BACKGROUND:Increasingly popular low-gluten diets (LGDs) are generally low in fiber; however, it is possible to improve the LGD by using oat-based products. OBJECTIVES:To investigate the changes in fecal microbiome, fasting plasma short-chain fatty acids (SCFAs), and inflammatory markers (IM) during a 6-wk oat- or rice-rich LGD in individuals with increased cardiometabolic risk. METHODS:The participants (n = 69) were allocated into 2 parallel groups following a 6-wk LGD with either oats or rice. Fasting plasma, stool, and dietary information were collected both at the baseline and at the end of the trial. Fecal microbial communities were analyzed by shotgun metagenomics (NovaSeq X Plus) and characterized using metagenomic phylogenetic analysis, version 4 (MetaPhlAn4). Their functional potential was assessed with HUMAnN3 using the MetaCyc database. Plasma SCFAs were quantified by ultra-HPLC-mass spectrometry, and IM were detected and quantified using a 45-cytokine panel (Olink Target). Diet-group differences over time were assessed with a linear mixed-effects model. RESULTS:Dietary information revealed high-oat and low-rice consumption at the baseline for both groups. Overall, the oat-rich LGD increased circulating SCFAs. In particular, butyrate increased more during the oat-rich LGD than during the rice-rich LGD (PtimeXgroup = 0.033). Regarding changes in the fecal microbiome, the rice group had a higher Shannon diversity index after the intervention than the oat group (PTimeXgroup = 0.025) and more changes in the microbiome. This is possibly due to more substantial dietary changes from low rice consumption compared with the habitual diet at baseline. No significant differences between or changes within the groups in IM were observed. CONCLUSIONS:Changing to an oat-rich LGD increases fasting plasma SCFA concentrations without significant effects on the fecal microbiome and IM in individuals with increased cardiometabolic risk. When there is a regular baseline consumption of oats, adopting a low-fiber rice-rich LGD may shift the microbiome toward a potentially unfavorable direction. This trial was registered at clinicaltrials.gov as NCT05526092.

Vaginal function in healthy women is closely associated with a lactobacilli-dominated microbiome. Among the most common conditions arising from dysbiosis are bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC). While the efficacy of oral probiotics for the treatment of BV and VVC is well documented, the role of consuming fermented foods remains underexplored. This systematic review aims to present a systematic evaluation of the potential role of fermented foods in the prevention and treatment of BV and VVC and establish the extant research gap between the realm of the clinical sciences and the field of food science and technology. For this purpose, under the guidance of COST Action CA20128—Promoting Innovation of Fermented Foods (PIMENTO), a systematic literature review was conducted in two phases. PubMed, Scopus, and Cochrane databases were used for Phase I to analyze articles on human trials and observational studies where the intervention/exposure involved oral consumption of fermented food. In Phase II, a two-step search strategy was employed: (i) identifying microorganisms with demonstrated clinical efficacy in managing BV and VVC, and (ii) reviewing food science literature where these strains are utilized for fermentation. It was observed that 87% of the food starter applications exploited only two of the 54 efficacious strains identified through clinical studies, namely Lactobacillus rhamnosus GG and Lactobacillus acidophilus LA-5. Findings underscore the potential of fermented foods as carriers for beneficial microorganisms and their relevance in supporting vaginal health. This review contributes to a deeper understanding of the interplay between nutritional consumption of viable probiotic strains and their importance in immunomodulation, highlighting the need for more integrated research efforts across disciplines. Future research aimed at filling this gap will enable informed clinical decisions and dietary recommendations.

A “postbiotic” is a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host. To encourage collaborative problem-solving to address the issues related to the characterization and quantification of postbiotics, a working group of academic and industry scientists involved in research or commercial production of postbiotics convened at the International Scientific Association for Probiotics and Prebiotics (ISAPP) 2024 meeting. This paper reports the outcomes of that discussion. Postbiotics are potentially compositionally complex mixtures, leading us to anticipate that full characterization and quantification of all components of a postbiotic product is not feasible. However, confirmation of the identity and quantity of the progenitor microorganism(s), quantification of some of its functional components, and a suitable description of the process of inactivation will be needed to assure the product can be sufficiently described and consistently reproduced. Measurement and quantification must be fit for purpose. Some useful methods include flow cytometry (FC), including innovations such as imaging FC, which has evolved into a mainstream technique suited to quantify inanimate cells, and quantitative polymerase chain reaction, which complements FC by enabling quantification and identity of microbes to the strain level. Other methods can be utilized depending on the complexity, type of microorganisms used (bacteria, yeasts, filamentous fungi), number of strains and cell integrity (intact vs. fragmented). Hence, no ‘gold standard’ methodology - analogous to colony-forming units for probiotics - is envisioned for postbiotics. This perspective focuses on the required microbial composition of postbiotics, not on the optional metabolite components, which can be measured using well-established methods. We propose a decision tree to aid deliberation among different quantification methods for postbiotics under development and being commercialized. We recognize that the evolution of technologies will likely result in future refinement of this decision tree, and we emphasize that our intent is not to prescribe a rigid framework, but rather to provide guiding principles on approaches to quantifying postbiotics.

Background:Psychobiotics are microorganisms that modulate brain function via the gut-brain axis and are increasingly studied for their cognitive benefits. Lactobacillus and Bifidobacterium species, widely present in fermented foods, are considered safe and may influence cognition by modulating neuroinflammation, neurotransmitters, and gut barrier integrity. This systematic review examined the effects of foods fermented with these species on cognitive performance in healthy adults and individuals with mild cognitive impairment. Methods:We conducted the systematic review following EFSA guidelines, Cochrane methodology, and a PROSPERO protocol, using CADIMA for study selection and data extraction. PubMed, Scopus, and Cochrane Library were searched (1 January 1970-31 August 2023) for human intervention and observational studies assessing cognitive outcomes after ingestion of foods fermented with Lactobacillus or Bifidobacterium. Eligible populations included healthy adults and individuals with mild cognitive impairment; studies involving disease were excluded. Screening, data extraction, and bias assessment followed Muka et al.'s 24-step guide using ROBINS and Cochrane/CADIMA frameworks. Evidence was synthesized narratively, while a non-systematic component examined food characteristics, potential mechanisms, and factors affecting bioavailability of bioactive constituents. Results:We included 21 studies (8 interventional, 13 observational). The majority of studies reported benefits, particularly in episodic memory, executive functions, and global cognition, but evidence was limited by inadequate controls, small sample sizes, short interventions, inconsistent domain assessment, and incomplete food characterization. Observational studies had larger populations and longer follow-ups but were limited by exposure assessment and depth of cognitive testing. Conclusion:Consumption of foods fermented with Lactobacillus and/or Bifidobacterium species may offer promising cognitive benefits. However, following EFSA's guidance on the substantiation of health claims, the current evidence is "neither convincing nor sufficient" to establish a causal relationship. Well-designed studies with thorough product characterization are needed to substantiate effects and support potential health claims. Systematic review registration:This study was registered at the Open Science Framework (10.17605/OSF.IO/Z6GRW).

Worldwide, fermented foods (FF) are recognized as healthy and safe. Despite the rapid increase of research papers, there is a lack of systematic evaluation of the health benefits and risks of FF. The COST Action CA20128 “Promoting innovation of fermented foods” (PIMENTO) aims to provide a comprehensive assessment on the available evidence by compiling a set of 16 reviews. Seven reviews will cover clinical and biological endpoints associated with major health indicators across several organ systems, including the cardiovascular, gastrointestinal, neurological, immune, and skeletal systems. Nine reviews will address broader biological questions associated with FF including bioactive compounds and vitamin production, nutrient bioavailability and bioaccessibility, the role of FF in healthy diets and personalized nutrition, food safety, regulatory practices, and finally, the health properties of novel and ethnic FF. For each outcome assessed in the reviews, an innovative approach will be adopted based on EFSA’s published guidance for health claim submissions. In particular, each review will be composed of three parts: (1) a systematic review of available human studies; (2) a non-systematic review of the mechanism of action related to the clinical endpoints measured by the human studies identified in part 1; and (3) a non-systematic review of the characterization of the FF investigated in the human studies identified in part 1. The evidence and research gaps derived from the reviews will be summarized and published in the form of a strategic road map that will pave the way for future research on FF.

The early gut microbiota composition is fundamentally important for piglet health, affecting long-term microbiome development and immunity. In this study, the gut microbiota of postparturient dams was compared with that of their offspring in three Finnish pig farms at three growth phases. The differences in fecal microbiota of three study development groups (Good, Poorly, and PrematureDeath) were analyzed at birth (initial exposure phase), weaning (transitional phase), and before slaughter (stable phase). Dam Lactobacillaceae abundance was lower than in piglets at birth. Limosilactobacillus reuteri and Lactobacillus amylovorus were dominantly expressed in dams and their offspring. Altogether 17 piglets (68%) were identified with Lactobacillaceae at the initial exposure phase, divided unevenly among the development groups: 85% of Good, 37.5% of Poorly, and 75% of PrematureDeath pigs. The development group Good was identified with the highest microbial diversity, whereas the development group PrematureDeath had the lowest diversity. After weaning, the abundance and versatility of Lactobacillaceae in piglets diminished, shifting towards the microbiome of the dam. In conclusion, the fecal microbiota of pigs tends to develop towards a similar alpha and beta diversity despite development group and rearing environment.

Numerous studies have established that prebiotic ingredients in foods and dietary supplements may play a role in supporting human health. Over the three decades that have passed since prebiotics were first defined as a concept, research has revealed a complex universe of prebiotic-induced changes to the human microbiota. There are strong indications of a direct link between these prebiotic-induced changes and specific health benefits. However, at the present time, the EU has not permitted use of the term ‘prebiotic’ in connection with an approved health claim. This paper is the outcome of a workshop organized on the 25th October 2023 by the European branch of the International Life Science Institute (ILSI). It provides an overview of the regulatory requirements for authorized health claims in the EU, key areas of prebiotic research, and findings to date in relation to prebiotics and digestive, immune, metabolic and cognitive health. Research gaps and documentation challenges are then explored and a roadmap proposed for achieving authorization of ‘prebiotic’ in the wording of future EU health claims.

Manipulative behaviour that consists of touching or close contact with ears or tails of pen mates is common in pigs and can become damaging. Manipulative behaviour was analysed from video recordings of 45-day-old pigs, and 15 manipulator-control pairs (n = 30) were formed. Controls neither received nor performed manipulative behaviour. Rectal faecal samples of manipulators and controls were compared. 16S PCR was used to identify Lactobacillaceae species and 16S amplicon sequencing to determine faecal microbiota composition. Seven culturable Lactobacillaceae species were identified in control pigs and four in manipulator pigs. Manipulators (p = 0.02) and females (p = 0.005) expressed higher Lactobacillus amylovorus, and a significant interaction was seen (sex * status: p = 0.005) with this sex difference being more marked in controls. Females (p = 0.08) and manipulator pigs (p = 0.07) tended to express higher total Lactobacillaceae. A tendency for an interaction was seen in Limosilactobacillus reuteri (sex * status: p = 0.09). Results suggest a link between observed low diversity in Lactobacillaceae and the development of manipulative behaviour.

The concept of beneficial microbes was first suggested by Elie Metchnikoff who postulated that lactic acid bacteria offered health benefits capable of promoting longevity. Disorders of the intestinal tract were frequently treated with viable nonpathogenic bacteria to change or replace the intestinal microbiota. The German professor Alfred Nissle isolated a nonpathogenic strain of Escherichia coli from the feces of a First World War soldier who did not develop enterocolitis during a severe outbreak of shigellosis. In Japan, Dr. Minoru Shirota isolated Lacticaseibacillus paracasei strain Shirota to battle diarrheal outbreaks. Today, a search of human clinical trials in PubMed shows that over 1500 trials have been published on probiotics. Although these studies are heterogeneous with regard to the strains and populations included, accumulated evidence supports the view that benefits are measurable across many different outcomes that have been assessed. This article is an update of a previous publication in the Journal of Clinical Gastroenterology,1 and is based on the guideline recently posted on the WGO website. Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.2 Our glossary of terms is based on the definitions proposed by the International Scientific Association of Probiotics and Prebiotics. Lactobacilli, along with species of Bifidobacterium, have historically been common probiotics. In 2020, the genus Lactobacillus underwent a major restructuring to better address the wide diversity of microbes assigned to the genus. Twenty-three new genera were defined, including some with well-studied probiotic species (Table 1). TABLE 1 - New Names for Some Prominent Former Lactobacillus Probiotic Species. Still Included in the Lactobacillus Genus are Lactobacillus acidophilus, L. gasseri, L. crispatus, L. johnsonii, L. helveticus, and L. delbrueckii subsp. bulgaricus (Sometimes Abbreviated as L. bulgaricus). Former name New name Lactobacillus casei Lacticaseibacillus casei Lactobacillus paracasei Lacticaseibacillus paracasei Lactobacillus rhamnosus Lacticaseibacillus rhamnosus Lactobacillus plantarum Lactiplantibacillus plantarum Lactobacillus brevis Levilactobacillus brevis Lactobacillus salivarius Ligilactobacillus salivarius Lactobacillus fermentum Limosilactobacillus fermentum Lactobacillus reuteri Limosilactobacillus reuteri From the International Scientific Association for Probiotics and Prebiotics (ISAPP), "The big breakup of Lactobacillus," available at https://www.nestlenutrition-institute.org/infographics/big-breakup-lactobacillus. GLOSSARY OF TERMS - Probiotics Live microorganisms that, when administered in adequate amounts, confer a health benefit on the host Prebiotic A selectively fermented ingredient that results in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefit(s) upon host health Synbiotics A mixture comprising live microorganisms and substrate(s) selectively utilized by host microorganisms that confers a health benefit on the host. There are 2 types of synbiotic: complementary (mixtures of probiotics and prebiotics) and synergistic (mixtures of live microbes selected to utilize a coadministered substrate for a health effect) Postbiotic A preparation of inanimate microorganisms and/or their components that confers a health benefit on the host The yeast Saccharomyces boulardii and some E. coli and Bacillus species are also used. Newcomers to the probiotic ranks include Clostridium butyricum, recently approved as a novel food in the European Union. Lactic Acid Bacteria, which have been used for the preservation of food by fermentation for thousands of years, may also potentially impart health benefits. However, the term "probiotic" should be reserved for live microbes that have been shown in controlled human studies to impart a health benefit. Fermentation is globally applied in the preservation of a range of raw agricultural materials, such as cereals, roots, tubers, fruit and vegetables, milk, meat, and fish. The prebiotic concept, first proposed by Gibson and Roberfroid in 1995,3 is a more recent one than probiotics. The key aspects of a prebiotic are that it is nondigestible by the host and that it leads to health benefits for the consumer through a positive influence on the resident beneficial microbes. The administration or use of prebiotics or probiotics is intended to influence the gut environment, which is inhabited by trillions of microbes, for the benefit of human health. Both probiotics and prebiotics have been shown to have beneficial effects that extend beyond the gut, but this guideline will focus on gut effects. Prebiotics typically consist of nonstarch polysaccharides and oligosaccharides, although other substances are being studied as candidate prebiotics—such as resistant starch, conjugated linoleic acid, and polyphenols. Most prebiotics are used as food ingredients in foods such as biscuits, cereals, chocolate, spreads, and dairy products. Commonly known prebiotics are: Oligofructose (fructooligosaccharide, FOS) Inulin Galactooligosaccharides (GOSs) Lactulose Breast milk oligosaccharides (human milk oligosaccharides or HMOs) Lactulose is a synthetic disaccharide used as a drug for the treatment of constipation and hepatic encephalopathy. The prebiotic oligofructose is found naturally in many foods, such as wheat, onions, bananas, honey, garlic, and leeks. Oligofructose can also be isolated from chicory root or synthesized enzymatically from sucrose. Fermentation of oligofructose in the colon may result in several physiologic effects, including: Increasing the numbers of bifidobacteria in the colon Increasing calcium absorption Increasing fecal weight Shortening gastrointestinal transit time Lowering blood lipid levels However, the extent to which these physiological effects may be experienced by a consumer varies due to a number of factors, including baseline gut microbiota and diet. It has been hypothesized that the increase in colonic bifidobacteria benefits human health by producing compounds that inhibit potential pathogens, by reducing blood ammonia levels, and by producing vitamins and digestive enzymes. Synbiotics were originally described as appropriate combinations of prebiotics and probiotics. More recently, the concept of synbiotics has evolved to include both complementary and synergistic synbiotics. A complementary synbiotic is defined simply as a mixture of probiotic(s) and prebiotic(s), where the 2 components meet the criteria defined for each, including proper characterization, and are used at a dose shown to provide a health benefit. However, a synergistic synbiotic has been described as a mixture of a live microbe selected to utilize a coadministered substrate, which together leads to a documented health benefit. The components of a synergistic synbiotic do not need to independently meet the criteria for a probiotic or prebiotic (Fig. 1).FIGURE 1: Composition of complementary and synergistic synbiotics. A complementary synbiotic combines a prebiotic and a probiotic, which work independently to elicit one or more health benefits. The prebiotic functions by modulating the resident microbiota to elicit a health benefit. The synergistic synbiotic is composed of a substrate that is utilized by the coadministered live microorganism, enhancing its functionality. Components of synergistic synbiotics work together (not independently) to bring about the resulting health benefits. (Reproduced from Swanson et al4 CC BY 4.0).Genera, Species, and Strains Used as Probiotics A probiotic strain is identified by the genus, species, subspecies (if applicable), and an alphanumeric designation that identifies a specific strain (Table 2). In the scientific community, there is an agreed nomenclature for genus, species, and subspecies names. Strain designations, product names, and trade names are not controlled by the scientific community. According to the guidelines of the World Health Organization (WHO) and Food and Agriculture Organization (FAO; http://www.fao.org/3/a-a0512e.pdf), probiotic manufacturers should deposit their strains in an internationally recognized culture collection. Such depositories will give an additional designation to strains. Table 3 shows a few examples of commercial strains and the names associated with them. TABLE 2 - Nomenclature Used for Probiotic Microorganisms Genus Species Subsp. Strain designation International strain depository designation Strain nickname Product name Lacticaseibacillus rhamnosus None GG ATCC 53103 LGG Culturelle Bifidobacterium animalis lactis DN-173 010 CNCM I-2494 Bifidus regularis Activia yogurt Bifidobacterium longum longum 35624 NCIMB 41003 Bifantis Align ATCC (Manassas, Virginia, USA); CNCM (Institut Pasteur, Paris, France); NCIMB (Aberdeen, Scotland). The product commercial name shown in the table may only be used in some countries. ATCC indicates American Type Culture Collection; CNCM, Collection Nationale de Cultures de Microorganismes; NCIMB, National Collection of Industrial, Food and Marine Bacteria. TABLE 3 - Mechanisms of Probiotic and Prebiotic Host Interaction. The Symbiosis Between Microbiota and the Host can be Optimized by Pharmacological or Nutritional Interventions in the Gut Microbial Ecosystem Using Probiotics or Prebiotics Probiotics Immunologic benefits • Activate local macrophages to increase antigen presentation to B lymphocytes and increase secretory immunoglobulin A (IgA) production both locally and systemically • Modulate cytokine profiles • Induce tolerance to food antigens Nonimmunologic benefits • Digest food and compete for nutrients with pathogens • Alter local pH to create an unfavorable local environment for pathogens • Produce bacteriocins to inhibit pathogens • Scavenge superoxide radicals • Stimulate epithelial mucin production • Enhance intestinal barrier function • Compete for adhesion with pathogens • Modify pathogen-derived toxins Prebiotics • Metabolic effects: production of short-chain fatty acids, absorption of ions (Ca, Fe, Mg) • Enhancing host immunity (IgA production, cytokine modulation, etc.) Strain designations for probiotics are important because the most robust approach to probiotic evidence is to link benefits (such as the specific gastrointestinal targets discussed in this guideline) to specific strains or strain combinations of probiotics at the effective dose. Recommendations of probiotics, especially in a clinical setting, should tie specific strains to the claimed benefits based on human studies. Some strains will have unique properties that may account for certain neurological, immunological, and antimicrobial activities. However, an emerging concept in the field of probiotics is to recognize that some mechanisms of probiotic activity are likely shared among different strains, species, or even genera. Many probiotics may function in a similar manner with regard to their ability to foster colonization resistance, regulate intestinal transit, or normalize perturbed microbiota. For example, the ability to enhance short-chain fatty acid production or reduce luminal pH in the colon may be a core benefit expressed by many different probiotic strains. Thus, some probiotic benefits may be delivered by different strains of certain well-studied species of probiotic genera. It is now common in the field of probiotics for systematic reviews and meta-analyses to include multiple strains. Such an approach is valid if shared mechanisms of action among the different strains included are demonstrated to be responsible for the benefit being assessed. Otherwise, such efforts should focus on strain-specific evidence. Colonizing Microbiota The functions of both probiotics and prebiotics for gastrointestinal end points are interwoven with the microbes that reside in the human gut. Prebiotics are utilized by beneficial members of the commensal microbial community, thereby promoting health. Crosstalk between probiotics and host cells or probiotics and resident microbes provides a key mechanism for influencing the host's health. The intestine contains a large number of microbes, located mainly in the colon and comprising hundreds of species. Estimates suggest that over 40 trillion bacterial cells are harbored in the colon of an adult human being (including a small proportion of Archaea, less than 1%). Fungi and protists are also present, with a negligible contribution in terms of cell numbers, whereas viruses/phages may outnumber bacteria cells. Gut microbes add an average of 600,000 genes to each human being.5 At the level of species and strains, the microbial diversity between individuals is quite remarkable: each individual harbors his or her own distinctive pattern of bacterial composition, determined partly by the host genotype, by initial colonization at birth through vertical transmission, and by dietary habits. In healthy adults, the fecal composition is stable over time. In the human gut ecosystem, the 2 bacterial divisions, Bacteroidetes and Firmicutes, predominate and account for more than 90% of microbes. The rest are Actinobacteria, Proteobacteria, Verrucomicrobia, and Fusobacteria. The normal interaction between gut bacteria and their host is a symbiotic relationship. An important influence of intestinal bacteria on immune function is suggested by the presence of a large number of organized lymphoid structures in the mucosa of the small intestine (Peyer's patches) and large intestine (isolated lymphoid follicles). The epithelium over those structures is specialized for the uptake and sampling of antigens, and they contain lymphoid germinal centers for the induction of adaptive immune responses. In the colon, microorganisms proliferate by fermenting available substrates from diet or endogenous secretions and thereby contribute to host nutrition. Many studies have shown that populations of colonizing microbes differ between healthy individuals and others with disease or unhealthy conditions. However, researchers are not able to define the composition of healthy human microbiota. Certain commensal bacteria (such as Roseburia, Akkermansia, Bifidobacterium, and Faecalibacterium prausnitzii) seem to be associated more commonly with health, but it is a currently active area of research to determine whether supplementation with these bacteria will improve health or reverse disease. Mechanisms of Action of Probiotics and Prebiotics Prebiotics affect intestinal bacteria by enhancing the numbers or activities of beneficial bacteria. This may result in decreasing the population of potentially pathogenic microorganisms or reducing potentially deleterious metabolic activities of host microbiota. Prebiotics may also impact immune function. Probiotic strains may mediate health effects through one or more of several identified mechanisms. Probiotics may affect the intestinal ecosystem by impacting mucosal immune mechanisms, by interacting with commensal or potential pathogenic microbes, by generating metabolic end products such as short-chain fatty acids, and by communicating with host cells through chemical signaling (Fig. 2; Table 3). These mechanisms can lead to antagonism of potential pathogens, an improved intestinal environment, bolstering the intestinal barrier, downregulation of inflammation, and upregulation of the immune response to antigenic challenges. These phenomena are thought to mediate the most beneficial effects, including reduction of the incidence and severity of diarrhea, which is one of the most widely recognized uses of probiotics.FIGURE 2: Mechanisms of microbiota and probiotic interaction with the host. The normal microbiota and probiotics interact with the host in metabolic activities and immune function and prevent colonization of opportunistic and pathogenic microorganisms. (Reproduced with permission from Blackwell Publishing Ltd.; journal through Copyright Clearance Center).Understanding the Marketplace Probiotic-containing products have been successfully marketed in many regions of the world. A range of product types—from conventional food through prescription drugs—is available commercially (Table 4). TABLE 4 - Categories of Products Containing Probiotics Product type Target population Type of claim possible Food Generally healthy Improves or maintains health Meal replacement People with unique nutritional requirements Healthy diet for the target consumer Dietary supplement* General population Improves or maintains health Natural health product† Generally healthy or those with nonsevere medical conditions Improves or maintains health or treats mild conditions Over-the-counter drug People needing to prevent or treat disease Treats mild diseases Prescription drug People needing to prevent or treat disease Treats or prevents disease *Typically tablets, capsules, and sachets containing the bacteria in freeze-dried form.†This category is specific to Canada. The claims that can be made on these types of products differ, depending on regulatory oversight in the region. Most commonly, probiotics and prebiotics are sold as foods or supplement-type products. Typically, no mention of disease or illness is allowed, claims tend to be general, and products are targeted at the generally healthy population. Natural health products represent a specific category in Canada, where the regulatory authorities approve claims and the labeling of the product for use in managing diseases is allowed. From a scientific perspective, suitable descriptions of a probiotic product as reflected on the label should include: Genus, species (and subspecies, if applicable) identification, with nomenclature consistent with current scientifically recognized names Strain designation Viable count of each strain at the end of shelf-life Recommended storage conditions The recommended dose, which should be based on induction of the claimed physiological effect An accurate description of the physiological effect, as allowable by law Contact information for post-market surveillance Products: Dosages and Quality The global market for probiotics was valued at US$ 32.1 billion in 2013, according to a 2015 Grand View Research report. It is predicted that the worldwide probiotic market will progress rapidly at an annual growth rate of 8.1% to reach US$ 85.4 billion by 2027 ("Probiotics Market," https://www.marketsandmarkets.com/). Wading through the multitude of foods, supplements, and pharmaceutical products on the market is a daunting task. Most guidance from medical organizations is based on strains rather than product names, which can differ depending on the geographical region. It can be difficult to match probiotic strains to specific products, and not all products are suitably labeled. An effort to accomplish this has been undertaken in Canada and the United States, funded by unrestricted grants from commercial entities, and does link products to available evidence (see http://www.probioticchart.ca/ and http://usprobioticguide.com/). The quality of probiotic products depends on the manufacturer concerned. Since most are not made to pharmaceutical standards, regulatory authorities may not oversee adherence to quality standards. The issues that are important specifically to probiotic quality include assurance of potency (maintenance of viability, typically indicated by colony-forming units, through the end of shelf-life), purity (manufacturing processes that sufficiently reduce any pathogens of concern), and identity (current nomenclature used to specify the genus, species, and subspecies, if applicable, and a strain designation for each strain in the product). The dose needed for probiotics varies depending on the strain and product. Although many over-the-counter products deliver in the range of 1–10 billion cfu/dose, some products have been shown to be efficacious at lower levels, while some require substantially more. For example, Bifidobacterium longum subsp. longum 35624 was effective in alleviating the symptoms of IBS at 100 million cfu/day, whereas the effective dose of other probiotic products is 300 to 450 billion cfu 3 times daily. It is not possible to state a general dose that is needed for probiotics; the dosage should be based on human studies showing a health benefit. Because probiotics are alive, they are susceptible to die-off during product storage. Manufacturers typically build in overages so that at the end of the product's shelf-life, it does not fall below the potency declared on the label. Responsible manufacturers will indicate the dose expected at the use-by date (not at the time of manufacture). Spore-forming probiotic strains have the advantage of superior resistance to environmental stress during shelf-life. However, robust evidence of the efficacy of spore-formers lags behind that for non–spore-forming probiotics. Probiotic products on the market have been shown in some cases to fail to meet label claims regarding the numbers and types of viable microbes present in the product. Purchasing products from reliable manufacturers is therefore essential. Product Safety Most probiotics in use today are derived either from fermented foods or from the microbes colonizing a healthy human and have been used in products for decades. On the basis of the prevalence of lactobacilli in fermented food, as normal colonizers of the human body, and the low level of infection attributed to them, their pathogenic potential is deemed to be quite low by experts in the field. Bifidobacterium species enjoy a similar safety record. Most products are intended by design for the generally healthy population, so use in persons with compromised immune function or serious underlying disease should be restricted to the strains and indications with proven safety and efficacy for these target patient populations, as described in section 4 below. Microbiological quality standards should meet the needs of at-risk patients, as reviewed by Sanders et al6. Testing or use of newly isolated probiotics or known probiotics for new disease indications are only acceptable after scrutiny and approval by an independent ethics committee. Traditional LAB, long associated with food fermentation, are generally considered safe for oral consumption as part of foods and supplements for the generally healthy population and at levels traditionally used. CLINICAL APPLICATIONS Current insights into the clinical applications (in alphabetical order) for probiotics or prebiotics in gastroenterology are summarized below. It should be noted that the description provides a general overview of clinical efficacy. However, the effects of probiotics are strain-specific and dose-specific, and for prebiotics, the effects are based on the particular formulation. For specific recommendations for different indications on the basis of levels of graded evidence, Tables 6 and 7 should be consulted. Meta-analyses are regarded as providing the highest level of evidence for evaluating clinical efficacy. However, applying meta-analysis to clinical trials with probiotics is fraught with problems due to the heterogeneity of trial designs, the heterogeneity of the probiotic interventions used, the heterogeneity of the populations studied, and the relatively small numbers included in each clinical trial. Such issues can plague meta-analyses conducted on any intervention, but the strain-specificity of effects needs to be carefully taken into account with meta-analyses on probiotics. Combining data on different probiotic strains without a rationale that similar underlying mechanisms of action are driving the effects observed should be avoided when using the results to make medical recommendations. While this section therefore deals with an overview of probiotic efficacy in clinical situations, Tables 6 and 7 detail individual probiotic preparations and clinical situations in which they have been found effective. Treatment of Acute Diarrhea Some probiotic strains are useful in reducing the severity and duration of acute infectious diarrhea in children. Oral administration shortens the duration of acute diarrheal illness in children by ~1 day. Several meta-analyses of controlled clinical trials testing other probiotic strains have been published that show consistent results, suggesting that probiotics are likely to be safe and effective. Prevention of Acute Diarrhea In the prevention of adult and childhood diarrhea, there is evidence that certain probiotics can be effective in some specific settings. A Cochrane meta-analysis based only on large trials with a low risk of bias7 concluded that probiotics probably make little or no difference with diarrhea lasting 48 hours or longer. Early administration of probiotics may therefore be needed. Prevention of Antibiotic-Associated Diarrhea In the prevention of antibiotic-associated diarrhea, there is evidence of efficacy in adults or children who are receiving antibiotic therapy. Meta-analyses concluded that probiotics may provide a moderate effect for preventing antibiotic-associated diarrhea in children,8 adults,9 and elderly adults.10 Prevention of C. difficile Diarrhea A 2017 meta-analysis concluded with moderate certainty that probiotics are effective in preventing C. difficile-associated diarrhea in patients receiving antibiotics.11 Probiotic use in patients who are not immunocompromised or severely debilitated appeared to be safe. The authors also cited the need for further research, but concluded that the data indicate that patients who are at high risk of developing C. difficile-associated diarrhea would benefit from being informed of the potential benefits and harms of probiotics. Prevention of Radiation-induced Diarrhea The gut microbiota may play an important role in radiation-induced diarrhea by reinforcing intestinal barrier function, improving innate immunity, and stimulating intestinal repair mechanisms. A 2013 meta-analysis concluded that probiotics may be beneficial in the prevention and possibly in the treatment of radiation-induced diarrhea.12 Helicobacter Pylori Eradication The 2022 Maastricht VI/Florence Consensus Report on the management of H. pylori infection concluded that certain probiotics have been shown to be effective in reducing gastrointestinal side effects caused by Helicobacter pylori eradication therapies and thus have a beneficial effect on the treatment. However, the quality of the evidence was weak, and the grade of recommendation was moderate.13 There is no evidence to support the concept that a probiotic alone, without concomitant antibiotic therapy, would be effective. Instead, probiotics appear to increase the H. pylori eradication rate by reducing side effects related to eradication therapy rather than through direct effects on H. pylori. Hepatic Encephalopathy Prevention and Treatment Prebiotics such as lactulose are commonly used for the prevention and treatment of hepatic encephalopathy. Evidence for 1 probiotic mixture suggests that it can reverse minimal hepatic encephalopathy. A 2017 Cochrane meta-analysis found that evidence from 3 studies on the benefits of probiotics for people with hepatic encephalopathy was of low quality.14 Although no difference in the mortality rate was observed, the authors concluded that probiotics may improve recovery, quality of life, and plasma ammonia concentrations. Immune Response There is suggestive evidence that several probiotic strains and the prebiotic oligofructose are useful in improving the immune response. Evidence suggestive of enhanced immune responses has been obtained in studies aimed at preventing acute infectious disease (nosocomial diarrhea in children, influenza episodes in winter) and in studies that tested antibody responses to vaccines. Pouchitis There is evidence for the usefulness of a probiotic mix in preventing an initial attack of pouchitis and in preventing further relapse after the induction of remission with antibiotics. The probiotic mix is recommended for adults and children with pouchitis of mild activity or as maintenance therapy for those in remission.15 Ulcerative Colitis Individual studies show that certain probiotics may be safe and as effective as conventional therapy in response and remission rates in mild to moderately active ulcerative colitis in both adult and pediatric populations. However, a 2020 Cochrane meta-analysis concluded that evidence for the induction of remission in mild to moderate ulcerative colitis was of low certainty, and there was no evidence that probiotics were effective in more severe diseases.16 Crohn's Disease Studies of probiotics in Crohn's disease have indicated that there is no evidence to suggest that they are beneficial for the induction or maintenance of remission of Crohn's disease. Irritable Bowel Syndrome (IBS) A reduction in abdominal bloating and flatulence as a result of probiotic treatments is a consistent finding in published studies; some strains may ameliorate pain and provide global relief. The literature suggests that certain probiotics may alleviate symptoms and improve the quality of life in persons with functional abdominal pain. Strain-specific effects of certain probiotics on IBS symptoms are shown in Tables 6 and 7. Infant Colic L. reuteri DSM 17938 and B. animalis ssp. lactis BB12 have been shown to reduce crying time in breastfed infants with colic (Table 7). Lactose Malabsorption Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus improves lactose digestion and reduces symptoms related to lactose intolerance.

Diverse terms have been used in the literature to refer to the health benefits obtained from the administration of non-viable microorganisms or their cell fragments and metabolites. In an effort to provide continuity to this emerging field, the International Scientific Association of Probiotics and Prebiotics (ISAPP) convened a panel of experts to consider this category of substances and adopted the term postbiotic, which they defined as a "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host." This definition does not stipulate any specific health benefit, finished product, target population or regulatory status. In this perspective article, we focused on postbiotics developed for pharmaceutical uses, including medicinal products and medical devices. We address how this field is regulated for products based on inanimate microorganisms, marketing considerations and existing examples of postbiotics products developed as cosmetics for the skin, for vaginal health, and as orally consumed products. We focus on the European Union for regulatory aspects, but also give examples from other geographical areas.

PURPOSE OF REVIEW:The aim is to provide updated information on the concept of postbiotics and recent data on the efficacy of postbiotics for the prevention and treatment of childhood diseases.RECENT FINDINGS:In line with a recently proposed consensus definition, a postbiotic is 'a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host'. Although inanimate, postbiotics may exert health benefits. There are only limited data on infant formulas containing postbiotics, but they are well tolerated, support adequate growth and demonstrate no potential identifiable risks, although clinical benefits remain limited. Currently, there is only limited support for postbiotic use for treating diarrhoea and preventing common paediatric infectious diseases in young children. Given the limited evidence, sometimes with a high risk of bias, caution is justified. No data in older children and adolescents are available.SUMMARY:The consensus definition of postbiotics facilitates further research. As not all postbiotics are the same, the type of disease and specific postbiotic studied should be considered when choosing postbiotics for the prevention or treatment of childhood diseases. Additional studies are needed to assess disease conditions responsive to postbiotics. Mechanisms of action of postbiotics need to be evaluated and characterized.

Importance:Systematic reviews and meta-analyses often report conflicting results when assessing evidence for probiotic efficacy, partially because of the lack of understanding of the unique features of probiotic trials. As a consequence, clinical decisions on the use of probiotics have been confusing. Objective:To provide recommendations to improve the quality and consistency of systematic reviews with meta-analyses on probiotics, so evidence-based clinical decisions can be made with more clarity. Evidence Review:For this consensus statement, an updated literature review was conducted (January 1, 2020, to June 30, 2022) to supplement a previously published 2018 literature search to identify areas where probiotic systematic reviews with meta-analyses might be improved. An expert panel of 21 scientists and physicians with experience on writing and reviewing probiotic reviews and meta-analyses was convened and used a modified Delphi method to develop recommendations for future probiotic reviews. Findings:A total of 206 systematic reviews with meta-analysis components on probiotics were screened and representative examples discussed to determine areas for improvement. The expert panel initially identified 36 items that were inconsistently reported or were considered important to consider in probiotic meta-analyses. Of these, a consensus was reached for 9 recommendations to improve the quality of future probiotic meta-analyses. Conclusions and Relevance:In this study, the expert panel reached a consensus on 9 recommendations that should promote improved reporting of probiotic systematic reviews with meta-analyses and, thereby, assist in clinical decisions regarding the use of probiotics.

Fermented foods are often erroneously equated with probiotics. Although they might act as delivery vehicles for probiotics, or other ‘biotic’ substances, including prebiotics, synbiotics, and postbiotics, stringent criteria must be met for a fermented food to be considered a ‘biotic’. Those criteria include documented health benefit, sufficient product characterization (for probiotics to the strain level) and testing. Similar to other functional ingredients, the health benefits must go beyond that of the product’s nutritional components and food matrix. Therefore, the ‘fermented food’ and ‘probiotic’ terms may not be used interchangeably. This concept would apply to the other biotics as well. In this context, the capacity of fermented foods to deliver one, several, or all biotics defined so far will depend on the microbiological and chemical level of characterization, the reproducibility of the technological process used to produce the fermented foods, the evidence for health benefits conferred by the biotics, as well as the type and amount of testing carried out to show the probiotic, prebiotic, synbiotic, and postbiotic capacity of that fermented food.

Faecalibacterium prausnitzii is a promising biomarker of a healthy human microbiota. However, previous studies reported the heterogeneity of this species and found the presence of several distinct groups at the species level among F. prausnitzii strains. Our recent study revealed that methods previously developed for quantification of F. prausnitzii were not specific to the species level because of the heterogeneity within the F. prausnitzii species and the application of 16S rRNA gene, which is an invalid genetic marker for the species. Therefore, previously available data failed to provide information on different groups, which limits our understanding of the importance of this organism for host health. Here, we propose an alternative gene marker for quantification of F. prausnitzii-related taxa. A total of nine group-specific primer pairs were designed by targeting rpoA gene sequences. The newly developed rpoA-based qPCR successfully quantified targeted groups. Application of the developed qPCR assay in six healthy adults revealed marked differences in abundance and prevalence among the different targeted groups in stool samples. The developed assay will facilitate detailed understanding of the impact of Faecalibacterium populations at the group level on human health and to understand the links between depletion of specific groups in Faecalibacterium and different human disorders.

ObjectiveGestational diabetes mellitus (GDM) is a condition in which women without diabetes are diagnosed with glucose intolerance during pregnancy, typically in the second or third trimester. Early diagnosis, along with a better understanding of its pathophysiology during the first trimester of pregnancy, may be effective in reducing incidence and associated short-term and long-term morbidities. DesignWe comprehensively profiled the gut microbiome, metabolome, inflammatory cytokines, nutrition and clinical records of 394 women during the first trimester of pregnancy, before GDM diagnosis. We then built a model that can predict GDM onset weeks before it is typically diagnosed. Further, we demonstrated the role of the microbiome in disease using faecal microbiota transplant (FMT) of first trimester samples from pregnant women across three unique cohorts. ResultsWe found elevated levels of proinflammatory cytokines in women who later developed GDM, decreased faecal short-chain fatty acids and altered microbiome. We next confirmed that differences in GDM-associated microbial composition during the first trimester drove inflammation and insulin resistance more than 10 weeks prior to GDM diagnosis using FMT experiments. Following these observations, we used a machine learning approach to predict GDM based on first trimester clinical, microbial and inflammatory markers with high accuracy. ConclusionGDM onset can be identified in the first trimester of pregnancy, earlier than currently accepted. Furthermore, the gut microbiome appears to play a role in inflammation-induced GDM pathogenesis, with interleukin-6 as a potential contributor to pathogenesis. Potential GDM markers, including microbiota, can serve as targets for early diagnostics and therapeutic intervention leading to prevention.

To study (16S rRNA-sequencing) the impact of gestational and corrected ages on the microbiota profile of human milk (HM) of mothers that delivered full-term and pre-term children, HM samples were obtained and classified according to the gestational age as group T (full-term births ≥37 weeks), and group P (pre-term births <37 weeks). Group P was longitudinally followed, and the samples were collected at the full-term corrected gestational age: when the chronological age plus the gestational age were ≥37 weeks (PT group). The HM microbiota composition differed depending on the gestational age (T vs. P). Group T had lower levels of Staphylococcus and higher levels of Rothia and Streptococcus, as compared to group P. The alpha Simpson diversity value was higher in group T than in P, whereas no differences were found between groups T and PT, suggesting a microbial evolution of the composition of group P towards group T over chronological age. Full-term delivery was associated with a greater diversity of microbes in HM. The microbial composition of pre-term HM, at the corrected age, did not show significant differences, as compared to the samples obtained from the full-term group, suggesting that it would be appropriate to consider the corrected age in terms of the composition and the diversity of the milk in future studies.

The term postbiotic was recently defined by an panel of scientists convened by the International Scientific Association of Probiotics and Prebiotics as “a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host.” This definition focused on the progenitor microbial cell or cell fragments, not just metabolites, proteins or carbohydrates they might produce. Although such microbe-produced constituents may be functional ingredients of the preparation, they are not required to be present in a postbiotic according to this definition. In this context, terms previously used such as paraprobiotics, ghostbiotics, heat-inactivated probiotics, non-viable probiotics, cell fragments or cell lysates, among others, align with the term postbiotics as conceived by this definition. The applications of postbiotics to infant nutrition and pediatric and adult gastroenterology, mainly, are under development. Some applications for skin health are also underway. As postbiotics are composed of inanimate microorganisms, they cannot colonize the host. However, they can in theory modify the composition or functions of the host microbiota, although evidence for this is scarce. Clinical results are promising, but, overall, there is limited evidence for postbiotics in healthy populations. For example, postbiotics have been studied in fermented infant formulas. The regulation of the term postbiotic is still in its infancy, as no government or international agency around the world has yet incorporated this term in their regulation.