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Gut microbiota modulate distal symmetric polyneuropathy in patients with diabetes.
Yang, J, Yang, X, Wu, G, Huang, F, Shi, X, Wei, W, Zhang, Y, Zhang, H, Cheng, L, Yu, L, et al
Cell metabolism. 2023;35(9):1548-1562.e7
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Distal symmetric polyneuropathy (DSPN) is the most common complication associated with diabetes, which can lead to pain, numbness, and weakness or tingling in the limbs or parts of the body. There are no cures for DSPN only drugs to manage symptoms, highlighting a need for further research. Recently it has been shown that the gut microbiota of individuals with DSPN differs to that of healthy individuals, but it is unclear as to the significance of this. This randomised control trial aimed to determine the effect of transplanting faecal microbiota from healthy individuals into those with DSPN. The results showed that DSPN was associated with a decreased abundance of beneficial gut bacteria and an increased abundance of pathogenic bacteria. Furthermore, compared to placebo, DSPN was alleviated in all 22 patients who received a faecal microbiota transplant from healthy subjects. There was an increase in gut microbiota associated with the production of beneficial short chain fatty acids and a decrease in toxin production. It was concluded that dysbiosis in the gut microbiota contributes to DSPN, which can be alleviated by faecal microbial transplant from healthy individuals. This study could be used by healthcare professionals to understand that the gut microbiota has an important role in DSPN. Further larger studies would be warranted before recommending faecal microbial transplant to individuals with this disorder.
Abstract
The pathogenic mechanisms underlying distal symmetric polyneuropathy (DSPN), a common neuropathy in patients with diabetes mellitus (DM), are not fully understood. Here, we discover that the gut microbiota from patients with DSPN can induce a phenotype exhibiting more severe peripheral neuropathy in db/db mice. In a randomized, double-blind, and placebo-controlled trial (ChiCTR1800017257), compared to 10 patients who received placebo, DSPN was significantly alleviated in the 22 patients who received fecal microbiota transplants from healthy donors, independent of glycemic control. The gut bacterial genomes that correlated with the Toronto Clinical Scoring System (TCSS) score were organized in two competing guilds. Increased guild 1, which had higher capacity in butyrate production, and decreased guild 2, which harbored more genes in synthetic pathway of endotoxin, were associated with improved gut barrier integrity and decreased proinflammatory cytokine levels. Moreover, matched enterotype between transplants and recipients showed better therapeutic efficacy with more enriched guild 1 and suppressed guild 2. Thus, changes in these two competing guilds may play a causative role in DSPN and have the potential for therapeutic targeting.
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Sustained Diet-Induced Remission in Pediatric Crohn's Disease Is Associated With Kynurenine and Serotonin Pathways.
Ghiboub, M, Boneh, RS, Sovran, B, Wine, E, Lefèvre, A, Emond, P, Verburgt, CM, Benninga, MA, de Jonge, WJ, Van Limbergen, JE
Inflammatory bowel diseases. 2023;29(5):684-694
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Crohn’s disease (CD) is an inflammatory bowel disease associated with alterations in intestinal tryptophan metabolism, in particular with increases in metabolites of the kynurenine pathway and decreased metabolites of the serotonin pathway. The aim of this 12-week randomised clinical study was to evaluate the effect of CD exclusion diet with partial enteral nutrition (CDED+PEN) and exclusive enteral nutrition (EEN) on intestinal tryptophan metabolism (as measured in faeces) in 43 children with mild-to-moderate CD. 13 of 15 patients on CDED+PEN and 9/13 on EEN achieved remission at week 6, and 8/9 and 6/9 patients, respectively, maintained remission at 12 weeks. Some kynurenine pathway metabolites decreased and some serotonin metabolites increased, in patients who achieved induction and maintenance of remission. These changes were similar in both intervention groups. On the other hand, in patients on EEN who did not go into remission, these changes were not observed. The authors concluded that further studies are warranted to inform whether there is a causal link and to refine nutritional interventions.
Abstract
BACKGROUND Both the Crohn's disease exclusion diet combined with partial enteral nutrition (CDED+PEN) and exclusive enteral nutrition (EEN) can induce remission in mild-to-moderate pediatric Crohn's disease and are associated with a marked decrease in fecal kynurenine levels. This suggests a link between clinical outcome of dietary therapy and changes in tryptophan metabolism pathways. Here, we characterize the changes in several fecal tryptophan metabolites induced by CDED+PEN or EEN and their association with remission. METHODS A total of 21 tryptophan metabolites were quantified in fecal samples from a 12-week prospective randomized trial with CDED+PEN or EEN for induction of remission in mild to moderate pediatric Crohn's disease. Tryptophan metabolites at week 0 (W0), W6, and W12 of 73 samples were quantitatively measured by liquid chromatography coupled with triple quadrupole mass spectrometry, and data were analyzed according to clinical groups of baselines (W0), induced remission at W6, no remission, sustained remission at W12, and nonsustained remission. RESULTS Reduction in components of the kynurenine pathway, such as kynurenine and quinolinic acid, were strongly associated with induced remission with both CDED+PEN and EEN, which were maintained in sustained remission. Specific serotonin pathway metabolites, such as melatonin, N-acetylserotonin, and 5-OH-tryptophan, were significantly increased in fecal samples from patients maintaining remission at W12 with both CDED+PEN and EEN. Importantly, in samples from patients failing to sustain remission, no changes were observed. Remission induction with EEN differs from CDED+PEN, particularly the moderate effects on indole pathway metabolites. The ratios of kynurenine and melatonin and quinolinic acid and melatonin perform well as markers for sustained remission. CONCLUSIONS The reduction in specific kynurenine pathway compounds and the increase in serotonin pathway compounds are associated with diet-induced and sustained remission. Further studies are warranted to assess causality and the association of these metabolites with specific diet and lifestyle factors, affecting sustained clinical remission. We show that fecal tryptophan metabolites are associated with remission following dietary therapy in a prospective clinical trial of pediatric Crohn’s disease patients. Our study shows that reduction in some kynurenine pathway metabolites and the increase in serotonin pathway compounds are associated with diet-induced and sustained remission. These compounds may play a role in mediating the mechanism of action of dietary therapy.
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Physical Training and Healthy Diet Improved Bowel Symptoms, Quality of Life, and Fatigue in Children With Inflammatory Bowel Disease.
Scheffers, LE, Vos, IK, Utens, EMWJ, Dieleman, GC, Walet, S, Escher, JC, van den Berg, LEM
Journal of pediatric gastroenterology and nutrition. 2023;77(2):214-221
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Inflammatory bowel disease (IBD), including Crohn disease and ulcerative colitis, are chronic inflammatory diseases of the gastrointestinal tract, characterised by periods of remission and relapse of symptoms. The aim of this study was to assess the effects of a tailored lifestyle intervention on physical fitness (maximal and submaximal exercise capacity, strength, and core stability), the patient-reported outcomes (quality of life, fatigue, and fear), clinical disease activity, and nutritional status. This study was a prospective single-centre randomised semi-crossover-controlled trial. Children were randomized into group A (start exercise) or group B (start control period). Results showed improved physical fitness, quality of life, and parent-reported fatigue. Additionally, a combination of lower clinical disease activity scores accompanied by fewer IBD symptoms suggests positive effects on intestinal inflammation. Authors concluded that based on the findings of their study, children and adolescents with IBD should be motivated and supported to acquire and maintain a healthy lifestyle.
Expert Review
Conflicts of interest:
None
Take Home Message:
- IBD is a chronic inflammatory disease of the gastrointestinal tract, characterised by periods of abdominal pain, severe diarrhoea, and fatigue
- This clinical trial suggests that a 12-week program of physical training plus personalised healthy dietary advice may improve physical fitness, quality of life, and fatigue in children with IBD.
Evidence Category:
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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
A randomised semi-crossover controlled trial was conducted to investigate the impact of a 12-week lifestyle program (3 physical training sessions per week plus personalised healthy dietary advice) in children with Inflammatory Bowel Disease (IBD).
Method
- Sixteen children with a median age of 15 [IQR: 12–16]) that were diagnosed with IBD (CD, UC, or IBD-unclassified) were randomized to group A (start exercise) or group B (start control period). Group A started the intervention immediately after the first assessment and did not have a control period. Group B started after a control period (this was planned to last for 6 weeks but due to the COVID-19 lockdown extended to 6 months)
- The lifestyle intervention lasted 12 weeks and consisted of 3 physiotherapist-supervised training sessions per week, lasting 60 minutes each. In addition, all participants received a recommended caloric intake per day based on measured rest energy expenditure and a brochure regarding healthy diet in children
- Endpoints were physical fitness (maximal and submaximal exercise capacity, strength, and core stability), patient-reported outcomes (quality of life, fatigue, and fears for exercise), clinical disease activity (faecal calprotectin and disease activity scores), and nutritional status (energy balance and body composition)
- A total of 15 out of 16 participants (93%) completed the program, one patient dropped out after one training session due to motivational problems.
Results
The primary findings of this study were as follows:
- While medical treatment remained unchanged, Paediatric Crohn's Disease Activity Index decreased versus the control period (15 [3–25] vs 2.5 [0–5], P = 0.012)
- The number of patients in clinical remission increased from 5 to 12 (P < 0.001), compared to the control period
- Quality of life (IMPACT-III) improved on 4 out of 6 domains and the total score (+13 points) versus the control period including a large improvement in bowel-related symptoms, P= 0.029)
- Fecal calprotectin decreased, but not compared to the control period, mainly due to relatively large intra-patient fluctuations (400 μg/g [57.1–1662.7] vs 128 μg/g [23.8–642.3], P = 0.016)
- Parents reported an improvement in the quality of life versus the control period on the child health questionnaire and total fatigue score (PedsQoL • Multidimensional Fatigue Scale) (+14 points, P = 0.048)
- Walking distance improved after the 12-week program, compared to the control period (P = 0.001).
Conclusion
This study revealed that a 12-week physical training program and personalised dietary advice improved bowel symptoms, quality of life, and fatigue in children with IBD.
Clinical practice applications:
- The mechanism behind the anti-inflammatory effects of exercise has not been clarified
- Multiple theories have been suggested in previously published studies such as a reduced release of adipokines due to less visceral fat, increased secretion of anti-inflammatory cytokines such as interleukin (IL)-6, and reduced transient stool time
- This clinical trial demonstrated that a 12-week program of physical training sessions plus personalised healthy dietary advice resulted in improved physical fitness, quality of life, and parent-reported fatigue.
Considerations for future research:
- A sample size calculation was not provided in the study report and it is therefore assumed that the sample size of 16 children in this trial was too small to draw a definite conclusion. A larger study over a longer period is therefore needed across diverse age and ethnic population groups to draw better conclusions
- This study did not measure mucosal inflammation before and after the intervention due to the invasive nature of the procedure. It would however be useful that future research investigate this to gain more insight into the effect of lifestyle interventions on IBD.
Abstract
OBJECTIVES Physical activity programs have been suggested as adjunctive therapy in adult inflammatory bowel disease (IBD) patients. We assessed the effects of a 12-week lifestyle intervention in children with IBD. METHODS This study was a randomized semi-crossover controlled trial, investigating a 12-week lifestyle program (3 physical training sessions per week plus personalized healthy dietary advice) in children with IBD. Endpoints were physical fitness (maximal and submaximal exercise capacity, strength, and core stability), patient-reported outcomes (quality of life, fatigue, and fears for exercise), clinical disease activity (fecal calprotectin and disease activity scores), and nutritional status (energy balance and body composition). Change in maximal exercise capacity (peak VO 2 ) was the primary endpoint; all others were secondary endpoints. RESULTS Fifteen patients (median age 15 [IQR: 12-16]) completed the program. At baseline, peak VO 2 was reduced (median 73.3% [58.8-100.9] of predicted). After the 12-week program, compared to the control period, peak VO 2 did not change significantly; exercise capacity measured by 6-minute walking test and core-stability did. While medical treatment remained unchanged, Pediatric Crohn's Disease Activity Index decreased significantly versus the control period (15 [3-25] vs 2.5 [0-5], P = 0.012), and fecal calprotectin also decreased significantly but not versus the control period. Quality of life (IMPACT-III) improved on 4 out of 6 domains and total score (+13 points) versus the control period. Parents-reported quality of life on the child health questionnaire and total fatigue score (PedsQoL Multidimensional Fatigue Scale) also improved significantly versus the control period. CONCLUSIONS A 12-week lifestyle intervention improved bowel symptoms, quality of life, and fatigue in pediatric IBD patients.
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Effects of dietary fibers or probiotics on functional constipation symptoms and roles of gut microbiota: a double-blinded randomized placebo trial.
Lai, H, Li, Y, He, Y, Chen, F, Mi, B, Li, J, Xie, J, Ma, G, Yang, J, Xu, K, et al
Gut microbes. 2023;15(1):2197837
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Functional constipation is characterised by continuously difficult, incomplete, or infrequent defecation, without an organic origin. Effective intervention strategies are required to relieve the functional constipation difficulties, particularly in rapidly aging populations, such as Chinese populations. The aim of this study was to evaluate the effectiveness of three dietary fibre formulas (polydextrose, psyllium husk, and wheat bran + psyllium husk) and one probiotic supplement on the improvement of constipation symptoms among Chinese adults with functional constipation. This study was a double-blinded randomised placebo-controlled trial which enrolled 250 participants who were randomly assigned to one of the five groups. Results showed: - that daily supplement of three prebiotic formulas with dietary fibres, or a probiotic formula effectively relieved hard stool in functional constipation patients after 4 weeks intervention. - the capacity of gut microbial genera in shaping the intervention responsiveness in the improvement of bowel movement frequency, Bristol stool scale score, and degree of defecation straining. Authors conclude that the pre or probiotic interventions may modulate gut microbiota, associated with intestinal health.
Abstract
Dietary fibers/probiotics may relieve constipation via optimizing gut microbiome, yet with limited trial-based evidences. We aimed to evaluate the effects of formulas with dietary fibers or probiotics on functional constipation symptoms, and to identify modulations of gut microbiota of relevance. We conducted a 4-week double-blinded randomized placebo-controlled trial in 250 adults with functional constipation. Intervention: A: polydextrose; B: psyllium husk; C: wheat bran + psyllium husk; D: Bifidobacterium animalis subsp. lactis HN019 + Lacticaseibacillus rhamnosus HN001; Placebo: maltodextrin. Oligosaccharides were also included in group A to D. 16S rRNA sequencing was used to assess the gut microbiota at weeks 0, 2, and 4. A total of 242 participants completed the study. No time-by-group effect was observed for bowel movement frequency (BMF), Bristol stool scale score (BSS), and degree of defecation straining (DDS), while BSS showed mean increases of 0.95-1.05 in group A to D (all P < 0.05), but not significantly changed in placebo (P = 0.170), and 4-week change of BSS showed similarly superior effects of the interventions as compared placebo. Group D showed a marginal reduction in plasma 5-hydroxytryptamine. Group A resulted in a higher Bifidobacterium abundance than placebo at week 2 and 4. Fourteen genera showed intervention-specific increasing or decreasing trends continuously, among which Anaerostipes showed increasing trends in groups B and C, associated with BMF increase. Random forest models identified specific baseline microbial genera panels predicting intervention responders. In conclusion, we found that the dietary fibers or probiotics may relieve hard stool, with intervention-specific changes in gut microbiota relevant to constipation relief. Baseline gut microbiota may predispose the intervention responsiveness. ClincialTrials.gov number, NCT04667884. What is the context?Supplementation of dietary fibers, such as psyllium husk or wheat bran (10 ~ 15 g/day) may relieve constipation symptoms, but bloating and flatulence are major concerns on a high fiber intake.Functional constipation patients had alternated gut microbiota profiles, while meta-analysis suggested that multispecies probiotics may increase bowel movement frequency and relieve hard stool in functional constipation.Dietary fibers or probiotics may lead to before-after changes of gut microbiota in patients with functional constipation, but time-series continued changes of gut microbiota during the intervention are unknown.Elevation of 5-hydroxytryptamine synthesis in enterochromaffin cells may affect bowel movement. And the elevated plasma 5-hydroxytryptamine was observed in functional constipation patients.What is new? Daily supplement of three prebiotic formulas with dietary fibers (polydextrose, psyllium husk, wheat bran, together with oligosaccharides), or a probiotic formula with Bifidobacterium animalis subsp. lactis HN019 + Lacticaseibacillus rhamnosus HN001 effectively relieved hard stool in functional constipation patients after 4 weeks intervention.We identified continued increasing or decreasing gut microbial genera over the intervention. Dietary fiber – gut microbiota (Anaerostipes)—constipation relieve (bowel movement frequency) evidence axis was identified in this human trial.Probiotic supplementation marginally reduced plasma 5-hydroxytryptamine, possibly associated with changes in BMF-related gut microbial genera.Intervention-specific baseline gut microbiota well predicted the responsiveness of constipation symptom relief.What is the impact? We provided references for the dosage and duration of dietary fiber/probiotics recommendations for adults with functional constipation, and advanced the microbial genera evidences of the fibers/probiotics-microbiota-laxation theory in humans.
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Wild blueberry (poly)phenols can improve vascular function and cognitive performance in healthy older individuals: a double-blind randomized controlled trial.
Wood, E, Hein, S, Mesnage, R, Fernandes, F, Abhayaratne, N, Xu, Y, Zhang, Z, Bell, L, Williams, C, Rodriguez-Mateos, A
The American journal of clinical nutrition. 2023;117(6):1306-1319
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The risk of developing both cardiovascular and neurodegenerative diseases increases with aging. Growing evidence from epidemiological and human intervention trials indicates that (poly)phenols may have cardioprotective properties as well as the ability to improve cognitive function. The aim of this study was to investigate the effects of daily wild blueberry (WBB) (poly)phenol consumption on vascular function and cognitive performance in healthy older individuals. This study was a randomised, double-blinded, placebo-controlled parallel design study. A total of 61 healthy older individuals were recruited and randomly assigned to one of the two arms; placebo intervention or blueberry intervention group. Results showed that long-term consumption of a dietary achievable amount of WBB enhanced vascular and cognitive function in older adults. Authors conclude that gut microbiota and vascular blood flow may play important roles in mediating the cognitive benefits shown by the consumption of (poly)phenol-rich foods.
Abstract
BACKGROUND Evidence suggests that the intake of blueberry (poly)phenols is associated with improvements in vascular function and cognitive performance. Whether these cognitive effects are linked to increases in cerebral and vascular blood flow or changes in the gut microbiota is currently unknown. METHODS A double-blind, parallel randomized controlled trial was conducted in 61 healthy older individuals aged 65-80 y. Participants received either 26 g of freeze-dried wild blueberry (WBB) powder (302 mg anthocyanins) or a matched placebo (0 mg anthocyanins). Endothelial function measured by flow-mediated dilation (FMD), cognitive function, arterial stiffness, blood pressure (BP), cerebral blood flow (CBF), gut microbiome, and blood parameters were measured at baseline and 12 wk following daily consumption. Plasma and urinary (poly)phenol metabolites were analyzed using microelution solid-phase extraction coupled with liquid chromatography-mass spectrometry. RESULTS A significant increase in FMD and reduction in 24 h ambulatory systolic BP were found in the WBB group compared with the placebo group (0.86%; 95% CI: 0.56, 1.17, P < 0.001; -3.59 mmHg; 95% CI: -6.95, -0.23, P = 0.037; respectively). Enhanced immediate recall on the auditory verbal learning task, alongside better accuracy on a task-switch task was also found following WBB treatment compared with placebo (P < 0.05). Total 24 h urinary (poly)phenol excretion increased significantly in the WBB group compared with placebo. No changes in the CBF or gut microbiota composition were found. CONCLUSIONS Daily intake of WBB powder, equivalent to 178 g fresh weight, improves vascular and cognitive function and decreases 24 h ambulatory systolic BP in healthy older individuals. This suggests that WBB (poly)phenols may reduce future CVD risk in an older population and may improve episodic memory processes and executive functioning in older adults at risk for cognitive decline. Clinical Trial Registration number in clinicaltrials.gov: NCT04084457.
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Psychobiotic Lactobacillus plantarum JYLP-326 relieves anxiety, depression, and insomnia symptoms in test anxious college via modulating the gut microbiota and its metabolism.
Zhu, R, Fang, Y, Li, H, Liu, Y, Wei, J, Zhang, S, Wang, L, Fan, R, Wang, L, Li, S, et al
Frontiers in immunology. 2023;14:1158137
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Test anxiety, characterised by feelings of failure, tension, and worrying when an individual faces a vital test for promoting, occurs prevalently among college students. Lactobacillus plantarum, has become increasingly popular in reducing the severity of anxiety and depression in stressed animal models. The main aim of this study was to evaluate the psychological effects of Lactobacillus plantarum JYLP-326 (JYLP-326) on exam stress-induced behaviours like anxiety, depression, and insomnia. This study enrolled 60 anxious and 30 un-anxious undergraduates preparing for the approaching exams. Out of the 60 anxious participants, 30 were selected randomly to receive the probiotic product and the other 30 received a placebo product. The 30 un-anxious students were assigned as the healthy control group. Results demonstrated that the intervention of JYLP-326 is effective in alleviating exam stress-induced symptoms in college students. Furthermore, it also protected against exam stress-induced dysbiosis of the gut microbiota and the disturbances of faecal metabolomic. Authors conclude that the changed gut microbiota genera and faecal metabolites were closely associated with stress-related symptoms like anxiety/depression and insomnia, indicating that they might be regarded as biomarkers for diagnosing and treating stress and anxiety disorders.
Abstract
INTRODUCTION Test anxiety is a common issue among college students, which can affect their physical and psychological health. However, effective interventions or therapeutic strategies are still lacking. This study aims to evaluate the potential effects of Lactobacillus plantarum JYLP-326 on test anxious college students. METHODS Sixty anxious students were enrolled and randomly allocated to the placebo group and the probiotic group. Both groups were instructed to take placebo and JYLP-326 products twice per day for three weeks, respectively. Thirty unanxious students with no treatments were assigned to a regular control group. The anxiety, depression, and insomnia questionnaires were used to measure students' mental states at the baseline and the end of this study. 16S rRNA sequencing and untargeted metabolomics were performed to analyze the changes in the gut microbiota and fecal metabolism. RESULTS The questionnaire results suggested that JYLP-326 administration could relieve the symptoms of anxiety, depression, and insomnia in test anxious students. The gut microbiomes of the placebo group showed a significantly greater diversity index than the control group (p < 0.05). An increased abundance of Bacteroides and Roseburia at the genus level was observed in the placebo group, and the relative abundance of Prevotella and Bifidobacterium decreased. Whereas, JYLP-326 administration could partly restore the disturbed gut microbiota. Additionally, test anxiety was correlated with disordered fecal metabolomics such as a higher Ethyl sulfate and a lower Cyclohexylamine, which could be reversed after taking JYLP-326. Furthermore, the changed microbiota and fecal metabolites were significantly associated with anxiety-related symptoms. CONCLUSION The results indicate that the intervention of L. plantarum JYLP-326 could be an effective strategy to alleviate anxiety, depression, and insomnia in test anxious college students. The potential mechanism underlying this effect could be related to the regulation of gut microbiota and fecal metabolites.
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High-fiber diet ameliorates gut microbiota, serum metabolism and emotional mood in type 2 diabetes patients.
Chen, L, Liu, B, Ren, L, Du, H, Fei, C, Qian, C, Li, B, Zhang, R, Liu, H, Li, Z, et al
Frontiers in cellular and infection microbiology. 2023;13:1069954
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Accumulating studies have demonstrated that there are strong correlations between type 2 diabetes mellitus (T2DM) and gut microbiota. A nutritious diet composed of an adequate level of dietary fibres could provide enough carbohydrates for the gut microbiota to ferment, and the microbial metabolites could provide energy supply and regulate the immune function of the host. The aim of this study was to analyse the changes in gut microbiota, serum metabolism and emotional mood of patients with T2DM after consumption of a high-fibre diet. This study was a randomised, open-label, parallel-group clinical trial in T2DM patients with a 4-week treatment period. Seventeen patients clinically diagnosed with T2DM enrolled in the clinical trial and were randomly assigned into two groups: the control group (n = 8) or the intervention group (n = 9). Results showed that the high-fibre diet (compared to the control group): - improved glucose homeostasis and lipid metabolism of participants with T2DM; - decreased serum levels of inflammatory chemokines in participants with T2DM; - alleviated depression and anxiety symptoms, particularly by the uptake of more diverse carbohydrates in the diet in participants with T2DM; - enhanced the diversity of gut microbiota in the treatment group. Authors conclude that the dietary source of fibre demonstrated protective impacts on the gut ecosystem, and the alteration of the gut microbiota composition improved the glucose homeostasis in patients with T2DM.
Abstract
Previous studies have demonstrated that patients with type 2 diabetes mellitus (T2DM) often had the problems of fecal microbiota dysbiosis, and were usually accompanied with psychiatric comorbidities (such as depression and anxiety). Here, we conducted a randomized clinical study to analyze the changes in gut microbiota, serum metabolism and emotional mood of patients with T2DM after consumption of a high-fiber diet. The glucose homeostasis of participants with T2DM was improved by the high-fiber diet, and the serum metabolome, systemic inflammation and psychiatric comorbidities were also altered. The increased abundances of Lactobacillus, Bifidobacterium and Akkermansias revealed that the proportions of beneficial gut microbes were enriched by the high-fiber diet, while the abundances of Desulfovibrio, Klebsiella and other opportunistic pathogens were decreased. Therefore, the current study demonstrated that the intestinal microbiota alterations which were influenced by the high-fiber diet could improve the serum metabolism and emotional mood of patients with T2DM.
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Effect of an Exclusive Human Milk Diet on the Gut Microbiome in Preterm Infants: A Randomized Clinical Trial.
Embleton, ND, Sproat, T, Uthaya, S, Young, GR, Garg, S, Vasu, V, Masi, AC, Beck, L, Modi, N, Stewart, CJ, et al
JAMA network open. 2023;6(3):e231165
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Receipt of mother’s own breast milk (MOM) is associated with lower rates of neonatal morbidities in preterm infants and improved long-term metabolic and neurocognitive outcomes. However, many experience a shortfall in MOM supply necessitating the use of either bovine formula or pasteurised human milk. The hypothesis of this study was that gut bacterial diversity and proportions of specific bacterial taxa would differ between trial groups as part of the mechanism by which exclusive human milk diets benefits preterm infants. This study was a randomised clinical trial for which preterm infants in the first 72 hours of life (born less than 30 weeks of gestation) were recruited. Infants (n=126) were randomly assigned to standard (control) or exclusive human milk diet (intervention). Results showed that the intervention group had no overall effect on gut microbiome richness or Shannon diversity. Furthermore, Bifidobacterium relative abundance was not associated with an exclusive human milk diet. Authors conclude that their findings show that pasteurized human milk (or products derived from human milk) do not exert a major impact on gut bacteria when used in addition to MOM.
Abstract
IMPORTANCE The effect of using an exclusive human milk diet compared with one that uses bovine products in preterm infants is uncertain, but some studies demonstrate lower rates of key neonatal morbidities. A potential mediating pathway is the gut microbiome. OBJECTIVE To determine the effect of an exclusive human milk diet on gut bacterial richness, diversity, and proportions of specific taxa in preterm infants from enrollment to 34 weeks' postmenstrual age. DESIGN, SETTING, AND PARTICIPANTS In this randomized clinical trial conducted at 4 neonatal intensive care units in the United Kingdom from 2017 to 2020, microbiome analyses were blind to group. Infants less than 30 weeks' gestation who had only received own mother's milk were recruited before 72 hours of age. Statistical analysis was performed from July 2019 to September 2021. INTERVENTIONS Exclusive human milk diet using pasteurized human milk for any shortfall in mother's own milk supply and human milk-derived fortifiers (intervention) compared with bovine formula and bovine-derived fortifier (control) until 34 weeks' postmenstrual age. Fortifier commenced less than 48 hours of tolerating 150 mL/kg per day. MAIN OUTCOMES AND MEASURES Gut microbiome profile including alpha and beta diversity, and presence of specific bacterial taxa. RESULTS Of 126 preterm infants enrolled in the study, 63 were randomized to control (median [IQR] gestation: 27.0 weeks [26.0-28.1 weeks]; median [IQR] birthweight: 910 g [704-1054 g]; 32 [51%] male) and 63 were randomized to intervention (median [IQR] gestation: 27.1 weeks [25.7-28.1 weeks]; median [IQR] birthweight: 930 g [733-1095 g]; 38 [60%] male); 472 stool samples from 116 infants were analyzed. There were no differences in bacterial richness or Shannon diversity over time, or at 34 weeks between trial groups. The exclusive human milk diet group had reduced relative abundance of Lactobacillus after adjustment for confounders (coefficient estimate, 0.056; P = .03), but not after false discovery rate adjustment. There were no differences in time to full feeds, necrotizing enterocolitis, or other key neonatal morbidities. CONCLUSIONS AND RELEVANCE In this randomized clinical trial in preterm infants using human milk-derived formula and/or fortifier to enable an exclusive human milk diet, there were no effects on overall measures of gut bacterial diversity but there were effects on specific bacterial taxa previously associated with human milk receipt. These findings suggest that the clinical impact of human milk-derived products is not modulated via microbiomic mechanisms. TRIAL REGISTRATION ISRCTN trial registry identifier: ISRCTN16799022.
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The effect of vitamin D supplementation on the gut microbiome in older Australians - Results from analyses of the D-Health Trial.
Pham, H, Waterhouse, M, Rahman, S, Baxter, C, Duarte Romero, B, McLeod, DSA, Ebeling, PR, English, DR, Hartel, G, O'Connell, RL, et al
Gut microbes. 2023;15(1):2221429
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Microbiota are communities of microorganisms that co-exist with the host ecosystem in a specific environment. The term microbiome refers to the microbial genome. The aim of this study was to investigate the effect of supplementing older adults with 60,000 IU of vitamin D per month on the gut microbiome for a period of five years, using a subsample (n = 835) of participants recruited from the large population-based D-Health Trial. This study is based on a subsample from the D-Health Trial, which was a randomised, double-blind trial with two parallel arms. Participants were randomly allocated (1:1 ratio) to monthly doses of either 60,000 IU of cholecalciferol (vitamin D3) or matching placebo. Results showed that monthly doses of 60,000 IU vitamin D over 5 years did not alter the composition of the gut microbiome in a population that is largely vitamin D replete. Authors conclude that further investigation is required to examine whether non-bolus doses of vitamin D would influence the gut microbiome or whether vitamin D supplementation would be beneficial in populations with a higher prevalence of vitamin D deficiency.
Abstract
Observational studies suggest a link between vitamin D and the composition of the gut microbiome, but there is little evidence from randomized controlled trials of vitamin D supplementation. We analyzed data from the D-Health Trial, a randomized, double-blind, placebo-controlled trial. We recruited 21,315 Australians aged 60-84 y and randomized them to 60,000 IU of vitamin D3 or placebo monthly for 5 y. Stool samples were collected from a sample of 835 participants (417 in the placebo and 418 in the vitamin D group) approximately 5 y after randomization. We characterized the gut microbiome using 16S rRNA gene sequencing. We used linear regression to compare alpha diversity indices (i.e. Shannon index (primary outcome), richness, inverse Simpson index), and the ratio of Firmicutes to Bacteroidetes between the two groups. We analyzed between-sample (beta) diversity (i.e. Bray Curtis distance and UniFrac index) using principal coordinate analysis and used PERMANOVA to test for significant clustering according to randomization group. We also assessed the difference in the abundance of the 20 most abundant genera between the two groups using negative binomial regression model with adjustment for multiple testing. Approximately half the participants included in this analysis were women (mean age 69.4 y). Vitamin D supplementation did not alter the Shannon diversity index (mean 3.51 versus 3.52 in the placebo and vitamin D groups, respectively, p = 0.50). Similarly, there was little difference between the groups for other alpha diversity indices, the abundance of different genera, and the Firmicutes-to-Bacteroidetes ratio. We did not observe clustering of bacterial communities according to randomization group. In conlusion, monthly doses of 60,000 IU of vitamin D supplementation for 5 y did not alter the composition of the gut microbiome in older Australians.
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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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Plain language summary
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.