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Effects of Wholegrain Compared to Refined Grain Intake on Cardiometabolic Risk Markers, Gut Microbiota, and Gastrointestinal Symptoms in Children: A Randomized Crossover Trial.
Madsen, MTB, Landberg, R, Nielsen, DS, Zhang, Y, Anneberg, OMR, Lauritzen, L, Damsgaard, CT
The American journal of clinical nutrition. 2024;119(1):18-28
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High consumption of wholegrain foods has been linked to a lower risk of cardiovascular disease (CVD) and type 2 diabetes. Some trials have shown benefits to body weight, blood lipids and glucose homeostasis but most of these studies are with adults. Cardiometabolic disease begins in childhood therefore data is needed for this age group to back up dietary recommendations in order to prevent later development of cardiometabolic disease. The aim of this randomized crossover trial was to look at the effects of wholegrain oats and rye intake on serum low-density lipoprotein (LDL), cholesterol and plasma insulin, other cardiometabolic markers, body composition, the composition of the gut microbiome and gastrointestinal symptoms in children with high body mass index (BMI). 55 healthy Danish children (aged 8 – 13) took part. They ate wholegrain oats and rye (WG) or refined grain products (RG) ad libtum for 8 weeks in random order. Measurements were taken at 0, 8 and 16 weeks. Compared with RG, WG reduced LDL cholesterol as well as total:high-density lipoprotein cholesterol and triacylglycerol. WG also modulated the abundance of specific types of gut bacteria, increased plasma acetate, propionate, and butyrate and fecal butyrate and reduced fatigue with no other effects on gut symptoms. This study supports the recommendation to swap refined grain for wholegrain oats and rye in children. Further studies are needed.
Abstract
BACKGROUND Wholegrain intake is associated with lower risk of cardiometabolic diseases in adults, potentially via changes in the gut microbiota. Although cardiometabolic prevention should start early, we lack evidence on the effects in children. OBJECTIVES This study investigated the effects of wholegrain oats and rye intake on serum low-density lipoprotein (LDL) cholesterol and plasma insulin (coprimary outcomes), other cardiometabolic markers, body composition, gut microbiota composition and metabolites, and gastrointestinal symptoms in children with high body mass index (BMI). METHODS In a randomized crossover trial, 55 healthy Danish 8- to 13-y-olds received wholegrain oats and rye ("WG") or refined grain ("RG") products ad libitum for 8 wk in random order. At 0, 8, and 16 wk, we measured anthropometry, body composition by dual-energy absorptiometry, and blood pressure. Fasting blood and fecal samples were collected for analysis of blood lipids, glucose homeostasis markers, gut microbiota, and short-chain fatty acids. Gut symptoms and stool characteristics were determined by questionnaires. Diet was assessed by 4-d dietary records and compliance by plasma alkylresorcinols (ARs). RESULTS Fifty-two children (95%) with a BMI z-score of 1.5 ± 0.6 (mean ± standard deviation) completed the study. They consumed 108 ± 38 and 3 ± 2 g/d wholegrain in the WG and RG period, which was verified by a profound difference in ARs (P < 0.001). Compared with RG, WG reduced LDL cholesterol by 0.14 (95% confidence interval: -0.24, -0.04) mmol/L (P = 0.009) and reduced total:high-density lipoprotein cholesterol (P < 0.001) and triacylglycerol (P = 0.048) without altering body composition or other cardiometabolic markers. WG also modulated the abundance of specific bacterial taxa, increased plasma acetate, propionate, and butyrate and fecal butyrate and reduced fatigue with no other effects on gut symptoms. CONCLUSION High intake of wholegrain oats and rye reduced LDL cholesterol and triacylglycerol, modulated bacterial taxa, and increased beneficial metabolites in children. This supports recommendations of exchanging refined grain with wholegrain oats and rye among children. This trial was registered at clinicaltrials.gov as NCT04430465.
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Efficacy of probiotic treatment as post-exposure prophylaxis for COVID-19: A double-blind, Placebo-Controlled Randomized trial.
Wischmeyer, PE, Tang, H, Ren, Y, Bohannon, L, Jiang, D, Bergens, M, Ramirez, ZE, Andermann, TM, Messina, JA, Sung, JA, et al
Clinical nutrition (Edinburgh, Scotland). 2024;43(1):259-267
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The Coronavirus Disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus infection, continues to pose a unique and novel challenge to global health. Ongoing research is showing a potentially significant role of the microbiome and dysbiosis in COVID-19 disease severity and development of Long-Covid. The aim of this study was to investigate the efficacy of the probiotic Lacticaseibacillus rhamnosus GG (LGG) as post-exposure prophylaxis against COVID-19. This study was a randomised, double-blind, placebo-controlled trial. Participants were randomised to receive LGG or placebo in a 1:1 ratio. Results showed that the participants randomised to LGG had fewer symptoms and prolonged time to development of COVID-19 compared to those receiving placebo. Additionally, probiotic supplementation also reduced symptomatic disease, and changed the gut microbiome structure. Authors conclude that their findings lend credence to the notion that symbiotic microbes may be valuable partners in the fight against COVID-19 and potentially other future pandemic diseases.
Abstract
BACKGROUND & AIMS The COVID-19 pandemic continues to pose unprecedented challenges to worldwide health. While vaccines are effective, additional strategies to mitigate the spread/severity of COVID-19 continue to be needed. Emerging evidence suggests susceptibility to respiratory tract infections in healthy subjects can be reduced by probiotic interventions; thus, probiotics may be a low-risk, low-cost, and easily implementable modality to reduce risk of COVID-19. METHODS In this initial study, we conducted a randomized, double-blind, placebo-controlled trial across the United States testing probiotic Lacticaseibacillus rhamnosus GG (LGG) as postexposure prophylaxis for COVID-19 in 182 participants who had household exposure to someone with confirmed COVID-19 diagnosed within ≤7 days. Participants were randomized to receive oral LGG or placebo for 28 days. The primary outcome was development of illness symptoms within 28 days of COVID-19 exposure. Stool was collected to evaluate microbiome changes. RESULTS Intention-to-treat analysis showed LGG treatment led to a lower likelihood of developing illness symptoms versus placebo (26.4 % vs. 42.9 %, p = 0.02). Further, LGG was associated with a statistically significant reduction in COVID-19 diagnosis (log rank, p = 0.049) via time-to-event analysis. Overall incidence of COVID-19 diagnosis did not significantly differ between LGG and placebo groups (8.8 % vs. 15.4 %, p = 0.17). CONCLUSIONS This data suggests LGG is associated with prolonged time to COVID-19 infection, reduced incidence of illness symptoms, and gut microbiome changes when used as prophylaxis ≤7 days post-COVID-19 exposure, but not overall incidence. This initial work may inform future COVID-19 prevention studies worldwide, particularly in developing nations where Lacticaseibacillus probiotics have previously been utilized to reduce other non-COVID infectious-morbidity. TRIAL REGISTRATION ClinicalTrials.gov, NCT04399252, Date: 22/05/2020. https://clinicaltrials.gov/ct2/show/NCT04399252.
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Exploration of differential responses to FODMAPs and gluten in people with irritable bowel syndrome- a double-blind randomized cross-over challenge study.
Nordin, E, Landberg, R, Hellström, PM, Brunius, C
Metabolomics : Official journal of the Metabolomic Society. 2024;20(2):21
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Irritable bowel syndrome (IBS) is a complex condition characterized by recurrent abdominal pain associated with abnormal bowel habits. Diet is considered a main cause of symptoms in IBS, and fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) are of major concern. The aim of this study was to unravel determinants of differential IBS responses to FODMAP and gluten provocation interventions from molecular data. This study was a randomised, double-blind, placebo-controlled three-way crossover study. Participants were randomised in blocks of 12 into the sequences CBA, ACB, and BAC (A=FODMAPs, B=Gluten, and C=Placebo). Results showed that despite a comprehensive set of methods applied to explore IBS responses, including both regression and classification, predictors of differential response could not be established. Authors concluded by encouraging the application of molecular subtyping methodologies in future studies due to the differential responses to treatment.
Abstract
INTRODUCTION There is large variation in response to diet in irritable bowel syndrome (IBS) and determinants for differential response are poorly understood. OBJECTIVES Our aim was to investigate differential clinical and molecular responses to provocation with fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) and gluten in individuals with IBS. METHODS Data were used from a crossover study with week-long interventions with either FODMAPs, gluten or placebo. The study also included a rapid provocation test. Molecular data consisted of fecal microbiota, short chain fatty acids, and untargeted plasma metabolomics. IBS symptoms were evaluated with the IBS severity scoring system. IBS symptoms were modelled against molecular and baseline questionnaire data, using Random Forest (RF; regression and clustering), Parallel Factor Analysis (PARAFAC), and univariate methods. RESULTS Regression and classification RF models were in general of low predictive power (Q2 ≤ 0.22, classification rate < 0.73). Out of 864 clustering models, only 2 had significant associations to clusters (0.69 < CR < 0.73, p < 0.05), but with no associations to baseline clinical measures. Similarly, PARAFAC revealed no clear association between metabolome data and IBS symptoms. CONCLUSION Differential IBS responses to FODMAPs or gluten exposures could not be explained from clinical and molecular data despite extensive exploration with different data analytical approaches. The trial is registered at www. CLINICALTRIALS gov as NCT03653689 31/08/2018.
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Probiotics fortify intestinal barrier function: a systematic review and meta-analysis of randomized trials.
Zheng, Y, Zhang, Z, Tang, P, Wu, Y, Zhang, A, Li, D, Wang, CZ, Wan, JY, Yao, H, Yuan, CS
Frontiers in immunology. 2023;14:1143548
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Intestinal barrier function is closely related to the pathogenesis of various immune and inflammatory diseases. The intestinal microbiota plays an essential role in maintaining gut homeostasis and functionality in the presence of pro-inflammatory and anti-inflammatory microbes. The aim of this study was to comprehensively evaluate the role of probiotics in contributing to intestinal barrier function, and the related immune function, inflammatory status, and gut microbiota composition. This study was a systematic review of 28 articles (qualitative synthesis), and a meta-analysis of 26 randomised controlled trials. Results showed that probiotics could significantly improve intestinal barrier function according to specific indicators. The meta-analysis also indicated that probiotic supplementation could reduce inflammatory factors. Furthermore, it also demonstrated that probiotics could modulate gut microbiota compositions by elevating the abundances of Bifidobacterium and Lactobacillus. Authors conclude that probiotics could improve intestinal barrier function to some extent, but more high-quality randomised controlled studies are needed to reach a solid conclusion.
Expert Review
Conflicts of interest:
None
Take Home Message:
The probiotics Bifidobacterium and Lactobacillus may be beneficial for health by addressing imbalances in gut bacteria (dysbiosis), reducing inflammation in the gut and improving the integrity and function of the gut barrier
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction
Probiotics are microorganisms that are considered beneficial to health. The aim of this study was to assess the role of probiotics in protecting intestinal barrier function as well as their effects on the composition of gut microbiota, inflammatory status, and immune function for reducing the risk of related diseases.
Methods
26 randomised controlled trials (RCTs) published between 2005-2021 with a total population of n=1891 (n = 955 Intervention, n = 936 controls)) were included in the meta-analysis. Outcome measures were categorised under indicators relating to intestinal barrier function, inflammatory markers, immune function and microbiota composition. Studies were conducted worldwide with participants being healthcare patients or athletes. Study durations ranged from 3 days to 6 months. Different dosages and forms of probiotics were used. Data was pooled for Bifidobacterium, Lactobacillus, Enterobacteriaceae and Enterococcus species.
Results
Gut barrier function in the probiotic groups was improved as measured by transepithelial resistance (TER) mean difference (MD) 5.27 {95% CI, 3.82 to 6.72, p = < 0.00001], lipopolysaccharide (LPS) standardised mean difference (SMD) -0.47 (95% CI, -0.85 to -0.09, p = 0.02), serum zonulin SMD -1.58 (95% CI,-2.49 to -0.66, p = 0.0007), and endotoxin SMD -3.20 (95% CI, -5.41 to - 0.98, p = 0.005).
The inflammatory markers interleukin 6 (IL-6), C-reactive protein (CRP) and tumour necrosis factor-alpha (TNF-a) were also improved compared to control groups. Lactobacillus (95% CI p=0.02) and Bifidobacterium (95% CI, p=0.01) enhanced microbial composition, however, Enterobacteriaceae and Enterococcus species did not. Immune function as measured by Immunoglobulin A (IgA), Immunoglobulin G IgG and Immunoglobulin M (IgM) were not improved.
Conclusion
The findings of this study suggest that intestinal barrier function and microbial composition could be improved using probiotics. They were also found to help alleviate inflammation. Further studies of high quality are however needed to confirm these results.
No conflicts of interest were reported.
Clinical practice applications:
The use of the probiotics Bifidobacterium and Lactobacillus may be beneficial for:
- supporting the integrity of gut barrier function
- improving the composition of gut microbiota
- lowering inflammation
Considerations for future research:
High heterogeneity between studies may affect the applicability of the results. Future research development should focus on the following areas:
- testing methods
- study durations
- measuring indicators
- the type and dose of probiotics
Abstract
BACKGROUND Probiotics play a vital role in treating immune and inflammatory diseases by improving intestinal barrier function; however, a comprehensive evaluation is missing. The present study aimed to explore the impact of probiotics on the intestinal barrier and related immune function, inflammation, and microbiota composition. A systematic review and meta-analyses were conducted. METHODS Four major databases (PubMed, Science Citation Index Expanded, CENTRAL, and Embase) were thoroughly searched. Weighted mean differences were calculated for continuous outcomes with corresponding 95% confidence intervals (CIs), heterogeneity among studies was evaluated utilizing I2 statistic (Chi-Square test), and data were pooled using random effects meta-analyses. RESULTS Meta-analysis of data from a total of 26 RCTs (n = 1891) indicated that probiotics significantly improved gut barrier function measured by levels of TER (MD, 5.27, 95% CI, 3.82 to 6.72, P < 0.00001), serum zonulin (SMD, -1.58, 95% CI, -2.49 to -0.66, P = 0.0007), endotoxin (SMD, -3.20, 95% CI, -5.41 to -0.98, P = 0.005), and LPS (SMD, -0.47, 95% CI, -0.85 to -0.09, P = 0.02). Furthermore, probiotic groups demonstrated better efficacy over control groups in reducing inflammatory factors, including CRP, TNF-α, and IL-6. Probiotics can also modulate the gut microbiota structure by boosting the enrichment of Bifidobacterium and Lactobacillus. CONCLUSION The present work revealed that probiotics could improve intestinal barrier function, and alleviate inflammation and microbial dysbiosis. Further high-quality RCTs are warranted to achieve a more definitive conclusion. CLINICAL TRIAL REGISTRATION https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=281822, identifier CRD42021281822.
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Interactions between Mediterranean Diet Supplemented with Dairy Foods and the Gut Microbiota Influence Cardiovascular Health in an Australian Population.
Choo, JM, Murphy, KJ, Wade, AT, Wang, Y, Bracci, EL, Davis, CR, Dyer, KA, Woodman, RJ, Hodgson, JM, Rogers, GB
Nutrients. 2023;15(16)
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Diet is a fundamental determinant of metabolic health and immune regulation. Long-term dietary patterns also play an important role in shaping the intestinal commensal microbiota. The aim of this study was to explore the effects of an-8 week Mediterranean Diet enriched with dairy foods on the gut microbiome of Australian adults at risk of cardiovascular disease. This study was a randomised controlled trial with a 2 × 2 cross-over design. Participants followed a Mediterranean diet with 3–4 daily serves of dairy foods of 1000–1300mg per day (MedDairy) or low-fat diet (LFD) diet intervention for 8 weeks, separated by an 8-week washout phase where participants returned to their habitual diet. Participants (n= 43) were randomly assigned to their first dietary phase. Results showed that compared to the LFD (control), the MedDairy diet did not result in broad changes to the gut microbiota but significantly altered the relative abundance of selected bacterial taxa. Furthermore, microbial changes, including an increase in Butyricicoccus, were inversely correlated with changes in systolic blood pressure. Authors conclude that an 8-week MedDiet supplemented with dairy foods results in relative abundance changes in bacterial taxa.
Abstract
The impact of a Mediterranean diet on the intestinal microbiome has been linked to its health benefits. We aim to evaluate the effects of a Mediterranean diet supplemented with dairy foods on the gut microbiome in Australians at risk of cardiovascular disease. In a randomised controlled cross-over study, 34 adults with a systolic blood pressure ≥120 mmHg and with risk factors for cardiovascular disease were randomly allocated to a Mediterranean diet with 3-4 daily serves of dairy foods (Australian recommended daily intake (RDI) of 1000-1300 mg per day (MedDairy)) or a low-fat (LFD) control diet. Between each 8-week diet, participants underwent an 8-week washout period. Microbiota characteristics of stool samples collected at the start and end of each diet period were determined by 16S rRNA amplicon sequencing. MedDairy-associated effects on bacterial relative abundance were correlated with clinical, anthropometric, and cognitive outcomes. No change in the overall faecal microbial structure or composition was observed with either diet (p > 0.05). The MedDairy diet was associated with changes in the relative abundance of several bacterial taxa, including an increase in Butyricicoccus and a decrease in Colinsella and Veillonella (p < 0.05). Increases in Butyricicoccus relative abundance over 8 weeks were inversely correlated with lower systolic blood pressure (r = -0.38, p = 0.026) and positively correlated with changes in fasting glucose levels (r = 0.39, p = 0.019), specifically for the MedDairy group. No significant associations were observed between the altered taxa and anthropometric or cognitive measures (p > 0.05). Compared to a low-fat control diet, the MedDairy diet resulted in changes in the abundance of specific gut bacteria, which were associated with clinical outcomes in adults at risk of CVD.
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Effects of FODMAPs and Gluten on Gut Microbiota and Their Association with the Metabolome in Irritable Bowel Syndrome: A Double-Blind, Randomized, Cross-Over Intervention Study.
Nordin, E, Hellström, PM, Dicksved, J, Pelve, E, Landberg, R, Brunius, C
Nutrients. 2023;15(13)
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Irritable bowel syndrome (IBS) is defined as recurring abdominal pain in relation to stool irregularities. The mechanisms behind IBS are poorly understood, but changes in gut microbiota composition, intestinal barrier function, enteroendocrine cell population, low-grade inflammation and gut–brain axis modulations are believed to play a role. The aim of this study was to investigate how fermentable oligo-, di-, mono-saccharides, and polyols (FODMAPs) and gluten affected gut microbiota and circulating metabolite profiles, as well as to investigate potential links between gut microbiota, metabolites, and IBS symptoms. This study was a double-blind, placebo-controlled three-way crossover study. Both the study personnel and participants were blinded. Results showed that consumption of high FODMAP foods, but not gluten, altered the gut microbiota composition, in particular causing changes to microbiota and metabolites, previously associated with improved metabolic health and reduced inflammation. There were also minor effects of FODMAPs and gluten on short-chain fatty acids. Authors conclude that the intake of FODMAP, but not gluten, over one week altered the gut microbiota composition, with only weak associations with IBS symptoms. Healthcare practitioners working with IBS should consider the impacts on the gut microbiome when advising the use of a low-FODMAP diet.
Abstract
BACKGROUND A mechanistic understanding of the effects of dietary treatment in irritable bowel syndrome (IBS) is lacking. Our aim was therefore to investigate how fermentable oligo- di-, monosaccharides, and polyols (FODMAPs) and gluten affected gut microbiota and circulating metabolite profiles, as well as to investigate potential links between gut microbiota, metabolites, and IBS symptoms. METHODS We used data from a double-blind, randomized, crossover study with week-long provocations of FODMAPs, gluten, and placebo in participants with IBS. To study the effects of the provocations on fecal microbiota, fecal and plasma short-chain fatty acids, the untargeted plasma metabolome, and IBS symptoms, we used Random Forest, linear mixed model and Spearman correlation analysis. RESULTS FODMAPs increased fecal saccharolytic bacteria, plasma phenolic-derived metabolites, 3-indolepropionate, and decreased isobutyrate and bile acids. Gluten decreased fecal isovalerate and altered carnitine derivatives, CoA, and fatty acids in plasma. For FODMAPs, modest correlations were observed between microbiota and phenolic-derived metabolites and 3-indolepropionate, previously associated with improved metabolic health, and reduced inflammation. Correlations between molecular data and IBS symptoms were weak. CONCLUSIONS FODMAPs, but not gluten, altered microbiota composition and correlated with phenolic-derived metabolites and 3-indolepropionate, with only weak associations with IBS symptoms. Thus, the minor effect of FODMAPs on IBS symptoms must be weighed against the effect on microbiota and metabolites related to positive health factors.
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The Effect of Probiotic Supplements on Metabolic Parameters of People with Type 2 Diabetes in Greece-A Randomized, Double-Blind, Placebo-Controlled Study.
Zikou, E, Dovrolis, N, Dimosthenopoulos, C, Gazouli, M, Makrilakis, K
Nutrients. 2023;15(21)
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Type 2 diabetes is a multifaceted disease caused by both genetic and environmental factors such as excessive energy intake and lack of exercise. The gut microbiome has been shown to contribute to many different diseases including diabetes through its effects on the immune system, appetite, and fat storage. Probiotics are living organisms that have health benefits to humans and they have been studied for their effects on individuals with type 2 diabetes. However, the studies that have been performed have shown inconsistent results due to poorly designed trials. This randomised control trial aimed to determine the effects of a probiotic supplement containing Lactobacillus, Bifidobacterium, and Saccharomyces species on measures of blood sugar control over a period of 6 months. The results showed that compared to controls, there were significant reductions in measures of blood sugar and total cholesterol. Interestingly the probiotics did not change the diversity of the subjects gut microbiome but did alter their function noting changes in enzymes and metabolites involved in diabetes. It was concluded that over a 6-month period, the supplementation of probiotics containing Lactobacillus, Bifidobacterium, and Saccharomyces was of benefit to blood sugar balance and cholesterol levels. This study could be used by healthcare professionals to recommend a specific probiotic to individuals with type 2 diabetes.
Abstract
The role of probiotic supplementation in type 2 diabetes (T2D) treatment is controversial. The present study aimed to assess the effects of a multi-strain probiotic supplement (LactoLevureR (containing Lactobacillus acidophilus, Lactobacillus plantarum, Bifidobacterium lactis, and Saccharomyces boulardii)) over 6 months, primarily on glycemic control as well as on lipid levels and alterations in the gut microbiome, among individuals with T2D residing in Greece. A total of 91 adults with T2D (mean age [±SD] 65.12 ± 10.92 years, 62.6% males) were randomized to receive the probiotic supplement or a matching placebo capsule, once daily, for 6 months. Blood chemistries and anthropometric parameters were conducted every 3 months, and stool samples were collected at baseline and at 6 months. Significant reductions in HbA1c, fasting blood glucose, and total cholesterol were observed in participants treated with the probiotic supplement (n = 46) compared to the controls (n = 45), even after adjustment for a greater decrease in adiposity (waist circumference). Although there were no statistically significant differences in the diversity of the gut microbiome (α and β diversity), the administration of probiotics did influence several genera, metabolites, and key enzymes associated with diabetes. Overall, the administration of the multi-strain probiotic LactoLevureR over a 6-month period in individuals with T2D was well-tolerated and had a positive impact on metabolic parameters, alongside improvements in indices of adiposity.
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Effect of synbiotic supplementation on immune parameters and gut microbiota in healthy adults: a double-blind randomized controlled trial.
Li, X, Hu, S, Yin, J, Peng, X, King, L, Li, L, Xu, Z, Zhou, L, Peng, Z, Ze, X, et al
Gut microbes. 2023;15(2):2247025
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The gut microbiota is involved in regulating immunity and synbiotics, that is combinations of pro- and prebiotics, may therefore modulate immunity via the gut microbiota. The aim of this randomised, double-blind, placebo-controlled trial was to evaluate the immune-modulatory effects of a synbiotic supplement (containing Bifidobacterium lactis HN019, Lactobacillus rhamnosus HN001 and fructo-oligosaccharide) in healthy adults. Outcome measures included C-reactive protein (CRP, an inflammatory marker), various pro- and anti-inflammatory cytokines, stool and salivary secretory IgA (sIgA), leukocytes, microbial stool analysis and occurrence, duration, and severity of upper respiratory tract infections (URTI). Compared to the control group, a significant reduction in the inflammatory markers CRP and interferon-gamma and an increase in the anti-inflammatory interleukin-10 and stool sIgA were observed in the supplementation group. There were no differences in types of leukocytes or URTIs between groups. Significant favourable changes in microbiome analysis were observed in the supplemented group which correlated with the observed improvements in inflammatory markers. These changes were dependent on the baseline composition of the microbiome. No adverse events were reported. The authors conclude that the data show that synbiotics are of benefit to healthy adults and support the concept of personalised supplementation.
Abstract
Synbiotics are increasingly used by the general population to boost immunity. However, there is limited evidence concerning the immunomodulatory effects of synbiotics in healthy individuals. Therefore, we conducted a double-blind, randomized, placebo-controlled study in 106 healthy adults. Participants were randomly assigned to receive either synbiotics (containing Bifidobacterium lactis HN019 1.5 × 108 CFU/d, Lactobacillus rhamnosus HN001 7.5 × 107 CFU/d, and fructooligosaccharide 500 mg/d) or placebo for 8 weeks. Immune parameters and gut microbiota composition were measured at baseline, mid, and end of the study. Compared to the placebo group, participants receiving synbiotic supplementation exhibited greater reductions in plasma C-reactive protein (P = 0.088) and interferon-gamma (P = 0.008), along with larger increases in plasma interleukin (IL)-10 (P = 0.008) and stool secretory IgA (sIgA) (P = 0.014). Additionally, synbiotic supplementation led to an enrichment of beneficial bacteria (Clostridium_sensu_stricto_1, Lactobacillus, Bifidobacterium, and Collinsella) and several functional pathways related to amino acids and short-chain fatty acids biosynthesis, whereas reduced potential pro-inflammatory Parabacteroides compared to baseline. Importantly, alternations in anti-inflammatory markers (IL-10 and sIgA) were significantly correlated with microbial variations triggered by synbiotic supplementation. Stratification of participants into two enterotypes based on pre-treatment Prevotella-to-Bacteroides (P/B) ratio revealed a more favorable effect of synbiotic supplements in individuals with a higher P/B ratio. In conclusion, this study suggested the beneficial effects of synbiotic supplementation on immune parameters, which were correlated with synbiotics-induced microbial changes and modified by microbial enterotypes. These findings provided direct evidence supporting the personalized supplementation of synbiotics for immunomodulation.
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Effect of Lacticaseibacillus paracasei N1115 on Immunomodulatory and Gut Microbial Composition in Young Children: A Randomized, Placebo-Controlled Study.
Li, P, Ren, Z, Zhou, J, Zhao, A, Wang, S, Xun, Y, Jiang, H, Wang, P, Yuan, Q, Zhang, Y
Nutrients. 2023;15(8)
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Cesarean section (C-section) is one of the most common obstetrical procedures, and China is among the countries with the highest C-section rates in the world. Lactobacillus is one of the well-known and most studied probiotics and has a broad distribution in the human oral cavity, genitourinary tract, gastrointestinal tract, and milk. The aim of this study was to investigate the efficacy of Lp N1115 as a probiotic on immunomodulatory and gut microbial composition in Chinese infants and toddlers born by C-section. This study was a single-centre, randomised, triple-blind placebo-controlled trial. Healthy infants born by C-section were recruited at the age of 6–24 months and divided into two age groups: 6–12 months and 13–24 months. Infants and toddlers were randomly assigned to either the experimental group (Lp N1115 group) or the placebo-control group. Results showed that Lp N1115 can help maintain the intestinal pH of infants aged 6–24 months after C-section, improve immune function, and promote the proliferation of Lactobacillus. Furthermore, Lp N1115 could increase faecal secreted immunoglobulin A levels and, to some extent, reduce cortisol levels in infants and children. Authors conclude that the beneficial effects of Lp N1115 on gut development were more obvious in 6–12-month-old infants.
Abstract
Lactobacillus paracasei N1115 (Lp N1115) was isolated from fermented milk products. The administration of Lp N1115 is safe and well tolerated in Chinese children, but its effectiveness among young Chinese children is still unclear. To investigate the efficacy of Lp N1115 as a probiotic to enhance gut development in Chinese infants and toddlers born by cesarean section, 109 healthy and cesarean-delivered infants aged 6-24 months were recruited for a 12-week randomized, placebo-controlled trial, with 101 finally completing the study. Saliva and stool samples were collected and detected at weeks 0, 4, 8, and 12 of the intervention. Statistical analyses were performed by using a per-protocol (PP) approach. After 12 weeks of intervention, the fecal pH in the control group increased (p = 0.003), while the fecal pH in the experimental group did not change. Salivary cortisol decreased from baseline in the experimental group (p = 0.023), while the control group showed little change. In addition, Lp N1115 increased the fecal sIgA content of infants aged 6-12 months (p = 0.044) but had no obvious effect on fecal calprotectin and saliva sIgA. At week 4, the increase in Lactobacillus relative to baseline was higher in the experimental group than in the control group (p = 0.019). Further analysis showed a trend toward a higher detection rate of Lactobacillus in the experimental group than in the control group (p = 0.039). In conclusion, Lp N1115 was able to enhance the content of Lactobacillus and maintain fecal pH levels. Its beneficial effects on gut development were more obvious in 6-12-month-old infants.
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The Effects of Black Tea Consumption on Intestinal Microflora-A Randomized Single-Blind Parallel-Group, Placebo-Controlled Study.
Tomioka, R, Tanaka, Y, Suzuki, M, Ebihara, S
Journal of nutritional science and vitaminology. 2023;69(5):326-339
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Tea from the leaves of the tea plant (Camelia sinensis) is consumed around the world. Tea has many health benefits, and in part, this is due to its rich content in compounds classed as polyphenols. Through the fermentation process, black tea is particularly high in polyphenols. Previous studies around respiratory infections indicated that regular consumption of black tea appeared to improve immune defence mechanisms that protect mucous membranes, called mucosal immunity. As this mucosal immunity is closely influenced by gut bacteria, the authors speculated whether the previously seen impact of improved mucosal immunity is related to the ability of black tea to also modulate bacteria in the gut. A previously run randomised single-blinded, placebo-controlled trial with 72 Japanese participants who consumed three cups of black tea (2g) or a placebo of barley tea for 12 weeks provided the data for this study. Data gathered included gut flora analysis, short-chain fatty acids (SCFAs) levels - fats that play a role in maintaining gut health, and saliva IgA (SIgA) concentrations - which are antibodies made in the lymph tissue of the gut. The results showed that black tea consumption led to a significant increase in the abundance of Prevotella bacteria, which mediate SCFA production and are involved in normalising immune function. Furthermore, tea increased butyrate-producing bacteria. Butyrate is associated with improved barrier function of the gut walls but also helps to manage pathogens and immune responses. Black tea consumption also increased salivary SIgA concentration - a type of antibody on the mucous membranes that prevents pathogens from entering the body -, and a decrease in stool acetic acid concentration, which may be due to the increase in butyrate-producing bacteria which use acetic acid to make butyrate. Notably, participants with low salivary SIgA levels at the start had a more pronounced positive change in total bacteria, after consuming black tea compared to the placebo group. The authors concluded that regular consumption of black tea may help to improve mucosal immunity by increasing the abundance of beneficial bacteria in the gut.
Abstract
We previously reported that black tea consumption for 12 wk reduced the risk of acute upper respiratory tract inflammation, and improved secretory capacity in individuals with low salivary SIgA levels (Tanaka Y et al. 2021. Jpn Pharmacol Ther 49: 273-288). These results suggested that habitual black tea consumption improves mucosal immunity. Therefore, in this study we evaluated the effect of black tea intake on gut microbiota, which is known to be involved in mucosal immunity, by analyzing the bacterial flora and the short-chain fatty acids (SCFAs) concentration of feces collected during the above clinical study. The clinical design was a randomized, single-blind, parallel-group, placebo-controlled study with 72 healthy Japanese adult males and females, who consumed three cups of black tea (Black Tea Polymerized Polyphenols 76.2 mg per day) or placebo per day for 12 wk. In all subjects intake of black tea significantly increased abundance of Prevotella and decreased fecal acetic acid concentration. Particularly in the subjects with low salivary SIgA levels, the change over time of total bacteria, Prevotella, and butyrate-producing bacteria, which are involved in normalizing immune function, were higher in the black tea group than in the placebo group. In subjects with low abundance of Flavonifractor plautii a butyrate-producing bacteria, black tea consumption significantly increased salivary SIgA concentration and the absolute number of Flavonifractor plautii. In conclusion, our results suggest that improvement of mucosal immunity via an increase in butyrate-producing bacteria in the gut may partly contribute to the suppressive effect of black tea consumption on acute upper respiratory tract inflammation observed in our previous report.