Dose-response study of probiotic bacteria Bifidobacterium animalis subsp lactis BB-12 and Lactobacillus paracasei subsp paracasei CRL-341 in healthy young adults

Effect of Probiotic Dose Escalation on Gut Microbiota and Clinical Outcomes in Preterm Infants-A Systematic Review

Probiotics are known to decrease incidences of necrotising enterocolitis, feeding intolerance, late-onset sepsis, and mortality in preterm infants. Administering an adequate dose is important for optimizing the benefits and safety of probiotics. We conducted a systematic review to assess the effect of probiotic dose escalation on clinical outcomes and gut microbiota in preterm neonates. We searched PubMed, EMBASE, EMCARE, Medline, Cochrane Library, Google Scholar, and MedNar databases in July 2023. Three studies were included. In one of the randomized studies (n = 149, gestation 27 to 33 weeks), no significant differences in faecal Lactobacillus and Bifidobacterium counts and clinical outcomes were seen between the high- and low-dose groups. There was a trend towards increased Lactobacillus and Bifidobacterium counts in the high-dose group. In the other randomized study (n = 120, birth weight 500 to 2000 gm), smaller infants (500 to 1000 gm) required higher doses to display Lactobacillus in their faeces. The cohort study (n = 12, gestation < 33 weeks) showed a trend towards an increase in faecal abundance of bifidobacteria and bacterial diversity in the B. infantis group with increasing dose/time. Limited evidence suggests a higher dose might improve gut colonization in preterm infants. Further studies are urgently needed to address this gap in the knowledge considering the increasing use of probiotics for preterm infants.

The Different Ways Multi-Strain Probiotics with Different Ratios of Bifidobacterium and Lactobacillus Relieve Constipation Induced by Loperamide in Mice

Constipation is currently one of the most common gastrointestinal disorders, and its causes are diverse. Multi-strain probiotics are often considered a more effective treatment than single-strain probiotics. In this study, a constipation model was constructed using loperamide hydrochloride to evaluate the ability of a multi-strain probiotic combination of four different ratios of Bifidobacterium and Lactobacillus to regulate intestinal flora, relieve constipation, and explore the initial mechanism in mice. After four weeks of probiotic intervention, BM1, BM2, and PB2 effectively relieved constipation; however, the pathways involved were different. The Bifidobacteria-dominated formulations BM1 and BM2 mainly changed the composition and structure of the intestinal flora and significantly decreased the relative abundance of Tyzzerella, Enterorhabdus, Faecalibaculum, Gordonibacter, and Mucispirillum in stool; increased the relative abundance of Parabacteroides and the content of short-chain fatty acids (SCFAs) in stool; restored motilin (MTL) and vasoactive intestinal peptide (VIP) levels; and downregulated interleukin 6 (IL-6) and IL-8 levels in serum. This repaired the inflammatory response caused by constipation. Finally, it promoted peristalsis of the gastrointestinal tract, increasing stool water content, and relieving constipation. While Lactobacillus-dominated formula PB2 mainly restored the levels of serum neurotransmitters (MTL, SP (substance P), VIP and PYY (Peptide YY)) and inflammatory factors (IL-1, IL-6 and IL-8), it significantly decreased the relative abundance of Tyzzerella, Enterorhabdus, Faecalibaculum, Gordonibacter and Mucispirillum in stool; it then increased acetic acid content, thereby reducing the level of inflammation and changing stool properties and gastrointestinal motility.

Exploring the Dose–Effect Relationship of Bifidobacterium longum in Relieving Loperamide Hydrochloride-Induced Constipation in Rats through Colon-Released Capsules

Constipation is a common disease affecting humans. Bifidobacterium longum is reportedly effective in relieving constipation. Current studies generally focus on the dose–response relationship of oral doses; however, the dose–effect relationship of B. longum in the colon, which is the primary site where B. longum exerts constipation-relieving effects, to treat constipation has not been studied. Herein, three strains of B. longum (FGSZY6M4, FJSWXJ10M2, and FSDJN6M3) were packaged in colon-released capsules to explore the dose–effect relationship in the colon. For each strain, three groups of capsules (104, 106, and 108 CFU/capsule, respectively) and one group of free probiotics (108 CFU/mL) were used to explore the colonic dose effect of B. longum. The results showed that the three strains of B. longum improved fecal water content and promoted intestinal motility by regulating gastrointestinal peptide (MTL, GAS, and VIP), aquaporin-3, and 5-hydroxytryptamine levels while promoting gastrointestinal motility and relieving constipation by regulating the intestinal flora composition of constipated rats and changing their metabolite content (short-chain fatty acids). Among the three free bacterial solution groups (108 CFU/mL), FGSZY6M4 was the most effective in relieving constipation caused by loperamide hydrochloride in rats. The optimal effective dose of each strain was 6M4 (104 CFU/day), 10M2 (106 CFU/day), and S3 (108 CFU/day) of the colon-released capsules. Therefore, for some effective strains, the dose of oral probiotics can be reduced by colon-released capsules, and constipation can be relieved without administering a great number of bacterial solutions. Therefore, investigating the most effective dose of B. longum at the colon site can help to improve the efficiency of relieving constipation.

Effect of Probiotic Supplementation on Gut Microbiota in Patients with Major Depressive Disorders: A Systematic Review

There is accumulating evidence on the beneficial effects of probiotic supplementation for patients with depressive disorders. However, prior reviews on the topic have largely focused on clinical effectiveness with limited emphasis on the underlying mechanisms of action and effects of probiotics on gut microbiota. In accordance with PRISMA guidelines, a systematic literature search of Medline, EMBASE and the Cochrane Library using combinations of the key words, (“depress*” OR “MDD” OR “suicide”), (“probiotic” OR “Lactobacillus” OR “Bifidobacterium”) AND (“gut” OR “gut micr*” OR “microbiota”), as well as grey literature was performed. We found seven clinical trials involving patients with major depressive disorder (MDD). The small number of studies and heterogeneous sources of data precluded meta-analysis. Most trials (other than one open-label trial) had a low-to-moderate risk of bias, which was largely due to a lack of control for the effects of diet on gut microbiota. Probiotic supplementation yielded only modest effects on depressive symptoms and there were no consistent effects on gut microbiota diversity, and in most instances, no significant alterations in gut microbiota composition were observed after four to eight weeks of probiotic intervention. There is also a lack of systematic reporting on adverse events and no good longer-term data. Patients with MDD may require a longer time to show clinical improvement and the microbial host environment may also need longer than eight weeks to produce significant microbiota alterations. To advance this field, further larger-scale and longer-term studies are required.

The Ability of Streptococcus thermophilus BT01 to Modulate Urease Activity in Healthy Subjects' Fecal Samples Depends on the Biomass Production Process

SCOPE

This study evaluates how manufacturing conditions of probiotic biomass production, using two different cryoprotectants, Cryo-A and Cryo-B, can affect Streptococcus thermophilus BT01 in vivo gastrointestinal tract survival and its ability to modulate the level of urease activity in fecal samples of healthy subjects.

METHODS AND RESULTS

A randomized controlled cross-over study is carried out on 20 adult healthy subjects to evaluate total and viable loads, persistence of S. thermophilus BT01, and urease activity in fecal samples. Strain-specific quantification by using developed culture-based method and molecular qPCR tool allows to quantify viable S. thermophilus BT01 strain in 90% of the subjects. The quantification of both total DNA and recovered viable S. thermophilus BT01 in fecal samples does not reveal significant differences between Cryo-A or Cryo-B treated biomass. However, the administration of S. thermophilus BT01 produced with Cryo-A results in a decreased urease activity in fecal samples compared to Cryo-B protected cells.

CONCLUSION

This study i) highlights how the manufacturing conditions can play a role in influencing the probiotic functionality in vivo and ii) represents the first evidence that links S. thermophilus to a specific probiotic mechanism, the reduction of urease activity in fecal samples.

The Impact of Synbiotic Treatment on the Levels of Gut-Derived Uremic Toxins, Inflammation, and Gut Microbiome of Chronic Kidney Disease Patients-A Randomized Trial

OBJECTIVE

Altering dysbiotic gut flora through synbiotic supplementation has recently been recognized as a potential treatment strategy to reduce the levels of gut-derived uremic toxins and decrease inflammation. Assessing its efficacy and safety has been the main goal of our randomized, double-blind, placebo-controlled study.

METHODS

A total of 34 nondialyzed chronic kidney disease patients, aged ≥18 years, with an estimated glomerular filtration rate between 15 and 45 mL/minute, were randomized either to an intervention group (n = 17), receiving synbiotic (Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium lactis, 32 billion colony forming units per day plus 3.2 g of inulin), or control group (n = 17), receiving placebo during 12 weeks. The impact of treatment on the dynamic of serum levels of gut-derived uremic toxins, total serum indoxyl sulfate, p-cresyl sulfate, and trimethylamine N-oxide, was defined as the primary outcome of the study. Secondary outcomes included changes in the stool microbiome, serum interleukin-6 levels, high-sensitivity C-reactive protein, estimated glomerular filtration rate, albuminuria, diet, gastrointestinal symptom dynamics, and safety. Serum levels of uremic toxins were determined using ultraperformance liquid chromatography. The stool microbiome analysis was performed using the 16S ribosomal ribonucleic acid gene sequencing approach.

RESULTS

Synbiotic treatment significantly modified gut microbiome with Bifidobacteria, Lactobacillus, and Subdoligranulum genera enrichment and consequently reduced serum level of indoxyl sulfate (ΔIS -21.5% vs. 5.3%, P < .001), improved estimated glomerular filtration rate (ΔeGFR 12% vs. 8%, P = .029), and decreased level of high-sensitivity C-reactive protein (-39.5 vs. -8.5%, P < .001) in treated patients. Two patients of the intervention arm complained of increased flatulence. No other safety issues were noted.

CONCLUSION

Synbiotics could be available, safe, and an effective therapeutic strategy we could use in daily practice in order to decrease levels of uremic toxins and microinflammation in chronic kidney disease patients.

Effect of Complex Prebiotics on the Intestinal Colonization Ability of Limosilactobacillus fermentum DALI02

Intestinal colonization is beneficial to the role of probiotics, and prebiotics can promote the adhesion and colonization of probiotics in the intestine. This study optimized the combination of complex prebiotics that could improve the growth ability and adhesion ability of Limosilactobacillus fermentum (L. fermentum) DALI02 to Caco-2 cells in vitro and determined the effect of its colonization quantity and colonization time in the immunocompromised rat model. The results showed that all five prebiotics (fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), inulin, stachyose, and xylo-oligosaccharides (XOS)) significantly promoted the growth and adhesion of L. fermentum DALI02. It was found that 0.5% (w/w) inulin had the best growth promotion effect, and 0.5% FOS had the strongest adhesion promotion (the adhesion rate was increase by 1.75 times). In addition, 0.05% FOS, 0.20% GOS, 0.30% inulin, 0.20% stachyose, and 0.30% XOS could significantly improve the adhesion rate of L. fermentum DALI02 from 1.72% to 3.98%. After 1 w of intervention, the quantity of colonization in the fermented broth with prebiotics group was significantly higher than that in the fermented broth group. The intervention time was extended from 1 d to 4 w, and the amount of colonization of L. fermentum DALI02 in the fermented broth with prebiotics group increased significantly from 4.32 lgcopies/g to 5.12 lgcopies/g. After the intervention, the serum levels of lipopolysaccharide (LPS) and D-lactic acid in rats were significantly reduced, and the most significant was in the fermented broth with prebiotics group, with LPS and D-lactic acid levels of 74.11 pg/mL and 40.33 μmol/L, respectively. Complex prebiotics can promote the growth and adhesion of L. fermentum DALI02 and significantly increase the quantity of colonization and residence time of the strain in the intestine, which helps the restoration of intestinal barrier function and other probiotic effects.

Bifidobacterium animalis subsp. lactis HN019 Effects on Gut Health: A Review

Optimal gut motility is central to bowel function and gut health. The link between the gut dysmotility related disorders and dysfunctional-intestinal barriers has led to a hypothesis that certain probiotics could help in normalizing gut motility and maintain gut health. This review investigates the roles of Bifidobacterium animalis subsp. lactis HN019 (B. lactis HN019™) on gut health, and its mechanisms of action in various pre-clinical and clinical studies. Research supports the hypothesis that B. lactis HN019™ has a beneficial role in maintaining intestinal barrier function during gastrointestinal infections by competing and excluding potential pathogens via different mechanisms; maintaining normal tight junction function in vitro; and regulating host immune defense toward pathogens in both in vitro and human studies. This has been observed to lead to reduced incidence of diarrhea. Interestingly, B. lactis HN019™ also supports normal physiological function in immunosenescent elderly and competes and excludes potential pathogens. Furthermore, B. lactis HN019™ reduced intestinal transit time and increased bowel movement frequency in functional constipation, potentially by modulating gut–brain–microbiota axis, mainly via serotonin signaling pathway, through short chain fatty acids derived from microbial fermentation. B. lactis HN019™ is thus a probiotic that can contribute to relieving gut dysmotility related disorders.

Oral booster probiotic bifidobacteria in SARS-COV-2 patients

Oral booster-single strain probiotic bifidobacteria could be a potential strategy for SARS-CoV-2. This study aims to evaluate the role of oral probiotic Bifidobacterium on moderate/severe SARS-CoV-2 inpatients. In this single-center study, we analyzed data of 44 moderate/severe inpatients with diagnosed COVID-19 in Istanbul Maltepe University Medical Faculty Hospital, 2020 from 1 November 2020 to 15 December 2020. Clinical and medication features were compared and analyzed between patients with or without probiotic. In result, 19 of the 44 patients (43.18%) who were administrated with oral booster-single strain probiotic were discharged with the median inpatient day of 7.6 days which were significantly shorter than those of patients without probiotic. There were significant differences in inpatient days, radiological improvement at day 6 and week 3, and reduction in interleukin-6 levels in those receiving oral probiotic therapy. Although the mortality rate was 5% in the probiotic group, it was 25% in the non-probiotic group. Booster-single strain probiotic bifidobacteria could be an effective treatment strategy for moderate/severe SARS-CoV-2 inpatients to reduce the mortality and length of stay in hospital.

A critical evaluation of the factors affecting the survival and persistence of beneficial bacteria in healthy adults

The efficacy of a probiotic depends on its ability to survive and persist in the digestive tract. Regulatory agencies around the world recommend minimum dosages in order for a product to be termed a probiotic. However, the effect of dosage on the survival of the bacteria in the gut - the primary objective of probiotic administration - has not been critically evaluated. We performed a systematic literature review to assess the available data on the survival rate, during gastrointestinal transit, of probiotic bacteria that were orally administered to healthy adults. We also evaluated the persistence of the administered strain(s) after discontinuation of treatment and the potential role played by the food matrix in which probiotics have been administered. From a regulatory perspective, the profile of the target population is key to establishing the efficacy of probiotics. Therefore, we focussed on subjects without disease conditions. We evaluated 17 studies of single strains and 13 studies of multi-strain products, which reported survival and persistence outcomes. Persistence in the gut and recovery from stool were strain dependent. When the administered dose was higher than 10¹⁰ cfu/day, the probiotic could be recovered from stool regardless of the strain used. Treatment duration did not affect faecal recovery. Thus, dosage recommendations for probiotics by regulatory agencies are lower than that required for a strain to survive, persist and be efficacious in the gut.

Matrix Effects on the Delivery Efficacy of Bifidobacterium animalis subsp. lactis BB-12 on Fecal Microbiota, Gut Transit Time, and Short-Chain Fatty Acids in Healthy Young Adults

Probiotics are consumed in fermented dairy products or as capsules for their putative health benefits. However, little research has been done to evaluate the effects of the delivery matrix on the health benefits of probiotics in humans. To examine the effects of delivering Bifidobacterium animalis subsp. lactis BB-12 (BB-12) (log₁₀ 10 ± 0.5 CFU/day) via a yogurt smoothie versus a capsule, we monitored the fecal microbiota, gut transit times (GTTs), and fecal excretion of short-chain fatty acids (SCFAs) in healthy adults. In a randomized, four-period, crossover study performed in a partially blind manner, 36 adults were recruited and randomly assigned to four treatments: control yogurt smoothie (YS), yogurt smoothie with BB-12 added prefermentation (PRE), yogurt smoothie with BB-12 added postfermentation (POST), and capsule containing BB-12 (CAP). Participants’ fecal microbiota was assessed using 16S rRNA sequencing, GTTs via SmartPill, and fecal SCFAs by gas chromatography (GC) before (baseline) and after each intervention. Participants had significantly higher percentage of Streptococcus after consuming YS versus CAP (P = 0.01). Bifidobacterium-specific terminal restriction fragment length polymorphism analysis revealed a significantly higher percentage of B. animalis after consuming PRE and POST compared to baseline, YS, CAP, and final washout (P < 0.0001). The predominant SCFAs were negatively correlated with GTTs. Consumption of BB-12 delivered in a yogurt smoothie or capsule did not significantly alter the composition of the gut microbiota, GTTs, or fecal SCFA concentration of the study cohort. However, daily consumption of BB-12 in yogurt smoothie may result in higher relative abundance of B. animalis in healthy adults. (This trial has been registered at ClinicalTrials.gov under identifier NCT01399996.)

IMPORTANCEBifidobacterium animalis subsp. lactis BB-12 is a probiotic strain that has been used worldwide since 1985. It has commonly been delivered in fermented dairy products for perceived benefits associated with gut health and enhanced immune function. In addition to fermented dairy products, many new probiotic-containing alternatives such as probiotic-containing juice, probiotic-containing chocolate, and capsules have been developed. While these products provide more options for people to access probiotics, little research has been done on the effect of delivery matrix (dairy versus nondairy) on their efficacy in humans. In addition, it was unclear how yogurt fermentation may influence the survival of BB-12 in the product or on its performance in vivo. The significance of our study is in simultaneously assessing the effect of BB-12, alone and in different delivery vehicles, on the gut transit time, fecal short-chain fatty acids, and the composition of the gut microbiota of the study cohort.

Probiotics and Gut Health in Athletes

PURPOSE OF REVIEW

To provide a focused analysis of the challenges to gut health in athletes and examine recent research aimed at determining the impact of probiotics on preventing gastrointestinal (GI) symptoms and loss of barrier function in athletes.

RECENT FINDINGS

Frequency and severity of GI symptoms during training or competition were reduced by approximately one-third in studies demonstrating efficacy. Improvement of GI symptoms with probiotic supplementation was measured in both single-strain Lactobacillus and multi-strain Lactobacillus and Bifidobacterim probiotics, while improvement in gut barrier function was only measured for multi-strain probiotics. Likelihood of efficacy increased with duration of supplementation. The greatest efficacy for reducing GI symptom frequency and severity, as well as improving or preserving gut barrier function during exercise training and competition, appears to be for multi-strain Lactobacillus and Bifidobacterium probiotic cocktails supplemented for at least 11 weeks.

The impact of probiotic supplementation on metabolic health in healthy women of reproductive age: a systematic review

Products containing probiotics are targeted at healthy or at-risk individuals as a preventative measure to minimise disease risk. Most studies assessing the efficacy of probiotics in humans include a mixture of healthy and unhealthy populations, while studies that focus solely on female populations are largely limited to pregnancy or those with health conditions. Pre-conception is a significant time-point during the life-course, and improving female health status during this period may positively influence future offspring. The objective of this review is to assess the effect of probiotics administered in oral capsule formulation, on metabolic and immune markers in healthy, non-pregnant women of reproductive age. This review followed the PRISMA guidelines. Pubmed, EMBASE, CINAHL, and Web of Science were searched for relevant studies. English language articles relating to randomised-controlled trials were included. The search returned 3250 publications after duplicates were removed. Title (2516), abstract (642), and full text (87) screening excluded 3993 studies from consideration. Five papers were identified with outcomes of interest, and analysis of these showed no conclusive evidence that probiotic capsule supplementation elicited positive effects in this healthy population. This study highlights the need for further research to investigate the role that probiotics play during the pre-conception period, on female metabolic and immune health.

Molecular insights into probiotic mechanisms of action employed against intestinal pathogenic bacteria

Gastrointestinal (GI) diseases, and in particular those caused by bacterial infections, are a major cause of morbidity and mortality worldwide. Treatment is becoming increasingly difficult due to the increase in number of species that have developed resistance to antibiotics. Probiotic lactic acid bacteria (LAB) have considerable potential as alternatives to antibiotics, both in prophylactic and therapeutic applications. Several studies have documented a reduction, or prevention, of GI diseases by probiotic bacteria. Since the activities of probiotic bacteria are closely linked with conditions in the host's GI-tract (GIT) and changes in the population of enteric microorganisms, a deeper understanding of gut-microbial interactions is required in the selection of the most suitable probiotic. This necessitates a deeper understanding of the molecular capabilities of probiotic bacteria. In this review, we explore how probiotic microorganisms interact with enteric pathogens in the GIT. The significance of probiotic colonization and persistence in the GIT is also addressed.

Safety and functional enrichment of gut microbiome in healthy subjects consuming a multi-strain fermented milk product: a randomised controlled trial

Many clinical studies have evaluated the effect of probiotics, but only a few have assessed their dose effects on gut microbiota and host. We conducted a randomized, double-blind, controlled intervention clinical trial to assess the safety (primary endpoint) of and gut microbiota response (secondary endpoint) to the daily ingestion for 4 weeks of two doses (1 or 3 bottles/day) of a fermented milk product (Test) in 96 healthy adults. The Test product is a multi-strain fermented milk product, combining yogurt strains and probiotic candidate strains Lactobacillus paracasei subsp. paracasei CNCM I-1518 and CNCM I-3689 and Lactobacillus rhamnosus CNCM I-3690. We assessed the safety of the Test product on the following parameters: adverse events, vital signs, hematological and metabolic profile, hepatic, kidney or thyroid function, inflammatory markers, bowel habits and digestive symptoms. We explored the longitudinal gut microbiota response to product consumption and dose, by 16S rRNA gene sequencing and functional contribution by shotgun metagenomics. Safety results did not show any significant difference between the Test and Control products whatever the parameters assessed, at the two doses ingested daily over a 4-week-period. Probiotic candidate strains were detected only during consumption period, and at a significantly higher level for the three strains in subjects who consumed 3 products bottles/day. The global structure of the gut microbiota as assessed by alpha and beta-diversity, was not altered by consumption of the product for four weeks. A zero-inflated beta regression model with random effects (ZIBR) identified a few bacterial genera with differential responses to test product consumption dose compared to control. Shotgun metagenomics analysis revealed a functional contribution to the gut microbiome of probiotic candidates.

The Effect of Probiotic Yogurt Containing Lactobacillus Acidophilus LA-5 and Bifidobacterium Lactis BB-12 on Selected Anthropometric Parameters in Obese Individuals on an Energy-Restricted Diet: A Randomized, Controlled Trial

Previous studies using probiotics have shown strain-dependent effects on body mass index (BMI), body mass, or fat mass (FM). The aim of this study was to evaluate how the addition of yogurt containing Lactobacillus acidophilus LA-5 and Bifidobacterium animalis subsp. lactis BB-12 strains to a diet plan affects selected anthropometric parameters in obese people on an energy-restricted diet. Fifty-four subjects aged 20–49 (34.52 ± 9.58) years were included in this study. The recruited subjects were assigned to two subgroups: consuming probiotic yogurt along with a hypocaloric diet (GP) (n–27) or the same diet but without an intentional introduction of yogurt (GRD) (n–27) for 12 weeks. Both GP and GRD decreased body weight, BMI, fat mass and visceral fat by 5.59 kg and 4.71 kg, 1.89 and 1.61 kg/m2, 4.80 kg and 4.07 kg, and 0.68 and 0.65 L, respectively, although the obtained differences were not significant. Analysis of GP and GRD results separately at the beginning and end of the intervention showed that fat loss was substantial in both groups (p < 0.05). Consumption of yogurt containing LA-5 and BB-12 does not significantly improve anthropometric parameters in obese patients.

Restitution of gut microbiota in Ugandan children administered with probiotics (Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis BB-12) during treatment for severe acute malnutrition

Severe acute malnutrition (SAM) is a major challenge in low-income countries and gut microbiota (GM) dysbiosis may play a role in its etiology. Here, we determined the GM evolution during rehabilitation from SAM and the impact of probiotics (Lactobacillus rhamnosus GG and Bifidobacterium animalis subsp. lactis BB-12) supplementation. The GM (16S rRNA gene amplicon sequencing) of children admitted to hospital with SAM showed distinct composition over admission (e.g. Klebsiella spp., and Enterobacteriaceae spp.), discharge (e.g. Clostridiaceae spp., Veilonella dispar) and follow-up (e.g. Lactobacillus ruminis, Blautia spp., Faecalibacterium prausnitzii), reaching similar β- and α-diversity as healthy individuals. Children with diarrhea had reduced distribution of Bacteroidaceae, Lachnospiraceae, increased Enterobacteriaceae and Moraxellaceae, and lower α-diversity. Children suffering from edematous SAM had diminished proportion of Prevotellaceae, Lachnospiraceae, Ruminoccaceae and a higher α-diversity when compared to non-edematous SAM. Supplementation of probiotics did not influence β-diversity upon discharge or follow-up, but it increased (p < .05) the number of observed species [SE: > 4.5]. Children where the probiotic species were detected had lower cumulative incidence (p < .001) of diarrhea during the follow-up period compared to children receiving placebo and children receiving probiotics, but where the probiotics were not detected. The GM of children with non-edematous and edematous SAM differ in composition, which might have implications for future GM targeted treatments. Probiotics treatment reduced the cumulative incidence of diarrhea during the outpatient phase, with the strongest effect in children where the administered probiotics could be detected in the GM.

Microbiota and Lifestyle: A Special Focus on Diet

It is widely known that a good balance and healthy function for bacteria groups in the colon are necessary to maintain homeostasis and preserve health. However, the lack of consensus on what defines a healthy gut microbiota and the multitude of factors that influence human gut microbiota composition complicate the development of appropriate dietary recommendations for our gut microbiota. Furthermore, the varied response to the intake of probiotics and prebiotics observed in healthy adults suggests the existence of potential inter- and intra-individual factors, which might account for gut microbiota changes to a greater extent than diet. The changing dietary habits worldwide involving consumption of processed foods containing artificial ingredients, such as sweeteners; the coincident rise in emotional disorders; and the worsening of other lifestyle habits, such as smoking habits, drug consumption, and sleep, can together contribute to gut dysbiosis and health impairment, as well as the development of chronic diseases. This review summarizes the current literature on the effects of specific dietary ingredients (probiotics, prebiotics, alcohol, refined sugars and sweeteners, fats) in the gut microbiota of healthy adults and the potential inter- and intra-individual factors involved, as well as the influence of other potential lifestyle factors that are dramatically increasing nowadays.

Effects of Prebiotic and Probiotic Supplementation on Lactase Deficiency and Lactose Intolerance: A Systematic Review of Controlled Trials

Lactose intolerance (LI) is characterized by the presence of primarily gastrointestinal clinical signs resulting from colonic fermentation of lactose, the absorption of which is impaired due to a deficiency in the lactase enzyme. These clinical signs can be modified by several factors, including lactose dose, residual lactase expression, concurrent ingestion of other dietary components, gut-transit time, and enteric microbiome composition. In many of individuals with lactose malabsorption, clinical signs may be absent after consumption of normal amounts of milk or, in particular, dairy products (yogurt and cheese), which contain lactose partially digested by live bacteria. The intestinal microbiota can be modulated by biotic supplementation, which may alleviate the signs and symptoms of LI. This systematic review summarizes the available evidence on the influence of prebiotics and probiotics on lactase deficiency and LI. The literature search was conducted using the MEDLINE (via PUBMED) and SCOPUS databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and included randomized controlled trials. For each study selected, the risk of bias was assessed following the Cochrane Collaboration methodology. Our findings showed varying degrees of efficacy but an overall positive relationship between probiotics and LI in relation to specific strains and concentrations. Limitations regarding the wide heterogeneity between the studies included in this review should be taken into account. Only one study examined the benefits of prebiotic supplementation and LI. So further clinical trials are needed in order to gather more evidence.

Efficacy of probiotics on cognition, and biomarkers of inflammation and oxidative stress in adults with Alzheimer's disease or mild cognitive impairment - a meta-analysis of randomized controlled trials

Probiotics are live microbes that confer health benefits to the host. Preliminary animal evidence supports the potential role of probiotics in ameliorating cognitive health, however, findings from clinical trials in Alzheimer’s disease (AD) or mild cognitive impairment (MCI) subjects are controversial. Thus, a meta-analysis is needed to clarify the efficacy of probiotics on cognition in AD or MCI patients. EMBASE, PubMed, Web of Science and Cochrane library were systematically searched and manually screened for relevant published randomized controlled trials (RCTs). Among the 890 citations identified, 5 studies involving 297 subjects met eligibility. There was a significant improvement in cognition (SMD = 0.37; 95% CI, 0.14, 0.61; P = 0.002; I² = 24%), while a significant reduction in malondialdehyde (SMD = −0.60; 95% CI, −0.91, −0.28; P = 0.000; I² = 0.0%) and high-sensitivity C-reactive protein (SMD = −0.57; 95% CI, −0.95, −0.20; P = 0.003; I² = 0.0%) post-intervention levels between the probiotics and control group. This meta-analysis indicated that probiotics improved cognitive performance in AD or MCI patients, possibly through decreasing levels of inflammatory and oxidative biomarkers. However, current evidence is insufficient, and more reliable evidence from large-scale, long-period, RCT is needed.

International Society of Sports Nutrition Position Stand: Probiotics

Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the mechanisms and use of probiotic supplementation to optimize the health, performance, and recovery of athletes. Based on the current available literature, the conclusions of the ISSN are as follows: 1)Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host (FAO/WHO).2)Probiotic administration has been linked to a multitude of health benefits, with gut and immune health being the most researched applications.3)Despite the existence of shared, core mechanisms for probiotic function, health benefits of probiotics are strain- and dose-dependent.4)Athletes have varying gut microbiota compositions that appear to reflect the activity level of the host in comparison to sedentary people, with the differences linked primarily to the volume of exercise and amount of protein consumption. Whether differences in gut microbiota composition affect probiotic efficacy is unknown.5)The main function of the gut is to digest food and absorb nutrients. In athletic populations, certain probiotics strains can increase absorption of key nutrients such as amino acids from protein, and affect the pharmacology and physiological properties of multiple food components.6)Immune depression in athletes worsens with excessive training load, psychological stress, disturbed sleep, and environmental extremes, all of which can contribute to an increased risk of respiratory tract infections. In certain situations, including exposure to crowds, foreign travel and poor hygiene at home, and training or competition venues, athletes' exposure to pathogens may be elevated leading to increased rates of infections. Approximately 70% of the immune system is located in the gut and probiotic supplementation has been shown to promote a healthy immune response. In an athletic population, specific probiotic strains can reduce the number of episodes, severity and duration of upper respiratory tract infections.7)Intense, prolonged exercise, especially in the heat, has been shown to increase gut permeability which potentially can result in systemic toxemia. Specific probiotic strains can improve the integrity of the gut-barrier function in athletes.8)Administration of selected anti-inflammatory probiotic strains have been linked to improved recovery from muscle-damaging exercise.9)The minimal effective dose and method of administration (potency per serving, single vs. split dose, delivery form) of a specific probiotic strain depends on validation studies for this particular strain. Products that contain probiotics must include the genus, species, and strain of each live microorganism on its label as well as the total estimated quantity of each probiotic strain at the end of the product's shelf life, as measured by colony forming units (CFU) or live cells.10)Preclinical and early human research has shown potential probiotic benefits relevant to an athletic population that include improved body composition and lean body mass, normalizing age-related declines in testosterone levels, reductions in cortisol levels indicating improved responses to a physical or mental stressor, reduction of exercise-induced lactate, and increased neurotransmitter synthesis, cognition and mood. However, these potential benefits require validation in more rigorous human studies and in an athletic population.

Dose-dependent and strain-dependent anti-obesity effects of Lactobacillus sakei in a diet induced obese murine model

BACKGROUND

Overweight and abdominal obesity, in addition to medical conditions such as high blood pressure, high blood sugar and triglyceride levels, are typical risk factors associated with metabolic syndrome. Yet, considering the complexity of factors and underlying mechanisms leading to these inflammatory conditions, a deeper understanding of this area is still lacking. Some probiotics have a reputation of a relatively-long history of safe use, and an increasing number of studies are confirming benefits including anti-obesity effects when administered in adequate amounts. Recent reports demonstrate that probiotic functions may widely differ with reference to either intra-species or inter-species related data. Such differences do not necessarily reflect or explain strain-specific functions of a probiotic, and thus require further assessment at the intra-species level. Various anti-obesity clinical trials with probiotics have shown discrepant results and require additional consolidated studies in order to clarify the correct dose of application for reliable and constant efficacy over a long period.

METHODS

Three different strains of Lactobacillus sakei were administered in a high-fat diet induced obese murine model using three different doses, 1 × 1010, 1 × 109 and 1 × 108 CFUs, respectively, per day. Changes in body and organ weight were monitored, and serum chemistry analysis was performed for monitoring obesity associated biomarkers.

RESULTS

Only one strain of L. sakei (CJLS03) induced a dose-dependent anti-obesity effect, while no correlation with either dose or body or adipose tissue weight loss could be detected for the other two L. sakei strains (L338 and L446). The body weight reduction primarily correlated with adipose tissue and obesity-associated serum biomarkers such as triglycerides and aspartate transaminase.

DISCUSSION

This study shows intraspecies diversity of L. sakei and suggests that anti-obesity effects of probiotics may vary in a strain- and dose-specific manner.

Associations of Probiotic Fermented Milk (PFM) and Yogurt Consumption with Bifidobacterium and Lactobacillus Components of the Gut Microbiota in Healthy Adults

The current study investigates whether probiotic fermented milk (PFM) and yogurt consumption (YC) are related to both the ingested bacteria taxa and the overall gut microbiota (GM) composition in healthy adults. PFM and YC habits were analyzed in 260 subjects (51% male) by specific questionnaires, and the following groups were considered: (1) PFM groups: nonconsumers (PFM-NC, n = 175) and consumers (PFM, n = 85), divided as follows: Bifidobacterium-containing PFM (Bif-PFM; n = 33), Lactobacillus-containing PFM (Lb-PFM; n = 14), and mixed Bifidobacterium and Lactobacillus-containing PFM (Mixed-PFM; n = 38); (2) PFM-NC were classified as: yogurt nonconsumers (Y-NC; n = 40) and yogurt consumers (n = 135). GM was analyzed through 16S rRNA sequencing. PFM consumers showed higher Bifidobacteria taxa levels compared to NC, from phylum through to species. Specifically, Bif-PFM consumption was related to higher B. animalis levels (p < 0.001), whereas Lb-PFM consumption was associated to higher levels of Bifidobacterium (p < 0.045) and B. longum (p = 0.011). YC was related to higher levels of the yogurt starter Streptococcus thermophilus (p < 0.001). Lactobacilli and the overall GM were not related either to YC or PFM consumption. According to these results, healthy adults might benefit from PFM intake by increasing Bifidobacterium levels.

Randomised clinical trial: Bifidobacterium lactis NCC2818 probiotic vs placebo, and impact on gut transit time, symptoms, and gut microbiology in chronic constipation

BACKGROUND

Constipation is a prevalent gastrointestinal disorder. Patient dissatisfaction with prescribed medications is common, and there is need for alternative management strategies. Evidence shows that Bifidobacterium species may be beneficial in constipation.

AIM

To investigate changes in physiological and clinical measures of gut function in patients with chronic constipation following the consumption of Bifidobacterium lactis NCC2818, compared to placebo.

METHODS

Participants were randomised to a 4-week supplementation with B. lactis NCC2818 (1.5 x 10¹⁰ CFU/d) or placebo. Gut transit time was measured using a radio-opaque marker, while symptoms and quality of life were assessed using validated questionnaires. Gut microbiota composition was assessed using quantitative polymerase chain reaction. Analysis of covariance was used for normally distributed variables, and Mann-Whitney test for non-normally distributed variables.

RESULTS

Seventy-five participants were randomised. There was no significant difference between the probiotic and placebo groups in gut transit time change from baseline to week 2 (-11.7 hours, SD 33.0 hours vs -12.9 hours, SD 33.6 hours; P = 0.863) or to week 4 (-20.4 hours, SD 32.5 h vs -8.7 hours, SD 33.8 hours; P = 0.103). There were also no improvements in stool output, symptoms, or quality of life. No differences were found in Bifidobacterium concentrations between the probiotic and placebo groups at week 4 (9.5 log₁₀ /g dry faeces, SD 0.3 vs 9.4 log₁₀ /g, SD 1.0; P = 0.509).

CONCLUSIONS

Bifidobacterium lactis NCC2818 was not effective in the management of mild chronic constipation. This study highlights the importance of further studies and their publication to better understand the strain-specific effects of probiotics.

Survival of L. casei DG® (Lactobacillus paracasei CNCMI1572) in the gastrointestinal tract of a healthy paediatric population

Purpose

Ability to survive the digestive process is a major factor in determining the effectiveness of a probiotic. In this study, the ability of the probiotic L. casei DG^® (Lactobacillus paracasei CNCMI1572) to survive gastrointestinal transit in healthy children was investigated for the first time.

Methods

Twenty children aged 3–12 years received L. casei DG^® as drinkable solution of 1 × 10⁹ colony forming units (CFU), once daily for 7 consecutive days. Recovery in faecal samples was evaluated at baseline and at different time-points during and after administration. Defecation frequency, faeces consistency, digestive function and product safety were also assessed.

Results

Nineteen (95%) of the 20 enrolled children presented viable L. casei DG^® cells in their faeces at least once during the study, with a maximum count (mean 4.3 log₁₀ CFU/g ± 2.3) reached between day 4 and 6 from the beginning of consumption. Notably, for 11 (57.9%) of the 19 children with viable cells, L. casei DG^® survived in faecal samples up to 3 days after treatment end. Defecation frequency, faeces consistency and digestive function did not change considerably during or after study treatment. Safety of the study product was very good.

Conclusions

This study showed for the first time that L. casei DG^® survives the gastrointestinal transit when ingested by children with a paediatric probiotic drinkable solution containing 1 × 10⁹ CFU, and persists in the gut up to 3 days after the end of product intake, demonstrating resistance to gastric juices, hydrolytic enzymes and bile acids.

Electronic supplementary material

The online version of this article (10.1007/s00394-018-1860-5) contains supplementary material, which is available to authorized users.

Probiotics in Autoimmune and Inflammatory Disorders

Probiotics have been used to ameliorate gastrointestinal symptoms since ancient times. Over the past 40 years, probiotics have been shown to impact the immune system, both in vivo and in vitro. This interaction is linked to gut microbes, their polysaccharide antigens, and key metabolites produced by these bacteria. At least four metabolic pathways have been implicated in mechanistic studies of probiotics, based on mechanistic studies in animal models. Microbial⁻immune system crosstalk has been linked to: short-chain fatty acid production and signaling, tryptophan metabolism and the activation of aryl hydrocarbon receptors, nucleoside signaling in the gut, and activation of the intestinal histamine-2 receptor. Several randomized controlled trials have now shown that microbial modification by probiotics may improve gastrointestinal symptoms and multiorgan inflammation in rheumatoid arthritis, ulcerative colitis, and multiple sclerosis. Future work will need to carefully assess safety issues, selection of optimal strains and combinations, and attempts to prolong the duration of colonization of beneficial microbes.

Quantitative Recovery of Viable Lactobacillus paracasei CNCM I-1572 (L. casei DG®) After Gastrointestinal Passage in Healthy Adults

Probiotics are live microorganisms, and viability after transit through the gastrointestinal tract (GIT) is considered an inherent property of the health benefits of probiotics. The aim of the present study was to quantify the viable and total loads of Lactobacillus paracasei DG cells after passage through the GIT following the consumption of the probiotic product Enterolactis (L. casei DG®; L. paracasei CNCM I-1572; L. paracasei DG) from drinkable vials by healthy adults. We developed a novel method for discriminating and enumerating culturable L. paracasei DG cells based on the unique sticky, filamentous phenotype of this strain on MRS agar containing vancomycin and kanamycin. The identity of DG was also confirmed with strain-specific primers by colony PCR. This method was used for a recovery study of the DG strain to quantify viable cells in the fecal samples of 20 volunteers during a 1-week probiotic consumption period and a 1-week follow-up. We isolated L. paracasei DG from at least one fecal sample from all the volunteers. The highest concentration of viable DG cells [ranging from 3.6 to 6.7 log₁₀ colony-forming unit (CFU) per gram of feces] in the feces was observed between 4 and 8 days from the beginning of Enterolactis intake and for up to 5 days after cessation of intake. As expected, the total DG count determined by real-time quantitative PCR (qPCR) was mostly higher than the viable DG cells recovered. Viable count experiments, carried out by combining ad hoc culture-based discriminative conditions and strain-specific molecular biological protocols, unambiguously demonstrated that L. paracasei DG can survive gastrointestinal transit in healthy adults when ingested as Enterolactis in drinkable vials containing no less than one billion CFU at the end of shelf life.

Systematic review: probiotics in the management of lower gastrointestinal symptoms - an updated evidence-based international consensus

BACKGROUND

In 2013, a systematic review and Delphi consensus reported that specific probiotics can benefit adult patients with irritable bowel syndrome (IBS) and other gastrointestinal (GI) problems.

AIM

To update the consensus with new evidence.

METHODS

A systematic review identified randomised, placebo-controlled trials published between January 2012 and June 2017. Evidence was graded, previously developed statements were reassessed by an 8-expert panel, and agreement was reached via Delphi consensus.

RESULTS

A total of 70 studies were included (IBS, 34; diarrhoea associated with antibiotics, 13; diarrhoea associated with Helicobacter pylori eradication therapy, 7; other conditions, 16). Of 15 studies that examined global IBS symptoms as a primary endpoint, 8 reported significant benefits of probiotics vs placebo. Consensus statements with 100% agreement and "high" evidence level indicated that specific probiotics help reduce overall symptom burden and abdominal pain in some patients with IBS and duration/intensity of diarrhoea in patients prescribed antibiotics or H. pylori eradication therapy, and have favourable safety. Statements with 70%-100% agreement and "moderate" evidence indicated that, in some patients with IBS, specific probiotics help reduce bloating/distension and improve bowel movement frequency/consistency.

CONCLUSIONS

This updated review indicates that specific probiotics are beneficial in certain lower GI problems, although many of the new publications did not report benefits of probiotics, possibly due to inclusion of new, less efficacious preparations. Specific probiotics can relieve lower GI symptoms in IBS, prevent diarrhoea associated with antibiotics and H. pylori eradication therapy, and show favourable safety. This study will help clinicians recommend/prescribe probiotics for specific symptoms.

Comparative study of probiotic effects of Lactobacillus and Bifidobacteria strains on cholesterol levels, liver morphology and the gut microbiota in obese mice

BACKGROUND

Microbiome-modulating interventions are promising for treatment and prevention of metabolic syndrome. The number of probiotic strains demonstrated ability to decrease cholesterol level in vivo, however, it was poorly confirmed in a clinical setting. The aim was to study the effects of L. acidophilus IMV B-7279, L. casei IMV B-7280, B. animalіs VKL and B. animalіs VKB separately and in various compositions on the level of serum cholesterol, gut microbiota contents and liver morphology on a high-calorie-induced obesity model in BALB/c mice.

MATERIALS AND METHODS

We used for the study female BALB/c mice 6-8 weeks old (18-24 g). Experimental animals were fed by a fat-enriched diet (FED), and 8 experimental groups were formed (12 mice in each group) to test strains of probiotic bacteria L. delbrueckii subsp. bulgaricus IMV B-7281, L. casei IMV B-7280, B. animalіs VKL and B. animalіs VKB and compositions. We used ultrasound for in vivo assessment of the liver and visceral (mesenteric) fat size. In the blood serum of the obese mice, the level of cholesterol was estimated. The liver morphology and gut microbiota of obese mice were studied.

RESULTS

We revealed that after treatment with all of the studied probiotic bacteria and compositions of B. animalis VKL/B. animalis VKB/L. casei IMV B-7280, the weight of obese mice decreased, and cholesterol and its fraction levels in serum were reduced. The size of the liver slightly decreased after treatment with L. delbrueckii subsp. bulgaricus IMV B-7281, B. аnimalis VKB or probiotic compositions; we observed reduction of the mesenteric fat size after injection of all these probiotic bacteria (separately) and probiotic compositions. We defined the strain-dependent effects on serum lipid profiles, liver morphology and the gut microbiota. The B. animalis VKL/B. animalis VKB/L. casei IMV B-7280 composition effectively recovered the liver morphological structure of obese mice. The number of Lactobacillus spp., Bifidobacterium spp. and coliform bacteria increased, the number of staphylococci and streptococci reduced, and the number of microscopic fungi significantly decreased in the gut of obese mice after treatment with L. casei IMV B-7280, L. delbrueckii subsp. bulgaricus IMV B-7281, B. animalis (separately) or their compositions.

CONCLUSION

L. casei IMV B-7280 (separately) and a composition of B. animalis VKL/B. animalis VKB/L. casei IMV B-7280 are effective at decreasing the weight of obese mice, decreasing cholesterol level, restoring the liver morphology and beneficially modulating the gut microbiome in high-calorie-induced obesity.

Lactobacillus johnsonii N6.2 Modulates the Host Immune Responses: A Double-Blind, Randomized Trial in Healthy Adults

Lactobacillus johnsonii N6.2 mitigates the onset of type 1 diabetes (T1D) in biobreeding diabetes-prone rats, in part, through changes in kynurenine:tryptophan (K:T) ratios. The goal of this pilot study was to determine the safety, tolerance, and general immunological response of L. johnsonii N6.2 in healthy subjects. A double-blind, randomized clinical trial in 42 healthy individuals with no known risk factors for T1D was undertaken to evaluate subject responses to the consumption of L. johnsonii N6.2. Participants received 1 capsule/day containing 10⁸ colony-forming units of L. johnsonii N6.2 or placebo for 8 weeks. Comprehensive metabolic panel (CMP), leukocyte subpopulations by complete blood count (CBC) and flow cytometry, serum cytokines, and relevant metabolites in the indoleamine-2,3-dioxygenase pathway were assessed. L. johnsonii N6.2 survival and intestinal microbiota was analyzed. Daily and weekly questionnaires were assessed for potential effects of probiotic treatment on general wellness. The administration of L. johnsonii N6.2 did not modify the CMP or CBC of participants suggesting general safety. In fact, L. johnsonii N6.2 administration significantly decreased the occurrence of abdominal pain, indigestion, and cephalic syndromes. As predicted, increased serum tryptophan levels increased resulting in a decreased K:T ratio was observed in the L. johnsonii N6.2 group. Interestingly, immunophenotyping assays revealed that monocytes and natural killer cell numbers were increased significantly after washout (12 weeks). Moreover, an increase of circulating effector Th1 cells (CD45RO⁺CD183⁺CD196⁻) and cytotoxic CD8⁺ T cells subset was observed in the L. johnsonii N6.2 group. Consumption of L. johnsonii N6.2 is well tolerated in adult control subjects, demonstrates systemic impacts on innate and adaptive immune populations, and results in a decreased K:T ratio. These data provide support for the safety and feasibility of using L. johnsonii N6.2 in prevention trials in subjects at risk for T1D.

Trial registration: This trial was registered at http://clinicaltrials.gov as NCT02349360.

Selective method for identification and quantification of Bifidobacterium animalis subspecies lactis BB-12 (BB-12) from the gastrointestinal tract of healthy volunteers ingesting a combination probiotic of BB-12 and Lactobacillus rhamnosus GG

AIM

To develop a novel validated method for the isolation of Bifidobacterium animalis ssp. lactis BB-12 (BB-12) from faecal specimens and apply it to studies of BB-12 and Lactobacillus rhamnosus GG (LGG) recovered from the healthy human gastrointestinal (GI) tract.

METHODS AND RESULTS

A novel method for isolating and enumerating BB-12 was developed based on its morphologic features of growth on tetracycline-containing agar. The method identified BB-12 correctly from spiked stool close to 100% of the time as validated by PCR confirmation of identity, and resulted in 97-104% recovery of BB-12. The method was then applied in a study of the recovery of BB-12 and LGG from the GI tract of healthy humans consuming ProNutrients^® Probiotic powder sachet containing BB-12 and LGG. Viable BB-12 and LGG were recovered from stool after 21 days of probiotic ingestion compared to baseline. In contrast, no organisms were recovered 21 days after baseline in the nonsupplemented control group.

CONCLUSIONS

We demonstrated recovery of viable BB-12, using a validated novel method specific for the isolation of BB-12, and LGG from the GI tract of healthy humans who consumed the probiotic supplement.

SIGNIFICANCE AND IMPACT OF THE STUDY

This method will enable more detailed and specific studies of BB-12 in probiotic supplements, including when in combination with LGG.

A review of dose-responses of probiotics in human studies

The probiotic definition requires the administration of an 'adequate amount' in order to obtain a health benefit. What that amount should be is not indicated. Here, an overview is given of studies that investigated the dose-response relation of probiotics in human interventions. Studies were divided in; meta-analyses, meta-analyses on specific probiotic strains, and studies testing two or more doses of a probiotic (combination) in the same study. Meta-analyses on the effect of probiotics on antibiotic associated diarrhoea (AAD) suggest a dose-response effect; for Clostridium difficile-associated diarrhoea on the other hand no dose-response was observed. For other end-points; such as necrotising enterocolitis, prevention of atopic dermatitis and slow intestinal transit, no dose-response relation was identified in meta-analyses. For prophylaxis in colorectal cancer and relief of irritable bowel syndrome, no dose-response relation was determined. However, for blood pressure, a meta-analysis observed that higher doses (greater than 10¹¹ cfu) were more effective than lower doses. Meta-analyses of specific strains suggest a break-point for effectiveness of Lactobacillus rhamnosus GG in the treatment of acute gastroenteritis in children; no dose-response was observed for two other probiotics assessed. Studies comparing two or more doses indicate that faecal recovery and risk reduction of AAD follow a positive dose-response relationship. Other end-points such as immune markers, general health, and bowel function did not exhibit clear dose-response relations. For AAD, the findings are very compelling; both meta-analyses and dedicated dose-response studies observe a positive correlation between dose and AAD risk. These findings do not allow for extrapolation, but suggest that studying higher doses for this end-point would be worthwhile. The lack of a clear dose-response for other end-points, does not mean it does not exist; present data does just not allow drawing any conclusions.

Gut microbiota role in irritable bowel syndrome: New therapeutic strategies

In the last decade the impressive expansion of our knowledge of the vast microbial community that resides in the human intestine, the gut microbiota, has provided support to the concept that a disturbed intestinal ecology might promote development and maintenance of symptoms in irritable bowel syndrome (IBS). As a correlate, manipulation of gut microbiota represents a new strategy for the treatment of this multifactorial disease. A number of attempts have been made to modulate the gut bacterial composition, following the idea that expansion of bacterial species considered as beneficial (Lactobacilli and Bifidobacteria) associated with the reduction of those considered harmful (Clostridium, Escherichia coli, Salmonella, Shigella and Pseudomonas) should attenuate IBS symptoms. In this conceptual framework, probiotics appear an attractive option in terms of both efficacy and safety, while prebiotics, synbiotics and antibiotics still need confirmation. Fecal transplant is an old treatment translated from the cure of intestinal infective pathologies that has recently gained a new life as therapeutic option for those patients with a disturbed gut ecosystem, but data on IBS are scanty and randomized, placebo-controlled studies are required.

Effect of Bifidobacterium animalis subsp. lactis GCL2505 on the physiological function of intestine in a rat model

Bifidobacterium animalis ssp. lactis GCL2505 has been shown to proliferate in the human intestine. The intestinal dynamics and physiological effects of GCL2505 as well as the mechanism underlying proliferation in the gut were investigated. GCL2505 showed markedly higher resistance to free bile acids (cholic and deoxycholic acids) than other bifidobacterial species. The intestinal dynamics of GCL2505 and B. longum ssp. longum JCM1217^T was compared. The level of B. animalis ssp. lactis in the GCL2505‐administered group was remarkably higher than that of B. longum in the JCM1217^T‐administered group. The distribution of B. animalis ssp. lactis through the intestine of the GCL2505‐administered group revealed that GCL2505 proliferated in the cecum. The physiological effects of GCL2505 and JCM 1217^T were investigated. The cecal IgA level in the GCL2505‐administered group was significantly higher than that in the nontreated control group. In contrast, the JCM 1217^T‐administered group did not manifest any change in the cecal IgA level. Mucin excretion in the GCL2505‐administered group was significantly higher than that in the JCM 1217^T‐administered group. The thickness of the sulfomucin layer of the colon in the GCL2505‐administered group tended to be higher than that in the JCM 1217^T‐administered group. In a loperamide‐induced constipation model, fecal excretion in the GCL2505‐administered group was significantly increased compared with that in the loperamide‐treated control group. Short‐chain fatty acid concentration in the GCL2505‐administered group was significantly higher than that in the loperamide‐treated control group. These results indicate that the level of proliferation of probiotics in the intestine correlates with the magnitude of host physiological responses, such as IgA production and mucin secretion, which possibly affect gastrointestinal functions such as bowel movement to counteract constipation. GCL2505 exhibits high tolerance to secondary bile acids, which partially explains its higher rate of proliferation in the large intestine.

Effect of the probiotic strain Bifidobacterium animalis subsp. lactis, BB-12®, on defecation frequency in healthy subjects with low defecation frequency and abdominal discomfort: a randomised, double-blind, placebo-controlled, parallel-group trial

The aim of the present study was to investigate the effect of Bifidobacterium animalis subsp. lactis, BB-12^®, on two primary end points – defecation frequency and gastrointestinal (GI) well-being – in healthy adults with low defecation frequency and abdominal discomfort. A total of 1248 subjects were included in a randomised, double-blind, placebo-controlled trial. After a 2-week run-in period, subjects were randomised to 1 or 10 billion colony-forming units/d of the probiotic strain BB-12^® or a matching placebo capsule once daily for 4 weeks. Subjects completed a diary on bowel habits, relief of abdominal discomfort and symptoms. GI well-being, defined as global relief of abdominal discomfort, did not show significant differences. The OR for having a defecation frequency above baseline for ≥50 % of the time was 1·31 (95 % CI 0·98, 1·75), P=0·071, for probiotic treatment overall. Tightening the criteria for being a responder to an increase of ≥1 d/week for ≥50 % of the time resulted in an OR of 1·55 (95 % CI 1·22, 1·96), P=0·0003, for treatment overall. A treatment effect on average defecation frequency was found (P=0·0065), with the frequency being significantly higher compared with placebo at all weeks for probiotic treatment overall (all P<0·05). Effects on defecation frequency were similar for the two doses tested, suggesting that a ceiling effect was reached with the one billion dose. Overall, 4 weeks’ supplementation with the probiotic strain BB-12^® resulted in a clinically relevant benefit on defecation frequency. The results suggest that consumption of BB-12^® improves the GI health of individuals whose symptoms are not sufficiently severe to consult a doctor (ISRCTN18128385).

Short- and long-term dynamics in the intestinal microbiota following ingestion of Bifidobacterium animalis subsp. lactis GCL2505

Bifidobacterium animalis subsp. lactis GCL2505 (B. lactis GCL2505) is able to survive passage through the intestines and proliferate. The daily dynamics of the intestinal bifidobacteria following ingestion of probiotics are not yet clear. Moreover, the effects of long-term ingestion of probiotics on the intestinal microbiota have not been well studied. Two experiments were performed in the present study. In Experiment 1, 53 healthy female volunteers received B. lactis GCL2505; B. bifidum GCL2080, which can survive but not proliferate in the intestine; or yogurt fermented with Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus for 2 weeks, and the daily dynamics of intestinal bifidobacteria were investigated. The number of fecal bifidobacteria significantly increased on day 1, and this was maintained until day 14 in the B. lactis GCL2505 ingestion group. However, no significant change in the number of fecal bifidobacteria was observed in the other groups throughout the ingestion period. In Experiment 2, 38 constipated volunteers received either B. lactis GCL2505 or a placebo for 8 weeks. Both the number of fecal bifidobacteria and the frequency of defecation significantly increased throughout the ingestion period in the B. lactis GCL2505 ingestion group. These results suggested that the proliferation of ingested bifidobacteria within the intestine contributed to a rapid increase in the amount of intestinal bifidobacteria and subsequent maintenance of these levels. Moreover, B. lactis GCL2505 improved the intestinal microbiota more effectively than non-proliferating bifidobacteria and lactic acid bacteria.

Effects of bifidobacterial supplementation to pregnant women and infants in the prevention of allergy development in infants and on fecal microbiota

BACKGROUND

Probiotic administration may be a useful method for preventing allergies in infants; however, there have been controversial results about the efficacy. We investigated the effects of bifidobacterial supplementation on the risk of developing allergic diseases in the Japanese population.

METHODS

In an open trial, we gave Bifidobacterium breve M-16V and Bifidobacterium longum BB536 prenatally to 130 mothers beginning 1 month prior to delivery and postnatally to their infants for 6 months. Another 36 mother-infant pairs served as controls and did not receive the bifidobacterial supplementation. Development of allergic symptoms in the infants was assessed at 4, 10 and 18 months of age. Fecal samples were collected from the mothers and infants.

RESULTS

The risk of developing eczema/atopic dermatitis (AD) during the first 18 months of life was significantly reduced in infants in the probiotic group (OR: 0.231 [95% CI: 0.084-0.628] and 0.304 [0.105-0.892] at 10 and 18 months of age, respectively). Pyrosequencing analyses indicated an altered composition of the fecal microbiota at 4 months for infants who developed eczema/AD at 4 and 10 months of age. The proportion of Proteobacteria was significantly lower (P = 0.007) in mothers at the time of delivery who received the supplementation when compared with the control group and was positively correlated (r = 0.283, P = 0.024) with that of infants at 4 months of age. No adverse effects were related to the use of probiotics.

CONCLUSIONS

These data suggest that the prenatal and postnatal supplementation of bifidobacteria is effective in primary preventing allergic diseases. Some limited changes in the composition of fecal microbiota by the bifidobacterial supplementation were observed.

Effects of genetic, processing, or product formulation changes on efficacy and safety of probiotics

Commercial probiotic strains for food or supplement use can be altered in different ways for a variety of purposes. Production conditions for the strain or final product may be changed to address probiotic yield, functionality, or stability. Final food products may be modified to improve flavor and other sensory properties, provide new product formats, or respond to market opportunities. Such changes can alter the expression of physiological traits owing to the live nature of probiotics. In addition, genetic approaches may be used to improve strain attributes. This review explores whether genetic or phenotypic changes, by accident or design, might affect the efficacy or safety of commercial probiotics. We highlight key issues important to determining the need to re-confirm efficacy or safety after strain improvement, process optimization, or product formulation changes. Research pinpointing the mechanisms of action for probiotic function and the development of assays to measure them are greatly needed to better understand if such changes have a substantive impact on probiotic efficacy.

Evaluation of immune response, microbiota, and blood markers after probiotic bacteria administration in obese mice induced by a high-fat diet

OBJECTIVE

Obesity is associated with alterations in intestinal microbiota and immunity. The aim of this study was to determine the effect of probiotic Lactobacillus casei CRL 431 administration on intestinal and humoral immune response, clinical parameters, and gut microbiota was evaluated using a high-fat diet to induce obesity in a mouse model.

METHODS

Adult mice received a conventional balanced diet or a high-fat diet supplemented with milk, milk fermented by Lactobacillus casei (FM), L. casei as suspension, or water over 60 d. Histology of liver and small intestine (SI), immunoglobulin A-positive cells and macrophages in SI, phagocytic activity of spleen and peritoneal macrophages, and humoral immune response to ovalbumin were studied. Clinical parameters in serum and gut microbiota were also analyzed.

RESULTS

FM was the most effective supplement for decreasing body weight and clinical parameters in serum. The histology of liver and SI was also improved in obese mice given FM. These animals had increased numbers of immunoglobulin A-positive cells and macrophages in SI. The gut microbiota showed that obese mice given probiotics had increased Bacteroides and bifidobacteria. Administration of FM or L. casei as suspension enhanced the phagocytic activity of macrophages. The anti-ovalbumin specific immune response was not increased by any supplement assayed.

CONCLUSION

Administration of probiotics to obese hosts improved the gut microbiota and the mucosal immunity altered by obesity, down-regulated some biochemical parameters in blood associated with metabolic syndrome, and decreased liver steatosis. These results demonstrate the potential use of probiotics in obese individuals to decrease the body weight and to improve the biochemical and immunologic parameters altered by obesity.

The Science behind the Probiotic Strain Bifidobacterium animalis subsp. lactis BB-12(®)

This review presents selected data on the probiotic strain Bifidobacterium animalis subsp. lactis BB-12^® (BB-12^®), which is the world’s most documented probiotic Bifidobacterium. It is described in more than 300 scientific publications out of which more than 130 are publications of human clinical studies. The complete genome sequence of BB-12^® has been determined and published. BB-12^® originates from Chr. Hansen’s collection of dairy cultures and has high stability in foods and as freeze dried powders. Strain characteristics and mechanisms of BB-12^® have been established through extensive in vitro testing. BB-12^® exhibits excellent gastric acid and bile tolerance; it contains bile salt hydrolase, and has strong mucus adherence properties, all valuable probiotic characteristics. Pathogen inhibition, barrier function enhancement, and immune interactions are mechanisms that all have been demonstrated for BB-12^®. BB-12^® has proven its beneficial health effect in numerous clinical studies within gastrointestinal health and immune function. Clinical studies have demonstrated survival of BB-12^® through the gastrointestinal tract and BB-12^® has been shown to support a healthy gastrointestinal microbiota. Furthermore, BB-12^® has been shown to improve bowel function, to have a protective effect against diarrhea, and to reduce side effects of antibiotic treatment, such as antibiotic-associated diarrhea. In terms of immune function, clinical studies have shown that BB-12^® increases the body’s resistance to common respiratory infections as well as reduces the incidence of acute respiratory tract infections.

Consumption of Bifidobacterium lactis Bi-07 by healthy elderly adults enhances phagocytic activity of monocytes and granulocytes

Elderly adults have alterations in their gut microbiota and immune functions that are associated with higher susceptibility to infections and metabolic disorders. Probiotics and prebiotics, and their synbiotic combinations are food supplements that have been shown to improve both gut and immune function. The objective of this randomised, double-blind, placebo-controlled, cross-over human clinical trial was to study immune function and the gut microbiota in healthy elderly adults. Volunteers (n 37) consumed prebiotic galacto-oligosaccharides (GOS; 8 g/d), probiotic Bifidobacterium lactis Bi-07 (Bi-07; 10⁹ colony-forming units/d), their combination (Bi-07 + GOS) and maltodextrin control (8 g/d) in four 3-week periods separated by 4-week wash-out periods. Immune function was analysed by determining the phagocytic and oxidative burst activity of monocytes and granulocytes, whole-blood response to lipopolysaccharide, plasma chemokine concentrations and salivary IgA levels. Gut microbiota composition and faecal SCFA content were determined using 16S ribosomal RNA fluorescence in situ hybridisation and HPLC, respectively. Primary statistical analyses indicated the presence of carry-over effects and thus measurements from only the first supplementation period were considered valid. Subsequent statistical analysis showed that consumption of Bi-07 improved the phagocytic activity of monocytes (P < 0·001) and granulocytes (P = 0·02). Other parameters were unchanged. We have for the first time shown that the probiotic Bi-07 may provide health benefits to elderly individuals by improving the phagocytic activity of monocytes and granulocytes. The present results also suggest that in the elderly, the effects of some probiotics and prebiotics may last longer than in adults.

A comparison of two probiotic strains of bifidobacteria in premature infants

OBJECTIVE

To determine the impact of 2 probiotic bifidobacteria on the fecal microbiota of premature infants fed either human milk or formula.

STUDY DESIGN

In the first of two phase 1 clinical trials, 12 premature infants receiving formula feedings were assigned randomly to receive either Bifidobacterium longum ssp infantis or Bifidobacterium animalis ssp lactis in increasing doses during a 5-week period. In the second, 9 premature infants receiving their mother's milk received each of the two bifidobacteria for 2 weeks separated by a 1-week washout period. Serial stool specimens from each infant were analyzed by terminal restriction fragment-length polymorphism and quantitative polymerase chain reaction for bacterial composition.

RESULTS

Among the formula-fed infants, there was a greater increase in fecal bifidobacteria among infants receiving B infantis (Binf) than those receiving B lactis (Blac). This difference was most marked at a dose of 1.4 × 10(9) colony-forming units twice daily (P < .05). Bacterial diversity improved over dose/time in those infants receiving Binf. Among the human milk-fed infants, greater increases in fecal bifidobacteria and decreases in γ-Proteobacteria followed the administration of Binf than Blac. The B longum group (which includes Binf but not Blac) was the dominant bifidobacteria among the human milk-fed infants, regardless of the probiotic administered.

CONCLUSIONS

Binf was more effective at colonizing the fecal microbiota than Blac in both formula-fed and human milk-fed premature infants. The combination of human milk plus Binf resulted in the greatest fecal levels of bifidobacteria.