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Effects of a Synbiotic on Plasma Immune Activity Markers and Short-Chain Fatty Acids in Children and Adults with ADHD-A Randomized Controlled Trial.
Yang, LL, Stiernborg, M, Skott, E, Xu, J, Wu, Y, Landberg, R, Arefin, S, Kublickiene, K, Millischer, V, Nilsson, IAK, et al
Nutrients. 2023;15(5)
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Attention deficit hyperactivity disorder (ADHD) is a common childhood-onset neurodevelopmental psychiatric disorder. The core symptoms of the disorder are inattention and hyperactivity/impulsivity. The aim of this study was to explore the effects of Synbiotic 2000 on concentrations of plasma immune activity markers and short-chain fatty acids (SCFAs) in ADHD. This study is a double-blind randomised controlled trial over a period of 9-weeks. Patients (n= 248) were randomly allocated to one of the two treatments: Synbiotic 2000 or placebo. Results show that there was no statistically significant overall effect of Synbiotic 2000 compared to placebo on any analyte analysing all the paediatric and all adult participants as one group. However, age-group stratified analyses showed that plasma levels of several of the analytes were at baseline different in the children compared to in the adults. Authors conclude that Synbiotic 2000, in children with ADHD, reduces markers of intestinal and vascular inflammation, the latter in part through increasing SCFAs levels. Furthermore, they suggest that the findings warrant further studies to determine if persons with ADHD would benefit inflammation-wise from dietary intake of Synbiotic 2000 or a similar synbiotic.
Abstract
Synbiotic 2000, a pre + probiotic, reduced comorbid autistic traits and emotion dysregulation in attention deficit hyperactivity disorder (ADHD) patients. Immune activity and bacteria-derived short-chain fatty acids (SCFAs) are microbiota-gut-brain axis mediators. The aim was to investigate Synbiotic 2000 effects on plasma levels of immune activity markers and SCFAs in children and adults with ADHD. ADHD patients (n = 182) completed the 9-week intervention with Synbiotic 2000 or placebo and 156 provided blood samples. Healthy adult controls (n = 57) provided baseline samples. At baseline, adults with ADHD had higher pro-inflammatory sICAM-1 and sVCAM-1 and lower SCFA levels than controls. Children with ADHD had higher baseline sICAM-1, sVCAM-1, IL-12/IL-23p40, IL-2Rα, and lower formic, acetic, and propionic acid levels than adults with ADHD. sICAM-1, sVCAM-1, and propionic acid levels were more abnormal in children on medication. Synbiotic 2000, compared to placebo, reduced IL-12/IL-23p40 and sICAM-1 and increased propionic acid levels in children on medication. SCFAs correlated negatively with sICAM-1 and sVCAM-1. Preliminary human aortic smooth-muscle-cell experiments indicated that SCFAs protected against IL-1β-induced ICAM-1 expression. These findings suggest that treatment with Synbiotic 2000 reduces IL12/IL-23p40 and sICAM-1 and increases propionic acid levels in children with ADHD. Propionic acid, together with formic and acetic acid, may contribute to the lowering of the higher-than-normal sICAM-1 levels.
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Effect of short-term, high-dose probiotic supplementation on cognition, related brain functions and BDNF in patients with depression: a secondary analysis of a randomized controlled trial.
Schneider, E, Doll, JPK, Schweinfurth, N, Kettelhack, C, Schaub, AC, Yamanbaeva, G, Varghese, N, Mählmann, L, Brand, S, Eckert, A, et al
Journal of psychiatry & neuroscience : JPN. 2023;48(1):E23-E33
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Major depressive disorder (MDD) is often thought of as being solely a mood disorder. However, several studies have shown that sufferers can also experience decreased brain function such as memory loss and poor attention. Current therapies for MDD focus on the balancing of mood and leaves the problem of reduced brain function unattended. The gut microbiota has recently been shown to influence brain function and altered gut microbiota composition has been seen in individuals with MDD. Targeting the gut microbiota may therefore represent a novel target for MDD treatments. This secondary analysis of a randomised control trial aimed to determine whether a probiotic multistrain supplement could improve brain function in 60 individuals with depression. The results showed that probiotics improved the brain function in two different ways, the immediate recall of words, and the improvement of decreased neural function in the hippocampal part of the brain, which has been associated with MDD. It was concluded that probiotic supplementation can enhance verbal episodic memory and improve neural function associated with impaired brain function in MDD. This study could be used by healthcare professionals to understand that the health of the gut microbiota can have an influence on brain function and that probiotics may help individuals with MDD who are suffering from poorer memory.
Abstract
BACKGROUND In major depressive disorder (MDD), cognitive dysfunctions strongly contribute to functional impairments but are barely addressed in current therapies. Novel treatment strategies addressing cognitive symptoms in depression are needed. As the gut microbiota-brain axis is linked to depression and cognition, we investigated the effect of a 4-week high-dose probiotic supplementation on cognitive symptoms in depression. METHODS This randomized controlled trial included 60 patients with MDD, of whom 43 entered modified intention-to-treat analysis. A probiotic supplement or indistinguishable placebo containing maltose was administered over 31 days in addition to treatment as usual for depression. Participant scores on the Verbal Learning Memory Test (VLMT), Corsi Block Tapping Test, and both Trail Making Test versions as well as brain-derived neurotrophic factor levels were assessed at 3 different time points: before, immediately after and 4 weeks after intervention. Additionally, brain activation changes during working memory processing were investigated before and immediately after intervention. RESULTS We found a significantly improved immediate recall in the VLMT in the probiotic group immediately after intervention, and a trend for a time × group interaction considering all time points. Furthermore, we found a time × group interaction in hippocampus activation during working memory processing, revealing a remediated hippocampus function in the probiotic group. Other measures did not reveal significant changes. LIMITATIONS The modest sample size resulting from our exclusion of low-compliant cases should be considered. CONCLUSION Additional probiotic supplementation enhances verbal episodic memory and affects neural mechanisms underlying impaired cognition in MDD. The present findings support the importance of the gut microbiota-brain axis in MDD and emphasize the potential of microbiota-related regimens to treat cognitive symptoms in depression. CLINICAL TRIAL REGISTRATION clinicaltrials.gov identifier NCT02957591.
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Psychobiotic Effects on Anxiety Are Modulated by Lifestyle Behaviors: A Randomized Placebo-Controlled Trial on Healthy Adults.
Morales-Torres, R, Carrasco-Gubernatis, C, Grasso-Cladera, A, Cosmelli, D, Parada, FJ, Palacios-García, I
Nutrients. 2023;15(7)
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The microbiota-gut-brain axis refers to the complex communication system between the human gastrointestinal tract, the micro-organisms which inhabit it, and the peripheral and central nervous systems. In recent years, human trials have linked the microbiome with specific processes that are expected to contribute to well-being. The aim of this study was to assess the effect of a psychobiotic formulation specifically on well-being, exploring the extent to which these effects might be modulated by lifestyle factors such as diet, physical activity, social connectedness, and others. This study was a four week, double-blind, randomised, placebo-controlled trial. Participants were randomised into one of two groups; placebo or probiotic group. Results showed that there were no significant effects of probiotics on a set of psychological measures of well-being. However, further analysis revealed that healthy lifestyle behaviours were significantly correlated with wellbeing across scales. Authors conclude that their findings demonstrate the need of controlling lifestyle variables as a standard practice in human microbiome research and mental health research in general.
Abstract
Psychobiotics are modulators of the Microbiota-Gut-Brain Axis (MGBA) with promising benefits to mental health. Lifestyle behaviors are established modulators of both mental health and the MGBA. This randomized placebo-controlled clinical trial (NCT04823533) on healthy adults (N = 135) tested 4 weeks of probiotic supplementation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175). We assessed effects on wellbeing, quality of life, emotional regulation, anxiety, mindfulness and interoceptive awareness. We then analyzed if lifestyle behaviors modulated probiotic effectiveness. Results showed no significant effects of probiotic intake in whole sample outcomes. Correlational analyses revealed Healthy Behaviors were significantly correlated with wellbeing across scales. Moreover, the linear mixed-effects model showed that the interaction between high scores in Healthy Behaviors and probiotic intake was the single significant predictor of positive effects on anxiety, emotional regulation, and mindfulness in post-treatment outcomes. These findings highlight the relevance of controlling for lifestyle behaviors in psychobiotic and mental health research.
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Effect of prebiotics, probiotics, synbiotics on depression: results from a meta-analysis.
Zhang, Q, Chen, B, Zhang, J, Dong, J, Ma, J, Zhang, Y, Jin, K, Lu, J
BMC psychiatry. 2023;23(1):477
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Major depressive disorder (MDD) is a mood disorder that impairs psychosocial function and quality of life. Recent studies show that prebiotics, probiotics, and synbiotics reveal a novel way to treat psychiatric disorders such as depression through the microbiota-gut-brain axis. The aim of this study was to evaluate the effectiveness of prebiotics, probiotics and synbiotics in alleviating depressive symptoms. This study was a meta-analysis of thirteen studies with a total of 786 participants who were allocated to the intervention group (n=427) and the placebo group (n=359). Results showed that the overall effects of probiotics, prebiotics and synbiotics on depressive symptoms were significantly superior to those of placebo. Additionally, biological sex was a vital factor that influenced patients’ responses to the treatment. Authors concluded that agents that manipulate gut microbiota might become a novel approach to treat patients with mild-to-moderate depression.
Abstract
Accumulating studies have shown the effects of gut microbiota management tools in improving depression. We conducted a meta-analysis to evaluate the effects of prebiotics, probiotics, and synbiotics on patients with depression. We searched six databases up to July 2022. In total, 13 randomized controlled trials (RCTs) with 786 participants were included. The overall results demonstrated that patients who received prebiotics, probiotics or synbiotics had significantly improved symptoms of depression compared with those in the placebo group. However, subgroup analysis only confirmed the significant antidepressant effects of agents that contained probiotics. In addition, patients with mild or moderate depression could both benefit from the treatment. Studies with a lower proportion of females reported stronger effects for alleviating depressive symptoms. In conclusion, agents that manipulate gut microbiota might improve mild-to-moderate depression. It is necessary to further investigate the benefits of prebiotic, probiotic and synbiotic treatments relative to antidepressants and follow up with individuals over a longer time before these therapies are implemented in clinical practice.
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Effects of probiotics on neurocognitive outcomes in infants and young children: a meta-analysis.
Lin, FL, Chen, CM, Sun, CK, Cheng, YS, Tzang, RF, Chiu, HJ, Wang, MY, Cheng, YC, Hung, KC
Frontiers in public health. 2023;11:1323511
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There have been increasing investigations into the use of probiotics for treating a variety of neurodevelopmental disorders and also for improvement of neurocognitive outcomes in preterm infants or children. The aim of this study was to provide updated evidence of the therapeutic effects of probiotics on enhancing different neurocognitive functions in infants and children as well as to identify important factors that may influence their treatment efficacies. This study was a meta-analysis of nine randomised controlled studies with 3,026 participants. Results did not show significantly better neurocognitive outcomes in those receiving probiotic treatments than those in the placebo group. However, significantly better neurocognitive development was noted in the probiotic group when focusing on studies that used probiotics for more than six months. Authors concluded that further investigations into the enhancement of therapeutic effects of probiotics on neurocognitive development is required since current evidence is still not strong enough to rule out the beneficial effects of probiotics on neurocognitive development.
Abstract
BACKGROUND Therapeutic efficacies of probiotics in improving neurocognitive functions in infants and young children remained unclear. This meta-analysis focused on different cognitive outcomes in this population. METHODS Major databases were searched electronically from inception to October 2023 to identify randomized controlled trials (RCTs) that investigated the therapeutic efficacy of probiotics in enhancing cognitive functions assessed by standardized tasks. The overall effect size was calculated as standardized mean difference (SMD) based on a random effects model. RESULTS Nine RCTs with 3,026 participants were identified. Both our primary and secondary results demonstrated no significant difference in neurocognitive outcomes between infants/children treated with probiotics and those receiving placebos. However, our subgroup analysis of studies that offered a probiotics treatment course of over six months demonstrated a significantly better neurocognitive outcome than placebos (SMD = 0.21, p = 0.03, two studies with 451 participants), but this finding was based on only two RCTs. CONCLUSION Despite lack of significant therapeutic effects of probiotics on neurocognitive outcomes, our finding of a positive impact of probiotics on neurocognitive development in those undergoing treatment for over six months may provide an important direction for further investigations into the enhancement of therapeutic effects of probiotics on neurocognitive development in infants and young children. SYSTEMATIC REVIEW REGISTRATION PROSPERO CRD42023463412.
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Effects of Lactiplantibacillus plantarum OLL2712 on Memory Function in Older Adults with Declining Memory: A Randomized Placebo-Controlled Trial.
Sakurai, K, Toshimitsu, T, Okada, E, Anzai, S, Shiraishi, I, Inamura, N, Kobayashi, S, Sashihara, T, Hisatsune, T
Nutrients. 2022;14(20)
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On the Alzheimer’s disease spectrum, which is the most common cause of dementia, the typical symptom at onset is impaired memory. As the disease progresses, other cognitive domains, such as language, visuospatial cognition, and executive function, are impaired, gradually making it impossible to maintain independence in daily life. The aim of this study was to test the protective effects of 12 weeks of supplementation with heat-treated Lactiplantibacillus OLL2712 cells on memory function in older adults. This study was a double-blind placebo-controlled trial in which participants were randomly assigned to the active or placebo group. Results showed that OLL2712 consumption had a protective effect on memory function in older adults. However, there was no significant effect of OLL2712 intake on verbal memory in either of the analyses. Furthermore, in the gut microbiota analysis, the bacterial composition of the active group showed significantly lower abundance ratios of bacterial species linked to inflammation (Lachnoclostridium, Monoglobus, and Oscillibacter). Authors conclude that continuous intake of OLL2712 may be an effective approach to protect memory function in older adults.
Abstract
The use of probiotics is expected to be an intervention in neurodegenerative conditions that cause dementia owing to their ability to modulate neuroinflammatory responses via the microbiome-gut-brain axis. Therefore, we selected Lactiplantibacillus plantarum OLL2712 (OLL2712), the optimal anti-inflammatory lactic acid bacteria strain with high IL-10-inducing activity in immune cells, and aimed to verify its protective effects on memory function in older adults. A 12-week, randomized, double-blind, placebo-controlled trial was performed with older adults over the age of 65 years with declining memory. The participants consumed either powder containing heat-treated OLL2712 cells or placebo. Memory function was assessed using a computer-assisted cognitive test, Cognitrax. Daily dietary nutrient intake was assessed using the Brief-type Self-administered Diet History Questionnaire (BDHQ). The composition of the gut microbiota was analyzed by fecal DNA extraction and 16S rDNA sequencing. Data from 78 participants who completed the entire procedure were analyzed, and significant improvements in composite memory and visual memory scores were observed in the active group, after accounting for the effect of daily nutritional intake (p = 0.044 and p = 0.021, respectively). In addition, the active group had a lower abundance ratio of Lachnoclostridium, Monoglobus, and Oscillibacter genera, which have been reported to be involved in inflammation. The present study suggests that OLL2712 ingestion has protective effects against memory function decline in older adults.
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Lactobacillus rhamnosus CNCM I-3690 decreases subjective academic stress in healthy adults: a randomized placebo-controlled trial.
Wauters, L, Van Oudenhove, L, Accarie, A, Geboers, K, Geysen, H, Toth, J, Luypaerts, A, Verbeke, K, Smokvina, T, Raes, J, et al
Gut microbes. 2022;14(1):2031695
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Previous research has shown a bidirectional relationship between the gut and psychological stress, which could be mediated by intestinal permeability followed by an immune and inflammatory response. However, the exact mechanisms of this relationship are yet to be elucidated. This randomised, double-blind, placebo-controlled trial evaluated the beneficial effects of Lactobacillus rhamnosus CNCM I-3690 on intestinal permeability and stress markers during a public speech in healthy students. Participants consumed either milk containing Lactobacillus rhamnosus CNCM I-3690 or acidified milk twice daily for four weeks to assess subjective and objective stress markers and markers of intestinal permeability. Lactobacillus rhamnosus CNCM I-3690 reduced the stress-induced hyperpermeability to mannitol and subjective stress markers (State-Trait Anxiety Inventory/ STAI). A subgroup of healthy students with stress-induced cortisol >P90 of baseline showed a reduction in perceived stress score following Lactobacillus rhamnosus CNCM I-3690 intervention. To evaluate the additional effects of Lactobacillus rhamnosus CNCM I-3690 on stress and gut health, further robust studies are needed. Healthcare professionals can use the findings of this study to understand the anxiolytic effects of Lactobacillus rhamnosus CNCM I-3690.
Abstract
Psychological stress negatively affects the intestinal barrier function in animals and humans. We aimed to study the effect of Lactobacillus rhamnosus CNCM I-3690 on intestinal permeability and stress-markers during public speech. Healthy students were randomized to L. rhamnosus-containing (test) or acidified (placebo) milk consumed twice daily for 4 weeks, with 46 subjects per treatment group. Small intestinal permeability was quantified by a 2 h urinary lactulose-mannitol ratio (LMR, primary outcome), fractional excretion of lactulose (FEL) and mannitol (FEM). Salivary cortisol, State-Trait Anxiety Inventory (STAI) and Perceived Stress scores (PSS) were collected. No between-treatment differences were found for LMR (p = .71), FEL or FEM. Within-treatment analyses showed similar LMR and FEL but a stress-induced increase of FEM with the placebo (p < .05) but not test product. Despite a similar increase in salivary cortisol, the stress-induced increase in STAI was significantly lower with the test product vs. placebo (p = .01). Moreover, a stress-preventative effect of the probiotic was found for PSS and more pronounced in subjects with high stress-induced cortisol (p = .01). While increased FEM was mediated by salivary cortisol levels, the effect of the test product on subjective stress was not mediated by changes in FEM. No serious adverse events occurred. In conclusion, we demonstrated that L. rhamnosus CNCM I-3690 prevented stress-induced hyperpermeability to mannitol. Subjective but not objective stress-markers were reduced with L. rhamnosus vs. placebo, suggesting anxiolytic effects, which were independent of barrier stabilization and attractive for the reduction of stress in both health and disease. Clinicaltrials.gov, number NCT03408691.
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Effects of Probiotics on Anxiety, Stress, Mood and Fitness of Badminton Players.
Salleh, RM, Kuan, G, Aziz, MNA, Rahim, MRA, Rahayu, T, Sulaiman, S, Kusuma, DWY, Adikari, AMGCP, Razam, MSM, Radhakrishnan, AK, et al
Nutrients. 2021;13(6)
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Exercise has been shown to improve fitness, wellbeing, and health. However, strenuous exercise may be detrimental physiologically, as well as affecting psychological health. The aim of this study was to determine the effects of daily probiotic supplementation on anxiety, stress, mood and fitness levels among competitive badminton players. This study was a randomised, placebo-controlled study. Recruited participants (n=30) were randomly divided into the probiotic group and the control group. The participants were given treatments for six weeks without altering the training schedule of the athletes. Results showed that stress and anxiety in badminton players could be alleviated with the daily consumption of probiotics for six weeks. Additionally, probiotics supplementation increased aerobic capacity. Authors conclude that probiotic supplements could be beneficial for athletes to enhance their mental state and physical performance. Thus, probiotic supplementation that may influence the regulation of pathways (neuro-endocrine) and mechanism of action in response to physical and psychological stressors encountered by badminton players should further studied.
Abstract
BACKGROUND Reports of probiotic consumption on athletes' performance are debatable due to their equivocal results. There is a need for more evidence on the effects of probiotic intake on psychological state and fitness level. Thus, this study determined the effects of daily probiotic consumption on competitive anxiety, perceived stress and mood among university badminton players, besides their fitness like aerobic capacity, strength, speed, leg power and agility. METHODS Thirty university badminton players aged from 19 to 22 years old were randomly divided equally into two groups, where the probiotic group (PG; n = 15) received a drink that contained Lactobacillus casei Shirota (3 × 1010 CFU) and placebo group (CG; n = 15) a placebo drink for six weeks. Anxiety, stress and mood levels were determined using the CSAI-2R, PSS and BRUMS questionnaires, respectively. Fitness levels were measured using by subjecting the players to 20-m shuttle runs (aerobic capacity), handgrips (muscular strength), vertical jumps (leg power), 40-m dash (speed) and T-test (agility). The Student's t-test (p < 0.05) was used to determine the differences between PG and CG players. RESULTS After six weeks, the anxiety and stress levels of PG players significantly decreased by 16% (p < 0.001) and 20% (p < 0.001), respectively, but there were no significant changes detected in CG players. Supplementation of probiotics also improved aerobic capacity in PG players by 5.9% (p < 0.001) but did not influence the speed, strength, leg power and agility. CONCLUSIONS Probiotics supplementation showed improved aerobic capacity and relieve anxiety and stress. However, further studies need to be carried out to determine the mechanisms through which probiotic intake produces these effects.
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Evolution of the Human Diet and Its Impact on Gut Microbiota, Immune Responses, and Brain Health.
González Olmo, BM, Butler, MJ, Barrientos, RM
Nutrients. 2021;13(1)
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One explanation for the increased prevalence in chronic disease and mental illness is from the evolutionary perspective. This suggests the rapid shift in diet towards processed foods in the past 200 years has not allowed for sufficient adaptation of the gut microbiome. The gut microbiome plays an important role in the digestive, immune and nervous systems via the gut-brain axis, and may be a key factor in modulating inflammation and disease. The aim of this review is to discuss how what we eat affects the immune system and impacts our brain health. The literature currently shows significant associations between the Western diet and its impact on the health of the gut microbiome and the brain. Increased intake of saturated fats, refined carbohydrates and sugar, coupled with a reduction in fiber, negatively impacts the digestive system and elicits an immune response. This response can lead to neuroinflammation, which is now found to be associated with deficits in learning and memory, as well as increased rates of neurodegenerative disease and depression. Based on the existing literature, the authors conclude the human gut microbiome has not had sufficient time to adapt to many modern foods, thus leading to inflammation and disease. The authors recommend that a diet composed of natural whole foods with minimal processing can help prevent and alleviate some of the burden caused by chronic disease, and suggest future studies focus on improving techniques to evaluate neuroinflammation in humans.
Abstract
The relatively rapid shift from consuming preagricultural wild foods for thousands of years, to consuming postindustrial semi-processed and ultra-processed foods endemic of the Western world less than 200 years ago did not allow for evolutionary adaptation of the commensal microbial species that inhabit the human gastrointestinal (GI) tract, and this has significantly impacted gut health. The human gut microbiota, the diverse and dynamic population of microbes, has been demonstrated to have extensive and important interactions with the digestive, immune, and nervous systems. Western diet-induced dysbiosis of the gut microbiota has been shown to negatively impact human digestive physiology, to have pathogenic effects on the immune system, and, in turn, cause exaggerated neuroinflammation. Given the tremendous amount of evidence linking neuroinflammation with neural dysfunction, it is no surprise that the Western diet has been implicated in the development of many diseases and disorders of the brain, including memory impairments, neurodegenerative disorders, and depression. In this review, we discuss each of these concepts to understand how what we eat can lead to cognitive and psychiatric diseases.
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Exploring the Role and Potential of Probiotics in the Field of Mental Health: Major Depressive Disorder.
Johnson, D, Thurairajasingam, S, Letchumanan, V, Chan, KG, Lee, LH
Nutrients. 2021;13(5)
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A bi-directional communication between the brain and the microbiome of the gut may exist, known as the microbiome-gut-brain axis (MGBA). The role of this and the use of probiotics in relation to many psychiatric and neurological disorders is being increasingly researched. This review aimed to summarise the research on the use of probiotics for the treatment of mental health disorders and major depressive disorder (MDD). Probiotics and their use were summarised concluding that they have a diverse range of health benefits due to their anti-inflammatory, antipathogenic and antimicrobial actions. Imbalances in the four major phyla of gut bacteria; Bacteroidetes, Firmicutes, Proteobacteria and Actinobacteria may have a major role in the development of MDD. Probiotics may have several mechanisms through which they benefit MDD and decreased inflammation in the brain, increased production of chemicals involved in brain signalling and decreased stress hormones, were all implicated. It was concluded that probiotics have mental health benefits, however gaps in the evidence from studies needs to be addressed. This study could be used by healthcare professionals to understand the role of probiotics in the treatment of mental health disorders and in particular MDD.
Abstract
The field of probiotic has been exponentially expanding over the recent decades with a more therapeutic-centered research. Probiotics mediated microbiota modulation within the microbiota-gut-brain axis (MGBA) have been proven to be beneficial in various health domains through pre-clinical and clinical studies. In the context of mental health, although probiotic research is still in its infancy stage, the promising role and potential of probiotics in various mental disorders demonstrated via in-vivo and in-vitro studies have laid a strong foundation for translating preclinical models to humans. The exploration of the therapeutic role and potential of probiotics in major depressive disorder (MDD) is an extremely noteworthy field of research. The possible etio-pathological mechanisms of depression involving inflammation, neurotransmitters, the hypothalamic-pituitary-adrenal (HPA) axis and epigenetic mechanisms potentially benefit from probiotic intervention. Probiotics, both as an adjunct to antidepressants or a stand-alone intervention, have a beneficial role and potential in mitigating anti-depressive effects, and confers some advantages compared to conventional treatments of depression using anti-depressants.