illnesses. Metabolomics is one of the new "omics" sciences enabling creation of a photograph of the metabolic state of an individual exposed to different environmental factors and pathologies. This review analyzed the most recent literature about this technology and its application in cardiology in order to understand the metabolic shifts that occur even before the manifestation of these pathologies to find possible early predictive biomarkers. In this way, it could be possible to find better treatments, ameliorate the patient's quality of life, and lower the death rate. This technology seems to be so promising that several industries are trying to set up kits to immediately assess the metabolites variations in order to provide a faster diagnosis and the best treatment specific for that patient, offering a further step toward the path of the development of a tailored medicine.

Fruit Fiber Consumption Specifically Improves Liver Health Status in Obese Subjects under Energy Restriction

The prevalence of non-alcoholic-fatty-liver-disease (NAFLD) is associated with obesity, diabetes, and metabolic syndrome (MS). This study aimed to evaluate the influence of two energy-restricted diets on non-invasive markers and scores of liver damage in obese individuals with features of MS after six months of follow-up and to assess the role of fiber content in metabolic outcomes. Seventy obese individuals from the RESMENA (Reduction of Metabolic Syndrome in Navarra) study were evaluated at baseline and after six months of energy-restricted nutritional intervention (American Heart Association (AHA) and RESMENA dietary groups). Dietary records, anthropometrical data, body composition by dual energy X-ray absorptiometry (DXA), and routine laboratory measurements were analyzed by standardized methods. Regarding liver status, cytokeratin-18 fragments and several non-invasive scores of fatty liver were also assessed. The RESMENA strategy was a good and complementary alternative to AHA for the treatment of obesity-related comorbidities. Participants with higher insoluble fiber consumption (≥7.5 g/day) showed improvements in fatty liver index (FLI), hepatic steatosis index (HIS), and NAFLD liver fat score (NAFLD_LFS), while gamma-glutamyl transferase (GGT) and transaminases evidenced significant improvements as a result of fruit fiber consumption (≥8.8 g/day). Remarkably, a regression model evidenced a relationship between liver status and fiber from fruits. These results support the design of dietary patterns based on the consumption of insoluble fiber and fiber from fruits in the context of energy restriction for the management of obese patients suffering fatty liver disease.

Berberine-induced bioactive metabolites of the gut microbiota improve energy metabolism

OBJECTIVE

Berberine (BBR) clinically lowers blood lipid and glucose levels via multi-target mechanisms. One of the possible mechanisms is related to its effect on the short chain fatty acids (SCFAs) of the gut microbiota. The goal of this study is to investigate the therapeutic effect and mode of action of BBR working through SCFAs of the gut microbiota (especially, butyrate).

METHODS

Gas chromatography (GC) was used to detect butyrate and other SCFAs chemically. The effect of BBR on butyrate production was investigated in vitro as well as in several animal systems. Microarrays were used to analyze the composition change in the intestinal bacteria community after treatment with BBR. BBR-induced change in the energy production and gene regulation of intestinal bacteria was examined in order to elucidate the underlying molecular mechanisms.

RESULTS

We show that oral administration of BBR in animals promoted the gut microbiota to produce butyrate, which then enters the blood and reduces blood lipid and glucose levels. Incubating gut bacterial strains in vitro with BBR increased butyrate production. Orally treating animals directly with butyrate reduced blood lipid and glucose levels through a mechanism different from that of BBR. Intraperitoneal BBR administration did not increase butyrate but reduced blood lipid and glucose levels, suggesting that BBR has two modes of action: the direct effect of the circulated BBR and the indirect effect working through butyrate of the gut microbiota. Pre-treating animals orally with antibiotics abolished the effect of BBR on butyrate. A mechanism study showed that BBR (given orally) modified mice intestinal bacterial composition by increasing the abundance of butyrate-producing bacteria. Furthermore, BBR suppressed bacterial ATP production and NADH levels, resulting in increased butyryl-CoA and, eventually, butyrate production via upregulating phosphotransbutyrylase/butyrate kinase and butyryl-CoA:acetate-CoA transferase in bacteria.

CONCLUSION

Promotion of butyrate (etc) production in gut microbiota might be one of the important mechanisms of BBR in regulating energy metabolism.

MicroRNAs at the epicenter of intestinal homeostasis

Maintaining intestinal homeostasis is a key prerequisite for a healthy gut. Recent evidence points out that microRNAs (miRNAs) act at the epicenter of the signaling networks regulating this process. The fine balance in the interaction between gut microbiota, intestinal epithelial cells, and the host immune system is achieved by constant transmission of signals and their precise regulation. Gut microbes extensively communicate with the host immune system and modulate host gene expression. On the other hand, sensing of gut microbiota by the immune cells provides appropriate tolerant responses that facilitate the symbiotic relationships. While the role of many regulatory proteins, receptors and their signaling pathways in the regulation of the intestinal homeostasis is well documented, the involvement of non-coding RNA molecules in this process has just emerged. This review discusses the most recent knowledge about the contribution of miRNAs in the regulation of the intestinal homeostasis.

Faecal microbiota of healthy adults in south India: Comparison of a tribal & a rural population

BACKGROUND & OBJECTIVES

The relevance of the gut microbiota to human health is increasingly appreciated. The objective of this study was to compare the gut microbiota of a group of adult tribals with that of healthy adult villagers in Tamil Nadu, India.

METHODS

Faeces were collected from 10 healthy tribal adults (TAs) in the Jawadhi hills and from 10 healthy villagers [rural adults (RAs)] in Vellore district, Tamil Nadu. DNA was extracted, and 456 bp segments comprising hypervariable regions 3 and 4 of the 16S rRNA gene were amplified, barcoded and 454 sequenced.

RESULTS

Totally 227,710 good-quality reads were analyzed. TAs consumed a millets-based diet, ate pork every day, and did not consume milk or milk products. RAs consumed a rice-based diet with meat intake once a week. In both groups, Firmicutes was the most abundant phylum, followed by Proteobacteria, Bacteroidetes and Actinobacteria. The median Firmicutes-to-Bacteroidetes ratio was 34.0 in TA and 92.9 in RA groups. Actinobacteria were significantly low in TA, possibly due to non-consumption of milk. Clostridium constituted the most abundant genus in both groups, but was significantly more abundant in TAs than RAs, while Streptococcus was significantly more abundant in RA (P<0.05). Analyses of genetic distance revealed that the microbiota were distinctly different between TA and RA, and principal component analysis using 550 distinct taxonomically identifiable sequences revealed a clear separation of microbiota composition in the two groups. Phylogenetic analysis of major microbiota indicated clustering of microbial groups at different major branch points for TAs and RAs.

INTERPRETATION & CONCLUSIONS

Phylum Firmicutes and genus Clostridium constituted the bulk of the faecal microbiota, while significant differences in composition between the groups were probably due to differences in diet and lifestyle.

Human gut microbiota: the links with dementia development

Dementia is a comprehensive category of brain diseases that is great enough to affect a person's daily functioning. The most common type of dementia is Alzheimer's disease, which makes most of cases. New researches indicate that gastrointestinal tract microbiota are directly linked to dementia pathogenesis through triggering metabolic diseases and low-grade inflammation progress. A novel strategy is proposed for the management of these disorders and as an adjuvant for psychiatric treatment of dementia and other related diseases through modulation of the microbiota (e.g. with the use of probiotics).

Health Benefits of Fiber Fermentation

Although fiber is well recognized for its effect on laxation, increasing evidence supports the role of fiber in the prevention and treatment of chronic disease. The aim of this review is to provide an overview of the health benefits of fiber and its fermentation, and describe how the products of fermentation may influence disease risk and treatment. Higher fiber intakes are associated with decreased risk of cardiovascular disease, type 2 diabetes, and some forms of cancer. Fiber may also have a role in lowering blood pressure and in preventing obesity by limiting weight gain. Fiber is effective in managing blood glucose in type 2 diabetes, useful for weight loss, and may provide therapeutic adjunctive roles in kidney and liver disease. In addition, higher fiber diets are not contraindicated in inflammatory bowel disease or irritable bowel syndrome and may provide some benefit. Common to the associations with disease reduction is fermentation of fiber and its potential to modulate microbiota and its activities and inflammation, specifically the production of anti-inflammatory short chain fatty acids, primarily from saccharolytic fermentation, versus the deleterious products of proteolytic activity. Because fiber intake is inversely associated with all-cause mortality, mechanisms by which fiber may reduce chronic disease risk and provide therapeutic benefit to those with chronic disease need further elucidation and large, randomized controlled trials are needed to confirm causality.Teaching Points• Strong evidence supports the association between higher fiber diets and reduced risk of cardiovascular disease, type 2 diabetes, and some forms of cancer.• Higher fiber intakes are associated with lower body weight and body mass index, and some types of fiber may facilitate weight loss.• Fiber is recommended as an adjunctive medical nutritional therapy for type 2 diabetes, chronic kidney disease, and certain liver diseases.• Fermentation and the resulting shifts in microbiota composition and its activity may be a common means by which fiber impacts disease risk and management.

The Role of the Gastrointestinal Microbiota in Visceral Pain

A growing body of preclinical and clinical evidence supports a relationship between the complexity and diversity of the microorganisms that inhabit our gut (human gastrointestinal microbiota) and health status. Under normal homeostatic conditions this microbial population helps maintain intestinal peristalsis, mucosal integrity, pH balance, immune priming and protection against invading pathogens. Furthermore, these microbes can influence centrally regulated emotional behaviour through mechanisms including microbially derived bioactive molecules (amino acid metabolites, short-chain fatty acids, neuropeptides and neurotransmitters), mucosal immune and enteroendocrine cell activation, as well as vagal nerve stimulation.The microbiota-gut-brain axis comprises a dynamic matrix of tissues and organs including the brain, autonomic nervous system, glands, gut, immune cells and gastrointestinal microbiota that communicate in a complex multidirectional manner to maintain homeostasis and resist perturbation to the system. Changes to the microbial environment, as a consequence of illness, stress or injury, can lead to a broad spectrum of physiological and behavioural effects locally including a decrease in gut barrier integrity, altered gut motility, inflammatory mediator release as well as nociceptive and distension receptor sensitisation. Centrally mediated events including hypothalamic-pituitary-adrenal (HPA) axis, neuroinflammatory events and neurotransmitter systems are concomitantly altered. Thus, both central and peripheral pathways associated with pain manifestation and perception are altered as a consequence of the microbiota-gut-brain axis imbalance.In this chapter the involvement of the gastrointestinal microbiota in visceral pain is reviewed. We focus on the anatomical and physiological nodes whereby microbiota may be mediating pain response, and address the potential for manipulating gastrointestinal microbiota as a therapeutic target for visceral pain.

Gut microbial metabolism defines host metabolism: an emerging perspective in obesity and allergic inflammation

The presence of >100 trillion microorganisms (collectively called gut microbiota) in our large intestine is essential for the maintenance of health. The gut microbiota starts to develop before birth and matures within first three years of life. The Western diet and lifestyle have been implicated in causing an imbalance of gut microbial communities and their metabolites that consequence in disease states, such as obesity and asthma. With more than 13% of the world population currently living with obesity and one out of 10 children diagnosed with asthma, we explore here the recent developments in the biosynthesis and mode of action of the key metabolites in relation to these two chronic inflammatory conditions.

Human gut microbiota: the links with dementia development

Dementia is a comprehensive category of brain diseases that is great enough to affect a person's daily functioning. The most common type of dementia is Alzheimer's disease, which makes most of cases. New researches indicate that gastrointestinal tract microbiota are directly linked to dementia pathogenesis through triggering metabolic diseases and low-grade inflammation progress. A novel strategy is proposed for the management of these disorders and as an adjuvant for psychiatric treatment of dementia and other related diseases through modulation of the microbiota (e.g. with the use of probiotics).

How to Manipulate the Microbiota: Prebiotics

During the last century, human nutrition has evolved from the definition of our nutritional needs and the identification of ways to meet them, to the identification of food components that can optimise our physiological and psychological functions. This development, which aims to ensure the welfare, health and reduced susceptibility to disease during life, gave birth to the concept of "functional foods". In this context, there is an increasing interest in the physiological effects induced by the dense and diverse microbiota which inhabits the human colon and whose development depends on the fermentation of undigested food residues. Thus, much research aims at identifying ways to guide these impacts in order to benefit the health of the host. It is in this context that the concept of "prebiotics" was developed in the 1990s. Since then, prebiotics have stimulated extensive work in order to clarify their definition, their nature and their physiological properties in accordance with the evolution of knowledge on the intestinal microbiota. However many questions remain open about their specificities, their mechanism(s) of action and therefore the relevance of their current categorisation.

Cognitive impairment by antibiotic-induced gut dysbiosis: Analysis of gut microbiota-brain communication

Emerging evidence indicates that disruption of the gut microbial community (dysbiosis) impairs mental health. Germ-free mice and antibiotic-induced gut dysbiosis are two approaches to establish causality in gut microbiota-brain relationships. However, both models have limitations, as germ-free mice display alterations in blood-brain barrier and brain ultrastructure and antibiotics may act directly on the brain. We hypothesized that the concerns related to antibiotic-induced gut dysbiosis can only adequately be addressed if the effect of intragastric treatment of adult mice with multiple antibiotics on (i) gut microbial community, (ii) metabolite profile in the colon, (iii) circulating metabolites, (iv) expression of neuronal signaling molecules in distinct brain areas and (v) cognitive behavior is systematically investigated. Of the antibiotics used (ampicillin, bacitracin, meropenem, neomycin, vancomycin), ampicillin had some oral bioavailability but did not enter the brain. 16S rDNA sequencing confirmed antibiotic-induced microbial community disruption, and metabolomics revealed that gut dysbiosis was associated with depletion of bacteria-derived metabolites in the colon and alterations of lipid species and converted microbe-derived molecules in the plasma. Importantly, novel object recognition, but not spatial, memory was impaired in antibiotic-treated mice. This cognitive deficit was associated with brain region-specific changes in the expression of cognition-relevant signaling molecules, notably brain-derived neurotrophic factor, N-methyl-d-aspartate receptor subunit 2B, serotonin transporter and neuropeptide Y system. We conclude that circulating metabolites and the cerebral neuropeptide Y system play an important role in the cognitive impairment and dysregulation of cerebral signaling molecules due to antibiotic-induced gut dysbiosis.

The influence of the commensal and pathogenic gut microbiota on prion disease pathogenesis

Prion diseases are a unique group of transmissible, chronic, neurodegenerative disorders. Following peripheral exposure (e.g. oral), prions often accumulate first within the secondary lymphoid tissues before they infect the central nervous system (CNS). Prion replication within secondary lymphoid tissues is crucial for the efficient spread of disease to the CNS. Once within the CNS, the responses of innate immune cells within it can have a significant influence on neurodegeneration and disease progression. Recently, there have been substantial advances in our understanding of how cross-talk between the host and the vast community of commensal microorganisms present at barrier surfaces such as the gut influences the development and regulation of the host's immune system. These effects are evident not only in the mucosal immune system in the gut, but also in the CNS. The actions of this microbial community (the microbiota) have many important beneficial effects on host health, from metabolism of nutrients and regulation of host development to protection from pathogen infection. However, the microbiota can also have detrimental effects in some circumstances. In this review we discuss the many and varied interactions between prions, the host and the gut microbiota. Particular emphasis is given to the ways by which changes to the composition of the commensal gut microbiota or congruent pathogen infection may influence prion disease pathogenesis and/or disease susceptibility. Understanding how these factors influence prion pathogenesis and disease susceptibility is important for assessing the risk to infection and the design of novel opportunities for therapeutic intervention.

The microbial-mammalian metabolic axis: a critical symbiotic relationship

PURPOSE OF REVIEW

The microbial-mammalian symbiosis plays a critical role in metabolic health. Microbial metabolites emerge as key messengers in the complex communication between the gut microbiota and their host. These chemical signals are mainly derived from nutritional precursors, which in turn are also able to modify gut microbiota population. Recent advances in the characterization of the gut microbiome and the mechanisms involved in this symbiosis allow the development of nutritional interventions. This review covers the latest findings on the microbial-mammalian metabolic axis as a critical symbiotic relationship particularly relevant to clinical nutrition.

RECENT FINDINGS

The modulation of host metabolism by metabolites derived from the gut microbiota highlights the importance of gut microbiota in disease prevention and causation. The composition of microbial populations in our gut ecosystem is a critical pathophysiological factor, mainly regulated by diet, but also by the host's characteristics (e.g. genetics, circadian clock, immune system, age). Tailored interventions, including dietary changes, the use of antibiotics, prebiotic and probiotic supplementation and faecal transplantation are promising strategies to manipulate microbial ecology.

SUMMARY

The microbiome is now considered as an easily reachable target to prevent and treat related diseases. Recent findings in both mechanisms of its interactions with host metabolism and in strategies to modify gut microbiota will allow us to develop more effective treatments especially in metabolic diseases.

Xenobiotics: Interaction with the Intestinal Microflora

The human body is host to 100 trillion gut microbes, approximately 10-times more than all human cells. It is estimated that the approximately 500-1000 species residing in the human gut encode 150-fold more unique genes than the human genome. The gut microbiota has important functions in metabolic processing, such as energy production, immune cell development, food digestion, and epithelial homeostasis. It has been increasingly recognized that a dysregulated gut microbiome contributes in a significant way to a variety of diseases, including diabetes, obesity, cardiovascular diseases, allergies, and inflammatory bowel disease. In particular, accumulating evidence indicates that functional interactions between the gut microbiome and xenobiotics play a role in mediating chemical toxicity and causing or exacerbating human disease. This review summarizes emerging evidence that illustrates how xenobiotics can affect the gut microbiome structure, create functional changes to the gut microbiome, and become biotransformed by the gut microbiome.

Modulation of gut microbiota dysbioses in type 2 diabetic patients by macrobiotic Ma-Pi 2 diet

The gut microbiota exerts a role in type 2 diabetes (T2D), and deviations from a mutualistic ecosystem layout are considered a key environmental factor contributing to the disease. Thus, the possibility of improving metabolic control in T2D by correcting gut microbiome dysbioses through diet has been evaluated. Here, we explore the potential of two different energy-restricted dietary approaches - the fibre-rich macrobiotic Ma-Pi 2 diet or a control diet recommended by Italian professional societies for T2D treatment - to correct gut microbiota dysbioses in T2D patients. In a previous 21-d open-label MADIAB trial, fifty-six overweight T2D patients were randomised to the Ma-Pi 2 or the control diet. For the present study, stools were collected before and after intervention from a subset of forty MADIAB participants, allowing us to characterise the gut microbiota by 16S rRNA sequencing and imputed metagenomics. To highlight microbiota dysbioses in T2D, the gut microbiota of thirteen normal-weight healthy controls were characterised. According to our findings, both diets were effective in modulating gut microbiome dysbioses in T2D, resulting in an increase of the ecosystem diversity and supporting the recovery of a balanced community of health-promoting SCFA producers, such as Faecalibacterium, Roseburia, Lachnospira, Bacteroides and Akkermansia. The Ma-Pi 2 diet, but not the control diet, was also effective in counteracting the increase of possible pro-inflammatory groups, such as Collinsella and Streptococcus, in the gut ecosystem, showing the potential to reverse pro-inflammatory dysbioses in T2D, and possibly explaining the greater efficacy in improving the metabolic control.

Impact of the gut microbiota on inflammation, obesity, and metabolic disease

The human gut harbors more than 100 trillion microbial cells, which have an essential role in human metabolic regulation via their symbiotic interactions with the host. Altered gut microbial ecosystems have been associated with increased metabolic and immune disorders in animals and humans. Molecular interactions linking the gut microbiota with host energy metabolism, lipid accumulation, and immunity have also been identified. However, the exact mechanisms that link specific variations in the composition of the gut microbiota with the development of obesity and metabolic diseases in humans remain obscure owing to the complex etiology of these pathologies. In this review, we discuss current knowledge about the mechanistic interactions between the gut microbiota, host energy metabolism, and the host immune system in the context of obesity and metabolic disease, with a focus on the importance of the axis that links gut microbes and host metabolic inflammation. Finally, we discuss therapeutic approaches aimed at reshaping the gut microbial ecosystem to regulate obesity and related pathologies, as well as the challenges that remain in this area.

The microbiome: A key regulator of stress and neuroinflammation

There is a growing emphasis on the relationship between the complexity and diversity of the microorganisms that inhabit our gut (human gastrointestinal microbiota) and health/disease, including brain health and disorders of the central nervous system. The microbiota-gut-brain axis is a dynamic matrix of tissues and organs including the brain, glands, gut, immune cells and gastrointestinal microbiota that communicate in a complex multidirectional manner to maintain homeostasis. Changes in this environment can lead to a broad spectrum of physiological and behavioural effects including hypothalamic-pituitary-adrenal (HPA) axis activation, and altered activity of neurotransmitter systems and immune function. While an appropriate, co-ordinated physiological response, such as an immune or stress response are necessary for survival, a dysfunctional response can be detrimental to the host contributing to the development of a number of CNS disorders. In this review, the involvement of the gastrointestinal microbiota in stress-mediated and immune-mediated modulation of neuroendocrine, immune and neurotransmitter systems and the consequential behaviour is considered. We also focus on the mechanisms by which commensal gut microbiota can regulate neuroinflammation and further aim to exploit our understanding of their role in stress-related disorders as a consequence of neuroinflammatory processes.

Akkermansia muciniphila and improved metabolic health during a dietary intervention in obesity: relationship with gut microbiome richness and ecology

OBJECTIVE

Individuals with obesity and type 2 diabetes differ from lean and healthy individuals in their abundance of certain gut microbial species and microbial gene richness. Abundance of Akkermansia muciniphila, a mucin-degrading bacterium, has been inversely associated with body fat mass and glucose intolerance in mice, but more evidence is needed in humans. The impact of diet and weight loss on this bacterial species is unknown. Our objective was to evaluate the association between faecal A. muciniphila abundance, faecal microbiome gene richness, diet, host characteristics, and their changes after calorie restriction (CR).

DESIGN

The intervention consisted of a 6-week CR period followed by a 6-week weight stabilisation diet in overweight and obese adults (N=49, including 41 women). Faecal A. muciniphila abundance, faecal microbial gene richness, diet and bioclinical parameters were measured at baseline and after CR and weight stabilisation.

RESULTS

At baseline A. muciniphila was inversely related to fasting glucose, waist-to-hip ratio and subcutaneous adipocyte diameter. Subjects with higher gene richness and A. muciniphila abundance exhibited the healthiest metabolic status, particularly in fasting plasma glucose, plasma triglycerides and body fat distribution. Individuals with higher baseline A. muciniphila displayed greater improvement in insulin sensitivity markers and other clinical parameters after CR. These participants also experienced a reduction in A. muciniphila abundance, but it remained significantly higher than in individuals with lower baseline abundance. A. muciniphila was associated with microbial species known to be related to health.

CONCLUSIONS

A. muciniphila is associated with a healthier metabolic status and better clinical outcomes after CR in overweight/obese adults. The interaction between gut microbiota ecology and A. muciniphila warrants further investigation.

TRIAL REGISTRATION NUMBER

NCT01314690.

Fiber content of diet affects exhaled breath volatiles in fasting and postprandial state in a pilot crossover study

Our pilot study examined the potential of exhaled breath analysis in studying the metabolic effects of dietary fiber (DF). We hypothesized that a high-fiber diet (HFD) containing whole grain rye changes volatile organic compound (VOC) levels in exhaled breath and that consuming a single meal affects these levels. Seven healthy men followed a week-long low-fiber diet (17 g/d) and HFD (44 g/d) in a randomized crossover design. A test meal containing 50 g of the available carbohydrates from wheat bread was served as breakfast after each week. Alveolar exhaled breath samples were analyzed at fasting state and 30, 60, and 120 minutes after this meal parallel to plasma glucose, insulin, and serum lipids. We used solid-phase microextraction and gas chromatography-mass spectrometry for detecting changes in 15 VOCs. These VOCs were acetone, ethanol, 1-propanol, 2-propanol, 1-butanol, acetic acid, propionic acid, butyric acid, valeric acid, isovaleric acid, 2-methylbutyric acid, hexanoic acid, acetoin, diacetyl, and phenol. Exhaled breath 2-methylbutyric acid in the fasting state and 1-propanol at 120 minutes decreased (P = .091 for both) after an HFD. Ingestion of the test meal increased ethanol, 1-propanol, acetoin, propionic acid, and butyric acid levels while reducing acetone, 1-butanol, diacetyl, and phenol levels. Both DF diet content and having a single meal affected breathVOCs. Exploring exhaled breath further could help to develop tools for monitoring the metabolic effects of DF.

Inulin-type fructan fermentation by bifidobacteria depends on the strain rather than the species and region in the human intestine

Inulin-type fructans (ITF) are known to cause a health-promoting bifidogenic effect, although the ITF degradation capacity of bifidobacteria in different intestinal regions remains unclear. The present study aims at offering new insights into this link, making use of a collection of 190 bifidobacterial strains, encompassing strains from gut biopsies (terminal ileum and proximal colon; mucosa-associated strains) and the simulator of the human intestinal microbial ecosystem (SHIME®; proximal and distal colon vessels; lumen-associated strains). A multivariate data analysis of all fermentation data revealed four clusters corresponding with different types of ITF degradation fingerprints, which were not correlated with the region in the intestine, suggesting that the degradation of ITF is uniform along the human intestine. Strains from cluster 1 consumed fructose, while strains from cluster 2 consumed more oligofructose than fructose. Higher fructose and oligofructose consumption was characteristic for clusters 3 and 4 strains, which degraded inulin too. In general, the mucosa-associated strains from biopsy origin seemed to be more specialized in the consumption of fructose and oligofructose, while the lumen-associated strains from SHIME origin displayed a higher degradation degree of inulin. Further, intra-species variability in ITF degradation was found, indicating strain-specific variations. The coexistence of different bifidobacterial strains with different ITF degradation fingerprints within the same intestinal region suggests cooperation for the degradation of ITF, with opportunities for cross-feeding on strain and/or species level.

Computational prediction of CRISPR cassettes in gut metagenome samples from Chinese type-2 diabetic patients and healthy controls

Background

CRISPR has been becoming a hot topic as a powerful technique for genome editing for human and other higher organisms. The original CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats coupled with CRISPR-associated proteins) is an important adaptive defence system for prokaryotes that provides resistance against invading elements such as viruses and plasmids. A CRISPR cassette contains short nucleotide sequences called spacers. These unique regions retain a history of the interactions between prokaryotes and their invaders in individual strains and ecosystems. One important ecosystem in the human body is the human gut, a rich habitat populated by a great diversity of microorganisms. Gut microbiomes are important for human physiology and health. Metagenome sequencing has been widely applied for studying the gut microbiomes. Most efforts in metagenome study has been focused on profiling taxa compositions and gene catalogues and identifying their associations with human health. Less attention has been paid to the analysis of the ecosystems of microbiomes themselves especially their CRISPR composition.

Results

We conducted a preliminary analysis of CRISPR sequences in a human gut metagenomic data set of Chinese individuals of type-2 diabetes patients and healthy controls. Applying an available CRISPR-identification algorithm, PILER-CR, we identified 3169 CRISPR cassettes in the data, from which we constructed a set of 1302 unique repeat sequences and 36,709 spacers. A more extensive analysis was made for the CRISPR repeats: these repeats were submitted to a more comprehensive clustering and classification using the web server tool CRISPRmap. All repeats were compared with known CRISPRs in the database CRISPRdb. A total of 784 repeats had matches in the database, and the remaining 518 repeats from our set are potentially novel ones.

Conclusions

The computational analysis of CRISPR composition based contigs of metagenome sequencing data is feasible. It provides an efficient approach for finding potential novel CRISPR arrays and for analysing the ecosystem and history of human microbiomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12918-015-0248-x) contains supplementary material, which is available to authorized users.

1H-NMR based metabolomics study for the detection of the human urine metabolic profile effects of Origanum dictamnus tea ingestion

NMR based metabolomics clarify theOriganum dictamnustea effect upon the human urine metabolome.

Comparative metabolomics in vegans and omnivores reveal constraints on diet-dependent gut microbiota metabolite production

OBJECTIVE

The consumption of an agrarian diet is associated with a reduced risk for many diseases associated with a 'Westernised' lifestyle. Studies suggest that diet affects the gut microbiota, which subsequently influences the metabolome, thereby connecting diet, microbiota and health. However, the degree to which diet influences the composition of the gut microbiota is controversial. Murine models and studies comparing the gut microbiota in humans residing in agrarian versus Western societies suggest that the influence is large. To separate global environmental influences from dietary influences, we characterised the gut microbiota and the host metabolome of individuals consuming an agrarian diet in Western society.

DESIGN AND RESULTS

Using 16S rRNA-tagged sequencing as well as plasma and urinary metabolomic platforms, we compared measures of dietary intake, gut microbiota composition and the plasma metabolome between healthy human vegans and omnivores, sampled in an urban USA environment. Plasma metabolome of vegans differed markedly from omnivores but the gut microbiota was surprisingly similar. Unlike prior studies of individuals living in agrarian societies, higher consumption of fermentable substrate in vegans was not associated with higher levels of faecal short chain fatty acids, a finding confirmed in a 10-day controlled feeding experiment. Similarly, the proportion of vegans capable of producing equol, a soy-based gut microbiota metabolite, was less than that was reported in Asian societies despite the high consumption of soy-based products.

CONCLUSIONS

Evidently, residence in globally distinct societies helps determine the composition of the gut microbiota that, in turn, influences the production of diet-dependent gut microbial metabolites.

Nutrition and the science of disease prevention: a systems approach to support metabolic health

Progress in nutritional science, genetics, computer science, and behavioral economics can be leveraged to address the challenge of noncommunicable disease. This report highlights the connection between nutrition and the complex science of preventing disease and discusses the promotion of optimal metabolic health, building on input from several complementary disciplines. The discussion focuses on (1) the basic science of optimal metabolic health, including data from gene-diet interactions, microbiome, and epidemiological research in nutrition, with the goal of defining better targets and interventions, and (2) how nutrition, from pharma to lifestyle, can build on systems science to address complex issues.

New findings on the in vivo antioxidant activity of Curcuma longa extract by an integrated (1)H NMR and HPLC-MS metabolomic approach

Curcuminoids possess powerful antioxidant activity as demonstrated in many chemical in vitro tests and in several in vivo trials. Nevertheless, the mechanism of this activity is not completely elucidated and studies on the in vivo antioxidant effects are still needed. Metabolomics may be used as an attractive approach for such studies and in this paper, we describe the effects of oral administration of a Curcuma longa L. extract (150 mg/kg of total curcuminoids) to 12 healthy rats with particular attention to urinary markers of oxidative stress. The experiment was carried out over 33 days and changes in the 24-h urine samples metabolome were evaluated by (1)H NMR and HPLC-MS. Both techniques produced similar representations for the collected samples confirming our previous study. Modifications of the urinary metabolome lead to the observation of different variables proving the complementarity of (1)H NMR and HPLC-MS for metabolomic purposes. The urinary levels of allantoin, m-tyrosine, 8-hydroxy-2'-deoxyguanosine, and nitrotyrosine were decreased in the treated group thus supporting an in vivo antioxidant effect of the oral administration of Curcuma extract to healthy rats. On the other hand, urinary TMAO levels were higher in the treated compared to the control group suggesting a role of curcumin supplementation on microbiota or on TMAO urinary excretion. Furthermore, the urinary levels of the sulphur containing compounds taurine and cystine were also changed suggesting a role for such constituents in the biochemical pathways involved in Curcuma extract bioactivity and indicating the need for further investigation on the complex role of antioxidant curcumin effects.