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Effect of probiotics or prebiotics on thyroid function: A meta-analysis of eight randomized controlled trials.
Shu, Q, Kang, C, Li, J, Hou, Z, Xiong, M, Wang, X, Peng, H
PloS one. 2024;19(1):e0296733
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The gut microbiome is thought to play a role in thyroid disorders, mediated by regulating iodine uptake, degradation and enterohepatic cycling of thyroid hormones, and differences in microbiome composition between patients with thyroid disorders and healthy individuals have been observed. The aim of this systematic review and meta-analysis was to evaluate the effect of pro-, pre- and synbiotics on thyroid function (thyroid stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3) and thyroid stimulating hormone receptor antibody (TRAb)) in patients with and without thyroid disorders. 8 randomised controlled trials including 367 participants were included in the review and meta-analysis. Neither pro-, pre- nor synbiotics had a significant effect on TSH, fT4 or fT3 but pre- and probiotics lead to a significant reduction in TRAb in patients with Graves’ disease.
Abstract
BACKGROUND Microbiome-directed therapies are increasingly utilized to optimize thyroid function in both healthy individuals and those with thyroid disorders. However, recent doubts have been raised regarding the efficacy of probiotics, prebiotics, and synbiotics in improving thyroid function. This systematic review aimed to investigate the potential relationship between probiotics/prebiotics and thyroid function by analyzing the impact on thyroid hormone levels. METHODS We conducted a comprehensive systematic review and meta-analysis of randomized controlled trials that investigated the effects of probiotics, prebiotics, and synbiotics on free triiodothyronine (fT3), free thyroxine (fT4), thyroid stimulating hormone (TSH), and thyroid stimulating hormone receptor antibody (TRAb) levels. We searched for articles from PubMed, Scopus, Web of Science, and Embase up until April 1st, 2023, without any language restriction. Quantitative data analysis was performed using a random-effects model, with standardized mean difference (SMD) and 95% confidence interval as summary statistics. The methods and results were reported according to the PRISMA2020 statement. RESULTS A total of eight articles were included in this review. The meta-analysis showed no significant alterations in TSH (SMD: -0.01, 95% CI: -0.21, 0.20, P = 0.93; I2: 0.00%), fT4 (SMD: 0.04, 95% CI: -0.29, 0.21, P = 0.73; I2: 0.00%) or fT3 (SMD: 0.45, 95% CI: -0.14, 1.03, P = 0.43; I2: 78.00%), while a significant reduction in TRAb levels was observed (SMD: -0.85, 95% CI: -1.54, -0.15, P = 0.02; I2: 18.00%) following probiotics/prebiotics supplementation. No indication of publication bias was found. CONCLUSIONS Probiotics/prebiotics supplementation does not influence thyroid hormone levels, but may modestly reduce TRAb levels in patients with Graves' disease.
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Multispecies probiotic administration reduces emotional salience and improves mood in subjects with moderate depression: a randomised, double-blind, placebo-controlled study.
Baião, R, Capitão, LP, Higgins, C, Browning, M, Harmer, CJ, Burnet, PWJ
Psychological medicine. 2023;53(8):3437-3447
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Gut microbiota may be able to augment an individual’s mood, brain processing and cognition. Supplements containing live bacteria or a diet high in fibre which act as a substrate for beneficial gut bacteria may be of benefit to individuals with depression or mental illness. This 4-week randomised control trial aimed to determine the effect of a probiotic containing several different gut bacteria species on emotional processing and cognition in people with mild to moderate depression. The results showed that compared to placebo, probiotic intake increased empathy with others and improved some but not all aspects of cognition. Probiotic intake did not affect biological measures of stress but did improve feelings of depression. It was concluded that multispecies probiotics may change the emotional processing of people with depression. This study could be used by healthcare professionals to understand that the use of probiotics may be a good option to reduce the risk of people with mild to moderate depression developing a major depressive disorder.
Abstract
BACKGROUND The potential antidepressant properties of probiotics have been suggested, but their influence on the emotional processes that may underlie this effect is unclear. METHODS Depressed volunteers (n = 71) were recruited into a randomised double-blind, placebo-controlled study to explore the effects of a daily, 4-week intake of a multispecies probiotic or placebo on emotional processing and cognition. Mood, anxiety, positive and negative affect, sleep, salivary cortisol and serum C-reactive peptide (CRP) were assessed before and after supplementation. RESULTS Compared with placebo, probiotic intake increased accuracy at identifying faces expressing all emotions (+12%, p < 0.05, total n = 51) and vigilance to neutral faces (mean difference between groups = 12.28 ms ± 6.1, p < 0.05, total n = 51). Probiotic supplementation also reduced reward learning (-9%, p < 0.05, total n = 51), and interference word recall on the auditory verbal learning task (-18%, p < 0.05, total n = 50), but did not affect other aspects of cognitive performance. Although actigraphy revealed a significant group × night-time activity interaction, follow up analysis was not significant (p = 0.094). Supplementation did not alter salivary cortisol or circulating CRP concentrations. Probiotic intake significantly reduced (-50% from baseline, p < 0.05, n = 35) depression scores on the Patient Health Questionnaire-9, but these did not correlate with the changes in emotional processing. CONCLUSIONS The impartiality to positive and negative emotional stimuli or reward after probiotic supplementation have not been observed with conventional antidepressant therapies. Further studies are required to elucidate the significance of these changes with regard to the mood-improving action of the current probiotic.
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Safety and Tolerability of SER-109 as an Investigational Microbiome Therapeutic in Adults With Recurrent Clostridioides difficile Infection: A Phase 3, Open-Label, Single-Arm Trial.
Sims, MD, Khanna, S, Feuerstadt, P, Louie, TJ, Kelly, CR, Huang, ES, Hohmann, EL, Wang, EEL, Oneto, C, Cohen, SH, et al
JAMA network open. 2023;6(2):e2255758
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Clostridioides difficile infection (CDI) is most commonly caused by treatment with broad-spectrum antibiotics. Antibiotic treatment of CDI is generally successful but recurrences of CDI occur in 15-25% of patients after the first episode, and up to 40% of patients with a previous recurrence. This is thought to be due to persistent microbiome disruption, including a depletion of Firmicutes bacteria. The aim of this single-arm, open-label trial was to evaluate the safety and effectiveness of an investigational, microbiome therapeutic composed of purified Firmicutes spores (SER-109) to prevent CDI recurrences. 263 patients were enrolled in the study and received SER-109 on 3 consecutive days, started within 4 days of completion of antibiotic treatment for CDI recurrence. Follow-up was 24 weeks. Most patients were aged 65 years or older and had a high prevalence of comorbidities. There were no reports of serious adverse events which were considered related to SER-109. By week 24, 36 patients (13.7%) had experienced a CDI recurrence. This was independent of demographics, type of antibiotic treatment and number of prior recurrences. The authors concluded that the data suggest a role of SER-109 in the management of recurrent CDI.
Abstract
IMPORTANCE A safe and effective treatment for recurrent Clostridioides difficile infection (CDI) is urgently needed. Antibiotics kill toxin-producing bacteria but do not repair the disrupted microbiome, which promotes spore germination and infection recurrence. OBJECTIVES To evaluate the safety and rate of CDI recurrence after administration of investigational microbiome therapeutic SER-109 through 24 weeks. DESIGN, SETTING, AND PARTICIPANTS This phase 3, single-arm, open-label trial (ECOSPOR IV) was conducted at 72 US and Canadian outpatient sites from October 2017 to April 2022. Adults aged 18 years or older with recurrent CDI were enrolled in 2 cohorts: (1) rollover patients from the ECOSPOR III trial who had CDI recurrence diagnosed by toxin enzyme immunoassay (EIA) and (2) patients with at least 1 CDI recurrence (diagnosed by polymerase chain reaction [PCR] or toxin EIA), inclusive of their acute infection at study entry. INTERVENTIONS SER-109 given orally as 4 capsules daily for 3 days following symptom resolution after antibiotic treatment for CDI. MAIN OUTCOMES AND MEASURES The main outcomes were safety, measured as the rate of treatment-emergent adverse events (TEAEs) in all patients receiving any amount of SER-109, and cumulative rates of recurrent CDI (toxin-positive diarrhea requiring treatment) through week 24 in the intent-to-treat population. RESULTS Of 351 patients screened, 263 were enrolled (180 [68.4%] female; mean [SD] age, 64.0 [15.7] years); 29 were in cohort 1 and 234 in cohort 2. Seventy-seven patients (29.3%) were enrolled with their first CDI recurrence. Overall, 141 patients (53.6%) had TEAEs, which were mostly mild to moderate and gastrointestinal. There were 8 deaths (3.0%) and 33 patients (12.5%) with serious TEAEs; none were considered treatment related by the investigators. Overall, 23 patients (8.7%; 95% CI, 5.6%-12.8%) had recurrent CDI at week 8 (4 of 29 [13.8%; 95% CI, 3.9%-31.7%] in cohort 1 and 19 of 234 [8.1%; 95% CI, 5.0%-12.4%] in cohort 2), and recurrent CDI rates remained low through 24 weeks (36 patients [13.7%; 95% CI, 9.8%-18.4%]). At week 8, recurrent CDI rates in patients with a first recurrence were similarly low (5 of 77 [6.5%; 95% CI, 2.1%-14.5%]) as in patients with 2 or more recurrences (18 of 186 [9.7%; 95% CI, 5.8%-14.9%]). Analyses by select baseline characteristics showed consistently low recurrent CDI rates in patients younger than 65 years vs 65 years or older (5 of 126 [4.0%; 95% CI, 1.3%-9.0%] vs 18 of 137 [13.1%; 95% CI, 8.0%-20.0%]) and patients enrolled based on positive PCR results (3 of 69 [4.3%; 95% CI, 0.9%-12.2%]) vs those with positive toxin EIA results (20 of 192 [10.4%; 95% CI, 6.5%-15.6%]). CONCLUSIONS AND RELEVANCE In this trial, oral SER-109 was well tolerated in a patient population with recurrent CDI and prevalent comorbidities. The rate of recurrent CDI was low regardless of the number of prior recurrences, demographics, or diagnostic approach, supporting the beneficial impact of SER-109 for patients with CDI. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT03183141.
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Acceptability, Tolerability, and Estimates of Putative Treatment Effects of Probiotics as Adjunctive Treatment in Patients With Depression: A Randomized Clinical Trial.
Nikolova, VL, Cleare, AJ, Young, AH, Stone, JM
JAMA psychiatry. 2023;80(8):842-847
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About 60% of patients with major depressive disorder (MDD) do not fully respond to anti-depressant treatments. The microbiota-gut-brain axis is thought to be involved in the development of MDD, making the microbiome a promising target for new treatments. The aim of this double-blind, randomised, placebo-controlled trial, including 50 adult patients with major depressive disorder, was to evaluate the tolerability, acceptability and efficacy of a multi-strain probiotic supplement for 8 weeks as an adjunctive to antidepressant drugs. There were no serious adverse events; all reported non-serious events were of gastrointestinal nature and more common in the probiotic group (it was not reported whether the difference was statistically significant). A high adherence rate of 97.2% suggests a high level of acceptability. Depressive mood symptoms improved significantly more in the probiotic group. Greater improvements in anxiety in the probiotic were also seen in some, but not all anxiety scales. The authors concluded that a multi-strain probiotic supplement is a promising adjunct to anti-depressant treatment in patients with MDD, with high tolerability and acceptability.
Abstract
IMPORTANCE The microbiota-gut-brain axis is a promising target for novel treatments for mood disorders, such as probiotics. However, few clinical trials have been conducted, and further safety and efficacy data are needed to support this treatment approach. OBJECTIVE To provide acceptability and tolerability data and estimates of intervention effect size for probiotics as adjunctive treatment for patients with major depressive disorder (MDD). DESIGN, SETTING, AND PARTICIPANTS In this single-center, double-blind, placebo-controlled pilot randomized clinical trial, adults aged 18 to 55 years with MDD taking antidepressant medication but having an incomplete response were studied. A random sample was recruited from primary and secondary care services and general advertising in London, United Kingdom. Data were collected between September 2019 and May 2022 and analyzed between July and September 2022. INTERVENTION Multistrain probiotic (8 billion colony-forming units per day) or placebo daily for 8 weeks added to ongoing antidepressant medication. MAIN OUTCOMES AND MEASURES The pilot outcomes of the trial were retention, acceptability, tolerability, and estimates of putative treatment effect on clinical symptoms (depression: Hamilton Depression Rating Scale [HAMD-17] and Inventory of Depressive Symptomatology [IDS] scores; anxiety: Hamilton Anxiety Rating Scale [HAMA] and General Anxiety Disorder [GAD-7] scores) to be used as indicators for a definitive trial. RESULTS Of 50 included participants, 49 received the intervention and were included in intent-to-treat analyses; of these, 39 (80%) were female, and the mean (SD) age was 31.7 (9.8) years. A total of 24 were randomized to probiotic and 25 to placebo. Attrition was 8% (1 in the probiotic group and 3 in the placebo group), adherence was 97.2%, and there were no serious adverse reactions. For the probiotic group, mean (SD) HAMD-17 scores at weeks 4 and 8 were 11.00 (5.13) and 8.83 (4.28), respectively; IDS, 30.17 (11.98) and 25.04 (11.68); HAMA, 11.71 (5.86) and 8.17 (4.68); and GAD-7, 7.78 (4.12) and 7.63 (4.77). For the placebo group, mean (SD) HAMD-17 scores at weeks 4 and 8 were 14.04 (3.70) and 11.09 (3.22), respectively; IDS, 33.82 (9.26) and 29.64 (9.31); HAMA, 14.70 (5.47) and 10.95 (4.48); and GAD-7, 10.91 (5.32) and 9.48 (5.18). Standardized effect sizes (SES) from linear mixed models demonstrated that the probiotic group attained greater improvements in depressive symptoms according to HAMD-17 scores (week 4: SES, 0.70; 95% CI, 0.01-0.98) and IDS Self Report scores (week 8: SES, 0.64; 95% CI, 0.03-0.87) as well as greater improvements in anxiety symptoms according to HAMA scores (week 4: SES, 0.67; 95% CI, 0-0.95; week 8: SES, 0.79; 95% CI, 0.06-1.05), but not GAD-7 scores (week 4: SES, 0.57; 95% CI, -0.01 to 0.82; week 8: SES, 0.32; 95% CI, -0.19 to 0.65), compared with the placebo group. CONCLUSIONS AND RELEVANCE The acceptability, tolerability, and estimated effect sizes on key clinical outcomes are promising and encourage further investigation of probiotics as add-on treatment for people with MDD in a definitive efficacy trial. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT03893162.
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The right bug in the right place: opportunities for bacterial vaginosis treatment.
Wu, S, Hugerth, LW, Schuppe-Koistinen, I, Du, J
NPJ biofilms and microbiomes. 2022;8(1):34
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The vaginal microbiome is generally dominated by Lactobacilli bacteria. However, variations exist, and in some ethnic groups a dominance of non-Lactobacilli species is more common. Lactobacilli produce various antimicrobial substances which keep growth of other bacteria in check. Bacterial vaginosis (BV) is characterized by a disturbance of the vaginal microbe balance and deficiency of Lactobacilli, giving rise to the overgrowth of certain bacteria, such as Gardnerella, Atopobium, Megasphaera, Prevotella, and Sneathia. In some countries, BV can affect over half of the women. This review discusses the advantages and challenges of the current treatment options for BV and postulates directions for future research. The article examines the use of antibiotics, their effectiveness and difficulties in obtaining long-term remission, their negative impact on the existing vaginal microbiome, the risk of antibiotic resistance and the benefits and challenges of local antibiotic applications. Following this, the authors discussed the use of prebiotics and probiotics, possible reasons why clinical trials in the past showed mixed results, and what strains may be of particular importance in vaginal health, with L. crispatus and L. iners being of particular interest here. Considered are also factors that influence and enhance bacterial colonization. Lastly, the article summarizes some current thinking on Vaginal Microbiome Transplantation, which is the transfer of vaginal microbes and fluids from a healthy donor, what benefits they may have, the associated safety risks and legislative challenges. This review is a comprehensive summary of BV treatment options, their current evidence, efficacy and drawbacks, yielding useful information to consider in the clinical management of BV.
Abstract
Bacterial vaginosis (BV) is a condition in which the vaginal microbiome presents an overgrowth of obligate and facultative anaerobes, which disturbs the vaginal microbiome balance. BV is a common and recurring vaginal infection among women of reproductive age and is associated with adverse health outcomes and a decreased quality of life. The current recommended first-line treatment for BV is antibiotics, despite the high recurrence rate. Live biopharmaceutical products/probiotics and vaginal microbiome transplantation (VMT) have also been tested in clinical trials for BV. In this review, we discuss the advantages and challenges of current BV treatments and interventions. Furthermore, we provide our understanding of why current clinical trials with probiotics have had mixed results, which is mainly due to not administering the correct bacteria to the correct body site. Here, we propose a great opportunity for large clinical trials with probiotic strains isolated from the vaginal tract (e.g., Lactobacillus crispatus) and administered directly into the vagina after pretreatment.
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Probiotic treatment with specific lactobacilli does not improve an unfavorable vaginal microbiota prior to fertility treatment-A randomized, double-blinded, placebo-controlled trial.
Jepsen, IE, Saxtorph, MH, Englund, ALM, Petersen, KB, Wissing, MLM, Hviid, TVF, Macklon, N
Frontiers in endocrinology. 2022;13:1057022
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Efforts to improve pregnancy rates remain largely focused on enhancing the quality of the transferred embryo. However, there is increasing awareness of the potential role of the intra-uterine environment as a determinant for success. The aim of this study was to determine if lactobacilli-loaded vaginal capsules are superior to placebo in improving a vaginal microbiota reported as unfavourable to implantation in women scheduled for fertility treatment. This study is a single-centre, two-arm, double-blinded, randomised controlled study. The study enrolled women aged 18–40 years who were referred to the Fertility Clinic and whose vaginal microbiota prior to fertility treatment had been diagnosed as an unfavourable. Participants (n=77) were randomised in a 1:1 ratio to either lactobacilli-loaded vaginal capsules or placebo. Results did not show any significant effect of treatment with lactobacilli-loaded vaginal capsules on the unfavourable vaginal microbiota profile among women referred to fertility treatment. However, the study showed the highly dynamic nature of the vaginal microbiota, with a spontaneous improvement rate of 34.2% (of the patients) one to three months after the baseline sample. Authors conclude that probiotics use for the improvement of vaginal microbiota should be tempered with some caution. More studies of both the vaginal and endometrial microbiota are required to confirm the efficacy of specific vaginal probiotics before they can be considered as a therapeutic solution.
Abstract
OBJECTIVE To investigate whether treatment with proprietary lactobacilli-loaded vaginal capsules improves an unfavorable vaginal microbiome diagnosed using a commercially available test and algorithm. DESIGN A randomized, double-blinded, placebo-controlled study was conducted in 74 women prior to undergoing fertility treatment at a single university fertility clinic between April 2019 and February 2021. The women were randomly assigned in a 1:1 ratio to receive one vaginal capsule per day for 10 days containing either a culture of more than 108 CFU of Lactobacillus gasseri and more than 108 CFU Lactobacillus rhamnosus (lactobacilli group) or no active ingredient (placebo group). Vaginal swabs for microbiota analysis were taken at enrollment, after treatment and in the cycle following treatment. PARTICIPANTS AND METHODS Women aged 18-40 years who prior to fertility treatment were diagnosed with an unfavorable vaginal microbiota, characterized by either a low relative load of Lactobacillus or a high proportion of disrupting bacteria using the criteria of the IS-pro™ diagnostic system (ARTPred, Amsterdam, the Netherlands), were enrolled in the study. The primary outcome measure was the proportion of women with improvement of the vaginal microbiota after intervention. RESULTS The vaginal microbiota improved after intervention in 34.2% of all participants (lactobacilli group 28.9%, placebo group 40.0%), with no significant difference in the improvement rate between the lactobacilli and placebo groups, RR = 0.72 (95% CI 0.38-1.38). CONCLUSION This study indicates that administering vaginal probiotics may not be an effective means of modulating the vaginal microbiome for clinical purposes in an infertile population. However, a spontaneous improvement rate of 34.2% over a period of one to three months, confirming the dynamic nature of the vaginal microbiota, indicates that a strategy of postponing further IVF treatment to await microbiota improvement may be relevant in some patients, but further research is needed. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, identifier NCT03843112.
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Effects of Lactococcus lactis subsp. cremoris YRC3780 daily intake on the HPA axis response to acute psychological stress in healthy Japanese men.
Matsuura, N, Motoshima, H, Uchida, K, Yamanaka, Y
European journal of clinical nutrition. 2022;76(4):574-580
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The hypothalamic-pituitary-adrenal (HPA) axis is involved in the stress response and is linked to the microbiome through a number of possible mechanisms, including immune-related ones. Lactococcus lactis subsp. cremoris YRC3780 (YRC3780), a probiotic isolated from kefir, has been shown to have beneficial immune-modulatory properties. The aim of this double-blind, placebo-controlled trial, which included 27 healthy young men, was to assess sleep quality, mental health, HPA axis activity (salivary cortisol) and response to an acute stress test during/after 8 weeks of supplementation with YRC3780. At 8 weeks, salivary morning cortisol levels were significantly reduced in the probiotic compared to the placebo group. The effect on the stress test depended on whether or not participants were considered “cortisol-responders” or not. Improvements in sleep quality were seen at 6 weeks (but not at any other time points) in 1 out of 2 sleep questionnaires in the YRC3780 group, whilst no significant differences were observed in actigraphy-measured sleep efficiency. There were no differences in mood between groups, but significant improvements in general health in the probiotic group. Interestingly, no changes in the microbiome of the probiotic group were seen, suggesting that the observed effects may be mediated via the immune system.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Research indicates a bidirectional interaction between the gut microbiome and the central nervous system, affecting the functions of the brain and spinal cord.
- This clinical trial suggests that daily intake of Lactococcus lactis subsp. cremoris (YRC3780) may enhance the HPA axis response to acute psychological stress, potentially linked to a reduction in morning cortisol levels.
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 randomized, placebo-controlled, double-blind clinical trial was conducted to investigate the influence of Lactococcus lactis subsp. cremoris (YRC3780), isolated from kefir, on stress response, sleep quality, and mental health.
Method
Twenty-seven healthy young men, with an average age of 23.5 years, and mean body mass index of 21.5 kg/m2 , were randomly assigned to either the YRC3780 group or the placebo group. Participants were administered YRC3780 or a placebo daily for 8 weeks.
Throughout the study, participants completed assessments, including the Athens Insomnia Scale (AIS), the Pittsburgh Sleep Quality Index (PSQI), the General Health Questionnaire (GHQ-28), and the Profile of Mood States 2nd Edition-Adult Short, Total Mood Disturbance subscale (POMS 2 TMD), every 2 weeks. Additionally, diurnal rhythms of HPA axis activity were assessed every 2 weeks through saliva samples collected at 2-hour intervals during the day. At the end of the 8-week supplementation period, participants underwent the Trier Social Stress Test (TSST) to evaluate the effects of daily YRC3780 intake on the HPA axis stress response. In addition, three fecal samples were collected to analyse the gut microbiome (on the last day of baseline, and at 4 and 8 weeks).
A total of 27 out of 33 subjects (81%) completed the study, with six participants withdrawing without providing explanations.
Results
The primary findings of this study were as follows:
- At week 6 of YRC3780 supplementation, salivary cortisol levels at 2 hours and 6 hours after waking were significantly lower in the YRC3780 group compared to the placebo group (p=0.05).
- Salivary cortisol concentrations at 40 minutes after the TSST were significantly lower in the YRC3780 group (4.2 ± 4.4 nmol/L, mean ± SD) than in the placebo group (7.6 ± 4.7 nmol/L) (p=0.043).
- AIS scores at 6 weeks and GHQ-28 scores at 8 weeks were significantly lower in the YRC3780 group compared to the placebo group (AIS, p=0.031; GHQ-28, p=0.038) indicating better sleep quality and a better mental state.
Conclusion:
Oral supplementation with YRC3780 may have beneficial effects on the HPA axis response to acute psychological stress, potentially associated with a decrease in morning cortisol levels. Additionally, the study suggests that the lower basal activity and stress reactivity of the HPA axis may lead to improvements in subjective sleep quality and mental health.
Clinical practice applications:
- The precise mechanisms underlying the correlation between the gut microbiota and the gut-brain axis remain incompletely understood, emphasising the need for further research.
- This clinical trial demonstrated that daily intake of YRC3780 decreased morning salivary cortisol levels at 6 and 8 weeks and reduced the salivary cortisol response to acute psychological stress.
Considerations for future research:
- Larger, adequately powered clinical trials are required to provide deeper insights into the mechanisms responsible for the stress-reducing and sleep-improving effects of Lactococcus lactis subsp. cremoris.
- Furthermore, investigations into optimal dosage and duration of probiotic supplementation are warranted for a more comprehensive understanding, particularly in diverse demographic groups.
- Comparative research is needed to explore the effects of various probiotic strains on objective stress responses.
Abstract
BACKGROUND Lactococcus lactis subsp. cremoris (YRC3780), which is isolated from kefir, has been associated with anti-allergic effects in humans. However, it remains unknown whether daily intake of YRC3780 attenuates the response to psychological stress in humans in parallel with changes to the gut microbiome. We examined the fundamental role of YRC3780 in the gut microbiome, stress response, sleep, and mental health in humans. METHODS Effects of daily intake of YRC3780 on the hypothalamic-pituitary-adrenal (HPA) axis response to acute psychological stress were investigated in a double-blind, placebo-controlled clinical trial involving 27 healthy young men (mean age and body mass index: 23.5 years and 21.5 kg/m2) who were randomly assigned to placebo (n = 13) or YRC3780 (n = 14) groups. The HPA axis response to acute psychological stress, the diurnal rhythm of HPA axis activity, and gut microbiome were assessed and compared between the two groups. RESULTS The results showed that daily intake of YRC3780 significantly lowered morning salivary cortisol levels compared with placebo. In addition, salivary cortisol levels following a social stress test significantly decreased +40 min after beginning the TSST in the YRC3780-treated group compared to placebo. There were no significant differences between the two groups in terms of actigraphy-based sleep quality, but the subjective sleep quality and mental health were significantly improved in the YRC3780-treated group compared to placebo. CONCLUSIONS Our study suggests that daily intake of YRC3780 improves the HPA axis response to acute psychological stress, which might be associated with a decrease in morning cortisol levels.
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Implications of the vaginal microbiome and potential restorative strategies on maternal health: a narrative review.
Moumne, O, Hampe, ME, Montoya-Williams, D, Carson, TL, Neu, J, Francois, M, Rhoton-Vlasak, A, Lemas, DJ
Journal of perinatal medicine. 2021;49(4):402-411
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The vaginal microbiome is a complex community of bacteria that maintains and contributes to vaginal health and works together to protect the host from disease. Lactobacilli are the predominant species in a healthy vaginal microbiome. This review sought to summarize current evidence on how changes in the vaginal microbiome composition before and throughout pregnancy influence and contribute to several health conditions. The authors investigated the role of the vaginal microbiome in fertility and in-vitro fertilization (IVF), where evidence is still conflicting, followed by conditions that can present during pregnancy such as preterm labour, gestational diabetes, and preeclampsia. In preterm labour, lower levels of Lactobacillus and its D-lactic acid secretions have been observed as a common denominator; in gestational diabetes, it remains unclear whether the changes in the vaginal microbiome associated with the condition are causative or rather a result of the condition. Little research has been done regarding preeclampsia, but initial studies indicate there may be a link between the condition and the vaginal microbiome. The authors also reviewed the evidence on methods of restoring vaginal health, including oral and vaginally applied probiotics as well as vaginal microbiome transplants (VMT) - the transfer of vaginal secretions from a healthy donor. The paper discusses the evidence on the use of oral and locally applied probiotics for the aforementioned conditions, and the promising potential of VMTs alongside the risks and regulatory challenges that come with it. This review provides a helpful summary of the current understanding of the role of the vaginal microbiome in fertility and throught pregnancy.
Abstract
The vaginal microbiome undergoes dramatic shifts before and throughout pregnancy. Although the genetic and environmental factors that regulate the vaginal microbiome have yet to be fully elucidated, high-throughput sequencing has provided an unprecedented opportunity to interrogate the vaginal microbiome as a potential source of next-generation therapeutics. Accumulating data demonstrates that vaginal health during pregnancy includes commensal bacteria such as Lactobacillus that serve to reduce pH and prevent pathogenic invasion. Vaginal microbes have been studied as contributors to several conditions occurring before and during pregnancy, and an emerging topic in women's health is finding ways to alter and restore the vaginal microbiome. Among these restorations, perhaps the most significant effect could be preterm labor (PTL) prevention. Since bacterial vaginosis (BV) is known to increase risk of PTL, and vaginal and oral probiotics are effective as supplemental treatments for BV prevention, a potential therapeutic benefit exists for pregnant women at risk of PTL. A new method of restoration, vaginal microbiome transplants (VMTs) involves transfer of one women's cervicovaginal secretions to another. New studies investigating recurrent BV will determine if VMTs can safely establish a healthy Lactobacillus-dominant vaginal microbiome. In most cases, caution must be taken in attributing a disease state and vaginal dysbiosis with a causal relationship, since the underlying reason for dysbiosis is usually unknown. This review focuses on the impact of vaginal microflora on maternal outcomes before and during pregnancy, including PTL, gestational diabetes, preeclampsia, and infertility. It then reviews the clinical evidence focused on vaginal restoration strategies, including VMTs.
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Effects of 4 weeks of Lactobacillus plantarum 299v supplementation on nutritional status, enteral nutrition tolerance, and quality of life in cancer patients receiving home enteral nutrition - a double-blind, randomized, and placebo-controlled trial.
Kaźmierczak-Siedlecka, K, Folwarski, M, Ruszkowski, J, Skonieczna-Żydecka, K, Szafrański, W, Makarewicz, W
European review for medical and pharmacological sciences. 2020;24(18):9684-9694
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Enteral nutrition (tube feeding) in cancer patients is associated with inadequate nutritional status and gastrointestinal symptoms, such as diarrhoea, nausea, vomiting, abdominal pain and flatulence which can have a negative effect on quality of life (QOL). Several factors are thought to mediate these symptoms, one of which is an inadequate composition of the gut microbiome. The aim of this double-blind, placebo-controlled trial of 25 cancer patients was to determine the effect of the probiotic Lactobacillus plantarum 299v DSM 9843 (Lp299v), 20 billion organisms per day for 4 weeks, on nutritional status, gastrointestinal tolerance and QOL. After 4 weeks, there was no difference in total serum protein, lymphocyte count, QOL, total body, fat or muscle mass between groups. Digestive symptoms improved significantly in the probiotic group, but this was not statistically different from the placebo group. The only significant benefit of Lp299v over placebo was a greater increase in serum albumin, a marker of nutritional status.
Abstract
OBJECTIVE Several human trials have confirmed that Lactobacillus plantarum 299v (Lp299v) relief the gastrointestinal symptoms observed in patients with irritable bowel syndrome, such as nausea, vomiting, and diarrhea. These symptoms are similar to those associated with home enteral nutrition and they affect nutritional status as well as patients' quality of life. The aims of this study were to determine the effect of Lp299v on nutritional status, enteral formula tolerance, and quality of life in cancer patients. PATIENTS AND METHODS The current double-blind, randomized, and placebo-controlled study included 35 cancer patients receiving home enteral nutrition. There were 2 groups of participants consuming either 2 x 10^10 CFU of Lp299v (n=21) or placebo (n=14) for 4 weeks. RESULTS An increase in the serum albumin concentration was significantly higher in the Lp299v group than in the placebo group at the endpoint (p=0.032). Moreover, the changes in the frequency of vomiting and flatulence were significantly reduced at week 4 compared to baseline in the Lp299v group (p=0.0117). The improvement of quality of life was observed in both groups; however, with no statistically significant differences between the analyzed groups (p>0.05). CONCLUSIONS We have demonstrated that administration of Lp299v in cancer patients receiving home enteral nutrition may improve laboratory parameters, predominantly the concentration of albumin, however, overall it does not have an impact on nutritional status. Lp299v may reduce the gastrointestinal symptoms related to enteral nutrition; notwithstanding, the improvement of quality of life may be the result of enteral nutrition rather than the effect of administration of Lp299v.
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Fermented Foods: Definitions and Characteristics, Impact on the Gut Microbiota and Effects on Gastrointestinal Health and Disease.
Dimidi, E, Cox, SR, Rossi, M, Whelan, K
Nutrients. 2019;11(8)
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Plain language summary
Fermented foods have grown in popularity due to their proposed health benefits but there is limited clinical evidence for the effectiveness of most fermented foods in gastrointestinal health. This review paper looks at non-dairy fermented foods which have been studied in at least one RCT: kefir, sauerkraut, natto, and sourdough bread. The health benefits are attributed to the high ratio of probiotic microorganisms, metabolites, or ability to convert compounds into active metabolites, as well as prebiotics and vitamins contained in these foods. Kimchi has the greatest evidence from epidemiological and case control studies investigating risk of gastric cancers. Different food composition of kimchi is shown to both increase and decrease risks, whilst it had no impact on H. pylori levels. There were no studies on kefir in functional bowel disorders however, it was shown to help lactose malabsorption and reduce H. pylori levels. A small RCT on Sauerkraut showed it reduced IBS severity in patients and increased in vitro activity of key liver and kidney detoxifying enzymes. There are small pockets of data that show that tempeh may influence gut microbiota in humans, and that natto may increase bifidobacterial and short-chain fatty acids in healthy volunteers. There are numerous limited cohort studies on miso and cancer risk but no studies on gastrointestinal conditions. Finally, sourdough was shown to reduce FODMAPS and be better tolerated in IBS patients, reducing bloating, nausea and discomfort. Overall, all the studies provide insufficient evidence on fermented foods and gastrointestinal health.
Abstract
Fermented foods are defined as foods or beverages produced through controlled microbial growth, and the conversion of food components through enzymatic action. In recent years, fermented foods have undergone a surge in popularity, mainly due to their proposed health benefits. The aim of this review is to define and characterise common fermented foods (kefir, kombucha, sauerkraut, tempeh, natto, miso, kimchi, sourdough bread), their mechanisms of action (including impact on the microbiota), and the evidence for effects on gastrointestinal health and disease in humans. Putative mechanisms for the impact of fermented foods on health include the potential probiotic effect of their constituent microorganisms, the fermentation-derived production of bioactive peptides, biogenic amines, and conversion of phenolic compounds to biologically active compounds, as well as the reduction of anti-nutrients. Fermented foods that have been tested in at least one randomised controlled trial (RCT) for their gastrointestinal effects were kefir, sauerkraut, natto, and sourdough bread. Despite extensive in vitro studies, there are no RCTs investigating the impact of kombucha, miso, kimchi or tempeh in gastrointestinal health. The most widely investigated fermented food is kefir, with evidence from at least one RCT suggesting beneficial effects in both lactose malabsorption and Helicobacter pylori eradication. In summary, there is very limited clinical evidence for the effectiveness of most fermented foods in gastrointestinal health and disease. Given the convincing in vitro findings, clinical high-quality trials investigating the health benefits of fermented foods are warranted.