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Bifidobacterium longum subsp. longum Reduces Perceived Psychological Stress in Healthy Adults: An Exploratory Clinical Trial.
Boehme, M, Rémond-Derbez, N, Lerond, C, Lavalle, L, Keddani, S, Steinmann, M, Rytz, A, Dalile, B, Verbeke, K, Van Oudenhove, L, et al
Nutrients. 2023;15(14)
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Psychosocial stress is a common issue and one way in which nutrition may modulate the stress response is via the microbiota-gut-brain axis. This 6-week randomised, double-blind, placebo-controlled trial of 45 healthy adults with mild-to-moderate stress evaluated the effects of Bifidobacterium longum (BL) NCC3001 on psychological and physiological markers of stress and the response to an acute stress test. Outcome measures included cortisol awakening response, heart rate, heart rate variability and various questionnaires assessing stress, anxiety, depression, sleep and gastrointestinal symptoms. Compared to placebo, probiotic intake led to a significant decrease in perceived stress and an improvement in subjective sleep after 6 weeks. There was no difference in cortisol awakening response. The subjects in both groups did not experience significant gastrointestinal symptoms and scored low on anxiety and depression at baseline. In response to the acute stress test, cortisol levels were higher in the probiotic than the placebo group, whilst no clear differences were seen in heart rate and heart rate variability. Subjects in the probiotic group had a lower pain experience during the stress test whilst subjects in the placebo group had an increase in positive mood following the test. The authors conclude that these results support their hypothesis that BL NCC3001 may alleviate stress and improve sleep in adults with moderate stress levels.
Expert Review
Conflicts of interest:
None
Take Home Message:
- There is mounting evidence to suggest that nutritional interventions can influence our stress responses. One of the routes by which nutrition can influence physiological and psychological stress responses involves the microbiota– gut–brain-axis.
- This exploratory trial suggests that supplementation with Bifidobacterium longum (BL) strain NCC3001 leads to a beneficial effect on stress relief and improves subjective sleep quality in a healthy adult population reporting moderate levels of psychological stress.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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X
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, placebo-controlled, two-arm, parallel, double-blind exploratory clinical trial was conducted to investigate the effect Bifidobacterium longum (BL) strain NCC3001 on stress-related psychological and physiological parameters and acute stress in healthy adults who typically experience mild-to-moderate-levels of stress.
Method
47 Participants between the ages of 25-65 years old with mild-to-moderate psychological stress received 1x1010 CFU of Bifidobacterium longum (BL) strain NCC3001 daily or a placebo for 6 weeks.
Participants completed the Perceived Stress Scale (PSS), the Hospital Anxiety and Depression Scales (HAD-A and HADS-D), the Gastrointestinal Symptom Rating Scale (GSRA), the Pittsburgh Sleep Quality Index (PSQI) questionnaire, the Positive and Negative Affect Schedule (PANAS), the State Trait Anxiety Inventory (STAI-6), the Maastricht Acute Stress Test (MAST) and the Visual Analog Scales (VAS, which measures pain intensity) during the clinical study. The Depression, Anxiety and Stress Scale (DASS-42) questionnaire was also used to depict the progression of the participants through the study.
Faecal samples were taken at baseline and 6 weeks and awakening saliva samples were taken at baseline, 2, 4, 6 and 8 weeks. At the endpoint, 45/49 (91%) of the subjects completed the study. One participant reported an adverse event and the other withdrew without an explanation. Two participants were excluded from the full analysis.
Results
The primary outcomes were:
- After 6-week of the probiotic intervention, there was a significant decrease in perceived stress in the probiotic group (21.4%) compared to the placebo group (-10.2%), p = 0.017.
- There was a significant improvement in subjective sleep in the probiotic group compared to the placebo group (p = 0.037).
- There was a significant decrease in the positive PANAS change score from the pre-stressor stage in the probiotic group compared to the placebo group (p = 0.01).
- There were lower pain values (VAS) scores from pre-stressor to post-stressor in the probiotic group compared to the placebo group (p = 0.05).
- There was no significant difference between groups in anxiety (HADS-A) and Depression (HADS_D) scores.
Conclusion
Oral supplementation with BL NCC3001 may have beneficial effects on stress relief and improves subjective sleep quality in a healthy adult population reporting moderate levels of psychological stress.
Clinical practice applications:
- While the mechanism underlying the correlation between the microbiota and the gut-brain-axis is not fully understood, it is thought to play a critical role in the links between the microbiota, mood, stress, and brain health.
- This exploratory trial additionally supports the potential of specific probiotics being used to reduce perceived stress and improve subjective sleep quality in healthy adults.
Considerations for future research:
- Larger, powered clinical trials are needed to provide further insights into the mechanisms underlying the stress-relieving and sleep-improving effect of Bifidobacterium longum.
- Furthermore, the dosage and duration of the probiotics need further investigation in a larger healthy population.
- Comparative research is needed to help investigate the effect of different probiotic strains on stress relief and sleep quality.
Abstract
Emerging science shows that probiotic intake may impact stress and mental health. We investigated the effect of a 6-week intervention with Bifidobacterium longum (BL) NCC3001 (1 × 1010 CFU/daily) on stress-related psychological and physiological parameters in 45 healthy adults with mild-to-moderate stress using a randomized, placebo-controlled, two-arm, parallel, double-blind design. The main results showed that supplementation with the probiotic significantly reduced the perceived stress and improved the subjective sleep quality score compared to placebo. Comparing the two groups, momentary subjective assessments concomitant to the Maastricht Acute Stress Test revealed a lower amount of pain experience in the probiotic group and a higher amount of relief at the end of the procedure in the placebo group, reflected by higher scores in the positive affect state. The awakening of the salivary cortisol response was not affected by the intervention, yet the reduction observed in the salivary cortisol stress response post-intervention was higher in the placebo group than the probiotic group. Multivariate analysis further indicated that a reduction in perceived stress correlated with a reduction in anxiety, in depression, and in the cortisol awakening response after the 6-week intervention. This exploratory trial provides promising insights into BL NCC3001 to reduce perceived stress in a healthy population and supports the potential of nutritional solutions including probiotics to improve mental health.
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A randomized trial of probiotic supplementation in nurses to reduce stress and viral illness.
Slykerman, RF, Li, E
Scientific reports. 2022;12(1):14742
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Dynamic communication occurs between the gut microbiota and the central nervous system along multiple physiological pathways. Stress increases glucocorticoid production and activation of the hypothalamic–pituitary–adrenal axis, affecting immunological function and neuronal changes. The aim of this study was to investigate whether supplementation with the probiotic Lactobacillus rhamnosus HN001 could reduce symptoms of stress and anxiety and improve psychological wellbeing in nurses working during the COVID19 pandemic. This study was a large double-blind, placebo-controlled randomised trial of probiotic supplementation with two parallel arms and a ratio of allocation to probiotic or placebo of 1:1. Results showed that following the intervention, stress, anxiety, and psychological wellbeing were not significantly different between nurses supplemented with the probiotic and those who received the placebo. Furthermore, the average number of days per week that nurses reported symptoms of cold or flu-like illness did not significantly differ between the probiotic and placebo supplemented groups. Authors conclude that there weren’t significant differences in outcomes between the probiotic and placebo groups.
Abstract
Animal studies demonstrate how the gut microbiota influence psychological health and immunity to viral infections through their actions along multiple dynamic pathways in the body. Considerable interest exists in probiotics to reduce stress and illness symptoms through beneficial effects in the gut, but translating pre-clinical evidence from animal models into humans remains challenging. We conducted a large trial in nurses working during the 2020 COVID19 pandemic year to establish whether daily ingestion of the probiotic Lactobacillus rhamnosus HN001 reduced perceived stress and the number of days participants reported symptoms of a viral illness. Our results showed no significant difference in perceived stress or the average number of illness days between probiotic supplemented nurses and the placebo group. Stress and viral illness symptoms reduced during the study for all participants, a trajectory likely influenced by societal-level factors. The powerful effect of a well-managed public health response to the COVID19 pandemic and the elimination of COVID19 from the community in 2020 may have altered the trajectory of stress levels and reduced circulating viral infections making it difficult to detect any effect of probiotic supplementation. Our study highlights the challenge in controlling environmental factors in human trials.
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Stress matters: Randomized controlled trial on the effect of probiotics on neurocognition.
Papalini, S, Michels, F, Kohn, N, Wegman, J, van Hemert, S, Roelofs, K, Arias-Vasquez, A, Aarts, E
Neurobiology of stress. 2019;10:100141
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Increasing animal studies indicate the role of probiotics in regulating mood and cognition through the gut-brain axis, however in human studies evidence of this causal association is lacking. The aim of this double-blind, randomised, placebo-controlled intervention was to investigate the effects of probiotics on neurocognitive measures in 58 healthy participants. Participants were randomly assigned to either probiotic or placebo group and were tested once before and after the 28-day intervention. The neurocognitive outcomes measured included emotion reactivity, emotion regulation, cognitive control and the effects of acute stress on working memory. These were assessed through functional MRI (fMRI) and questionnaires. This study found when stress was induced, probiotic supplementation led to a significant improvement in working memory performance. Without stress, there was no causal association between neurocognitive outcomes and probiotic intake. Based on these results, the authors conclude that during challenging situations, probiotics can aid in buffering the detrimental effects of stress on cognition.
Abstract
Probiotics are microorganisms that provide health benefits when consumed. In animals, probiotics reverse gut microbiome-related alterations in depression-like symptoms, in cognition, and in hormonal stress response. However, in humans, a causal understanding of the gut-brain link in emotion and cognition is lacking. Additionally, whether the effects of probiotics on neurocognition are visible only in presence of stress, remains unclear. We investigated the effects of a multispecies probiotic (Ecologic®Barrier) on specific neurocognitive measures of emotion reactivity, emotion regulation, and cognitive control using fMRI. Critically, we also tested whether probiotics can buffer against the detrimental effects of acute stress on working memory. In a double blind, randomized, placebo-controlled, between-subjects intervention study, 58 healthy participants were tested once before and once after a 28-day intervention. Without stress induction, probiotics did not affect brain, behavioral, or related self-report measures. However, relative to placebo, the probiotics group did show a significant stress-related increase in working memory performance after supplementation. This change was associated with intervention-related neural changes in frontal cortex during cognitive control exclusively in the probiotics group. Overall, our results show neurocognitive effects of a multispecies probiotic in healthy women only under challenging situations, buffering against the detrimental effects of stress on cognition.
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Gut dysbiosis: a potential link between increased cancer risk in ageing and inflammaging.
Biragyn, A, Ferrucci, L
The Lancet. Oncology. 2018;19(6):e295-e304
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This study looks at the important role our gut bacterial and commensal microbes play in supporting immunity and potentially reducing the risk of cancer from aging. Cancer risk increases as we age and is one of the main causes of reduced life expectancy. Our gut microbiome changes continually in response to diet, lifestyle, infection, and activation of immune responses. Gut dysbiosis is characterised by a shift towards proinflammatory commensals and a reduction of beneficial microbes, which can cause impairment and leakiness of the intestinal barrier. This is thought to trigger inflammaging or rather aging in a state of continual inflammation, where the immune system is in a heightened state of activation, and the body essentially creates an environment conducive to cancer. The gut is populated by trillions of species of bacteria which work together with our immune cells. As we age the diversity and density of these beneficial bacteria reduce. Therapies which support the balance of our commensal bacteria may prove effective at reducing rates of cancer in the elderly.
Abstract
Cancer incidence substantially increases with ageing in both men and women, although the reason for this increase is unknown. In this Series paper, we propose that age-associated changes in gut commensal microbes, otherwise known as the microbiota, facilitate cancer development and growth by compromising immune fitness. Ageing is associated with a reduction in the beneficial commensal microbes, which control the expansion of pathogenic commensals and maintain the integrity of the intestinal barrier through the production of mucus and lipid metabolites, such as short-chain fatty acids. Expansion of gut dysbiosis and leakage of microbial products contributes to the chronic proinflammatory state (inflammaging), which negatively affects the immune system and impairs the removal of mutant and senescent cells, thereby enabling tumour outgrowth. Studies in animal models and the importance of commensals in cancer immunotherapy suggest that this status can be reversible. Thus, interventions that alter the composition of the gut microbiota might reduce inflammaging and rejuvenate immune functions to provide anticancer benefits in frail elderly people.
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Reversal of cognitive decline: a novel therapeutic program.
Bredesen, DE
Aging. 2014;6(9):707-17
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Alzheimer’s Disease (AD) is estimated to affect 30 million individuals globally, with projections as high as 150 million by 2050 if no effective treatment is found. This report describes a personalised, multi-modal, therapeutic programme used with 10 individuals with various degrees of cognitive decline. The goal was to optimise metabolic parameters and lifestyle factors and was personalised based on laboratory test results. 9 out of 10 of the case study patients experienced improvement in cognitive abilities, beginning within 3-6 months of starting the programme. These effects were sustained at 2.5 year follow up. The 1 patient who did not benefit had advanced AD, in comparison to the other patients with subjective or mild cognitive decline. The authors call for a more extensive trial of the therapeutic programme.
Abstract
This report describes a novel, comprehensive, and personalized therapeutic program that is based on the underlying pathogenesis of Alzheimer's disease, and which involves multiple modalities designed to achieve metabolic enhancement for neurodegeneration (MEND). The first 10 patients who have utilized this program include patients with memory loss associated with Alzheimer's disease (AD), amnestic mild cognitive impairment (aMCI), or subjective cognitive impairment (SCI). Nine of the 10 displayed subjective or objective improvement in cognition beginning within 3-6 months, with the one failure being a patient with very late stage AD. Six of the patients had had to discontinue working or were struggling with their jobs at the time of presentation, and all were able to return to work or continue working with improved performance. Improvements have been sustained, and at this time the longest patient follow-up is two and one-half years from initial treatment, with sustained and marked improvement. These results suggest that a larger, more extensive trial of this therapeutic program is warranted. The results also suggest that, at least early in the course, cognitive decline may be driven in large part by metabolic processes. Furthermore, given the failure of monotherapeutics in AD to date, the results raise the possibility that such a therapeutic system may be useful as a platform on which drugs that would fail as monotherapeutics may succeed as key components of a therapeutic system.