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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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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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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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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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Consumption of 85% cocoa dark chocolate improves mood in association with gut microbial changes in healthy adults: a randomized controlled trial.
Shin, JH, Kim, CS, Cha, L, Kim, S, Lee, S, Chae, S, Chun, WY, Shin, DM
The Journal of nutritional biochemistry. 2022;99:108854
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Disturbances in a person’s mood interrupts their personal well-being and the ability to participate in social interactions, leading to physical health problems such as chronic diseases. The role of diet as a mood regulator has received a great deal of interest. Certain dietary components have been shown to reduce anxiety and depression and improve quality of life. The aim of this study was to investigate the effects of dark chocolate intake on mood in everyday life, with special emphasis on the gut-brain axis. This study is a randomized controlled trial. Participants who met the criteria for eligibility were randomly assigned to one of three groups: (1) control group (CON, n=14); 2) 85% cocoa chocolate group (DC85, n=18); and 3) 70% cocoa chocolate group (DC70, n=16). Results show that daily intake of dark chocolate significantly reduced negative affect in the DC85, but not in the DC70. Furthermore, gut microbial diversity was significantly higher in DC85 than the CON. Authors conclude that dark chocolate has prebiotic effects by restructuring the diversity and composition of the gut microbiome, which may in turn improve mood via the gut-brain axis.
Expert Review
Conflicts of interest:
None
Take Home Message:
- To highlight the potential benefits of high cocoa content dark chocolate in relation to mental states
- To promote more awareness of how dietary habits may impact emotional wellbeing
- To emphasise the importance of microbiota and the gut-brain axis regarding dietary habits.
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:
Background
The authors highlight that dark chocolate has been continually identified for its effects on mood. However, there is a dearth of evidence concerning the emotional impact of daily consumption of dark chocolate. Hence, the impact of dark chocolate consumption on daily mood, focusing on the gut-brain axis, is being investigated in this study.
Objectives
- To evaluate the correlation between the effect on emotional state after consuming dark chocolate and the gut microbiota in healthy adults
- To identify alterations in the composition and diversity of the microorganisms in the gastrointestinal tract on account of dark chocolate intake.
Study Design
A randomised controlled trial was performed at Seoul National University from July to December 2017, This involved. consumption of two types of dark chocolate (70% and 85% cocoa content). Subjects in the treatment groups were blinded although investigators and the control cohort were unblinded.
Participants
117 individuals were screened. However, 48 healthy males and females aged 20-30 years were eligible at baseline.
Interventions
- Subjects (n=16): Consumed 30g/day of 70% cocoa chocolate for 3 weeks
- Participants (n=18): Consumed 30g/day of 85% cocoa chocolate for 3 weeks
- Participants (n=14): The control group consumed no chocolate for 3 weeks.
Main Health Outcomes Measured
- Mood states were quantified via the Positive and Negative Affect Schedule in tandem with Microbiota analysis pre- and post-experiment
- Body composition analysis and dietary assessment were also conducted pre- and post-intervention
- Faecal 16S rRNA sequencing analysis of bacterial genomic DNA was conducted for the cohort who consumed 85% cocoa chocolate and the control arm to evaluate the association between the mood-altering effects of dark chocolate and the gut microbiota
- Statistical tests were performed based on intention-to-treat analysis. The Chi-squared test, Kruskal-Wallis test, one-way ANOVA, unpaired t-test and Mann-Whitney U test were employed for inter-group analysis. Spearman's correlation analysis was used to assess the association between gut microbiota composition and mood scores and P<.05 was considered statistically significant.
Results
- Daily intake of dark chocolate substantially diminished negative emotional states in the cohort consuming 85% cocoa content, but not in the 70% cocoa treatment arm
- Gut microbial diversity was substantially greater in the 85% cacao cohort than the control group (P<.05)
- Blautia obeum levels were significantly elevated and Faecalibacterium prausnitzii levels were decreased in the 85% cacao cohort than the control arm (P<.05).
- Furthermore, it was observed that changes in negative affect scores were inversely correlated with diversity and relative abundance of Blautia obeum (P<.05).
Conclusions
The observations suggest that consumption of dark chocolate with a higher cocoa content may induce prebiotic effects due to its capacity to restructure the diversity and composition of the gut microbiota. Furthermore, consuming dark chocolate with a higher cocoa might exert a positive effect on negative emotional states through the gut-brain axis.
Clinical practice applications:
- To inform practitioners of the benefits of 30g/day high (85%) cocoa chocolate consumption and its potential positive impact on mood through the gut-brain axis
- To educate clients regarding the potential benefits of daily high cocoa content chocolate consumption and its possible favourable effect on emotional states associated with gut microbiota.
Considerations for future research:
- More extensive research could investigate interventions of a longer period
- Further studies could evaluate if any difference exists between cocoa and cacao consumption and emotional states via the gut-brain axis, and the strength of any associations
- Interventions could investigate which strains of bacteria that high cocoa content dark chocolate may affect.
Abstract
Dark chocolate has long been recognized for its mood-altering properties; however, the evidence regarding the emotional effects of daily dark chocolate intake is limited. Therefore, we aimed to investigate the effects of dark chocolate intake on mood in everyday life, with special emphasis on the gut-brain axis. Two different dark chocolates (85% and 70% cocoa content) were tested in this study. In a randomized controlled trial, healthy adults (20-30 y) consumed either 30 g/d of 85% cocoa chocolate (DC85, n=18); 70% cocoa chocolate (DC70, n=16); or no chocolate (control group, CON; n=14); for 3 weeks. Mood states were measured using the Positive and Negative Affect Schedule (PANAS). Daily consumption of dark chocolate significantly reduced negative affect in DC85, but not in DC70. To assess the association between the mood-altering effects of dark chocolate and the gut microbiota, we performed fecal 16S rRNA sequencing analysis for the DC85 and CON groups. Gut microbial diversity was significantly higher in DC85 than CON (P<.05). Blautia obeum levels were significantly elevated and Faecalibacterium prausnitzii levels were reduced in DC85 compared to CON (P<.05). Furthermore, we found that the observed changes in negative affect scores were negatively correlated with diversity and relative abundance of Blautia obeum (P<.05). These findings indicate that dark chocolate exerts prebiotic effects, as evidenced by its ability to restructure the diversity and abundance of intestinal bacteria; thus, it may improve negative emotional states via the gut-brain axis.
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Effects of Fermented Milk Containing Lacticaseibacillus paracasei Strain Shirota on Constipation in Patients with Depression: A Randomized, Double-Blind, Placebo-Controlled Trial.
Zhang, X, Chen, S, Zhang, M, Ren, F, Ren, Y, Li, Y, Liu, N, Zhang, Y, Zhang, Q, Wang, R
Nutrients. 2021;13(7)
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Constipation is a common complaint among people with depression and may negatively affect their quality of life. In association with this, previous studies have shown a correlation between the reduction of Lactobacillus or Bifidobacterium strains in the gut of patients with major depressive disorder. Thus, this two-arm, parallel-design, randomised, double-blinded, placebo-controlled trial examined the effects of supplementing fermented milk with Lacticaseibacillus paracasei Strain Shirota or LcS (previously known as Lactobacillus casei strain Shirota) on constipation in people with depression. Symptoms of constipation, stool problems, and depressive symptoms improved after 9 weeks of consuming fermented milk containing LcS. The abundance of Adlercreutzia, Megasphaera, and Veillonella increased significantly in the intervention group. In contrast, the abundance of bacteria related to mental disorders such as Rikenellaceae_RC9_gut_group, Sutterella and Oscillibacter significantly decreased after the intervention. After 9 weeks of intervention with LcS, a significant reduction in serum proinflammatory cytokines such as IL-1β, IL-6, and TNF-α was observed in patients with depression. The intervention group also showed a decrease in inflammation-causing bacteria, Surrerella, which correlated with a reduction in proinflammatory cytokines. The mechanisms driving the changes in gut microbial composition, depression, and gastrointestinal symptoms after LcS intervention need to be evaluated in more robust studies. Healthcare professionals can use the results of the study to better understand how probiotics can reduce constipation and depression and improve gut microbial composition.
Abstract
Probiotics have been shown to benefit patients with constipation and depression, but whether they specifically alleviate constipation in patients with depression remains unclear. The aim of this study was to investigate the effect of Lacticaseibacillus paracasei strain Shirota (LcS), formerly Lactobacillus casei strain Shirota, on constipation in patients with depression with specific etiology and gut microbiota and on depressive regimens. Eighty-two patients with constipation were recruited. The subjects consumed 100 mL of a LcS beverage (108 CFU/mL) or placebo every day for 9 weeks. After ingesting beverages for this period, we observed no significant differences in the total patient constipation-symptom (PAC-SYM) scores in the LcS group when compared with the placebo group. However, symptoms/scores in item 7 (rectal tearing or bleeding after a bowel movement) and items 8-12 (stool symptom subscale) were more alleviated in the LcS group than in the placebo group. The Beck Depression Index (BDI) and Hamilton Depression Rating Scale (HAMD) scores were all significantly decreased, and the degree of depression was significantly improved in both the placebo and LcS groups (p < 0.05), but there was no significant difference between the groups. The LcS intervention increased the beneficial Adlercreutzia, Megasphaera and Veillonella levels and decreased the bacterial levels related to mental illness, such as Rikenellaceae_RC9_gut_group, Sutterella and Oscillibacter. Additionally, the interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) levels were significantly decreased in both the placebo and LcS groups (p < 0.05). In particular, the IL-6 levels were significantly lower in the LcS group than the placebo group after the ingestion period (p < 0.05). In conclusion, the daily consumption of LcS for 9 weeks appeared to relieve constipation and improve the potentially depressive symptoms in patients with depression and significantly decrease the IL-6 levels. In addition, the LcS supplementation also appeared to regulate the intestinal microbiota related to mental illness.
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Effects of Probiotic NVP-1704 on Mental Health and Sleep in Healthy Adults: An 8-Week Randomized, Double-Blind, Placebo-Controlled Trial.
Lee, HJ, Hong, JK, Kim, JK, Kim, DH, Jang, SW, Han, SW, Yoon, IY
Nutrients. 2021;13(8)
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Dietary changes directly alter the gut microbiome composition. A diversified gut microbiome may have therapeutic implications for mental health, and specific strains of probiotics have shown the potential to treat depression and anxiety. Several preclinical trials have found the probiotic mixture NVP-1704 to alleviate depression and anxiety in mice through modulating the gut-brain-microbiome axis. The aim of this randomised, double-blind, placebo-controlled, parallel study was to examine the efficacy and safety of NVP-1704 for the management of depression, anxiety and insomnia in healthy adults. A total of 156 healthy adults with subclinical depression, anxiety and insomnia were randomised to receive either NVP-1704 or placebo for eight weeks. Participants completed various questionnaires and biomarkers of stress and inflammation were assessed. After eight weeks, this study found that NVP-1704 to be a safe and well-tolerated probiotic with beneficial effects on depression, sleep quality, inflammation and gut microbiome composition in healthy adults. Based on this study, the authors conclude the therapeutic effects of NVP-1704 previously found in preclinical mice trials may now be translated to clinical trials. The authors suggest large, highly controlled, longitudinal human studies be conducted in the future to further confirm the benefits of probiotics on mental health and sleep.
Abstract
The human gut microbiome is closely linked to mental health and sleep. We aimed to verify the efficacy and safety of probiotic NVP-1704, a mixture of Lactobacillus reuteri NK33 and Bifidobacterium adolescentis NK98, in improving stress, depression, anxiety, and sleep disturbances, along with the measurement of some blood biomarkers. A total of 156 healthy adults with subclinical symptoms of depression, anxiety, and insomnia were retrospectively registered and randomly assigned to receive either NVP-1704 (n = 78) or a placebo (n = 78) for eight weeks. Participants completed the Stress Response Inventory, Beck's Depression and Anxiety Inventory, Pittsburg Sleep Quality Index, and Insomnia Severity Index at baseline, at four and eight weeks of treatment. Pre- and post-treatment blood tests for biomarkers were conducted. After intervention, gut microbiota composition was quantified by pyrosequencing the bacterial 16S rRNA gene. The NVP-1704 group had a more significant reduction in depressive symptoms at four and eight weeks of treatment, and anxiety symptoms at four weeks compared to the placebo group. Those receiving NVP-1704 also experienced an improvement in sleep quality. NVP-1704 treatment led to a decrease in serum interleukin-6 levels. Furthermore, NVP-1704 increased Bifidobacteriaceae and Lactobacillacea, whereas it decreased Enterobacteriaceae in the gut microbiota composition. Our findings suggest that probiotic NVP-1704 could be beneficial for mental health and sleep.
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Gluten and FODMAPs Relationship with Mental Disorders: Systematic Review.
Aranburu, E, Matias, S, Simón, E, Larretxi, I, Martínez, O, Bustamante, MÁ, Fernández-Gil, MDP, Miranda, J
Nutrients. 2021;13(6)
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There is growing evidence that gluten and FODMAPs, such as fermentable oligosaccharides, disaccharides, monosaccharides and polyols, can cause gastrointestinal symptoms, inflammation, and immune responses in patients with celiac disease and irritable bowel syndrome. In addition, a high intake of gluten and FODMAPs may also be associated with neurological and psychiatric disorders. Thirteen studies were included in this systematic review to examine the relationship between gluten and FODMAP consumption and illnesses affecting the central nervous system. In addition, the studies examined the effects of potential dietary strategies that consider gluten and FODMAP intake on mental disorders, anxiety, depression, schizophrenia, Alzheimer’s disease, and autism spectrum disorders. Several possible mechanisms identified in this systematic review could contribute to neurological and psychiatric disorders, including the release of proinflammatory cytokines, immune responses, gut dysbiosis, intestinal permeability, and interactions between the gut-brain axis. In patients with fibromyalgia, celiac disease, and irritable bowel syndrome, avoiding or limiting gluten may reduce depression, anxiety, and cognitive impairment. However, the effects of a low-FODMAP diet on the central nervous system are inconclusive. There is some evidence that gluten-free diets can improve cognition in schizophrenia patients. In addition, those with autism spectrum disorders may benefit from a gluten-free diet and a low-FODMAP diet. Further robust research is required to evaluate the beneficial effects of interventions that avoid or restrict the consumption of foods high in FODMAPs and gluten. However, healthcare professionals can use the results of this systematic review to understand the potential benefits of therapeutic interventions that consider the intake of FODMAPs and gluten on illnesses affecting the central nervous system and their possible mechanisms of action.
Abstract
Nowadays, gluten and FODMAP food components (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) are increasingly studied due to their possible relation with extraintestinal-associated conditions. In recent years, gluten-free diets (GFD) and low-FODMAP diets (LFD) are becoming more popular not only in order to avoid the food components that cause intolerances or allergies in some people, but also due to the direct influence of marketing movements or diet trends on feeding habits. Likewise, neurological and psychiatric diseases are currently of increasing importance in developed countries. For this reason, a bibliographic systematic review has been carried out to analyse whether there is a pathophysiological relationship between the dietary intake of gluten or FODMAPs with mental disorders. This review collects 13 clinical and randomized controlled trials, based on the PRISMA statement, which have been published in the last ten years. Based on these results, limiting or ruling out gluten or FODMAPs in the diet might be beneficial for symptoms such as depression, anxiety (7 out of 7 articles found any positive effect), or cognition deficiency (improvements in several cognition test measurements in one trial), and to a lesser extent for schizophrenia and the autism spectrum. Nevertheless, further studies are needed to obtain completely reliable conclusions.
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Regulation of Neurotransmitters by the Gut Microbiota and Effects on Cognition in Neurological Disorders.
Chen, Y, Xu, J, Chen, Y
Nutrients. 2021;13(6)
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Imbalances in the gut microbiota occur in various neurological disorders including Alzheimer’s disease (AD), Parkinson’s disease (PD), autism spectrum disorder and depression. Imbalances in key neurotransmitters are associated with the same disorders. This review focuses on the regulatory mechanisms of the intestinal microbiome and its metabolites on cognitive functions and the pathogeneses of these neurodegenerative diseases. The gut microbiota produce neurotransmitters such as glutamate, GABA, serotonin and dopamine or their precursors. These neurotransmitters are not able to cross the blood brain barrier but the precursors are, therefore the gut microbiota is indirectly involved in the regulation of the production of these key neurotransmitters and therefore neuronal activity and cognitive functions of the brain. The findings demonstrate an association between a healthy gut microbiome structure and balanced neurotransmitter levels in the host. Microbial therapy holds huge promise for the treatment of brain disorders. The development of drugs for neurological disorders must also consider effects on the physiology of the gut microbiome.
Abstract
Emerging evidence indicates that gut microbiota is important in the regulation of brain activity and cognitive functions. Microbes mediate communication among the metabolic, peripheral immune, and central nervous systems via the microbiota-gut-brain axis. However, it is not well understood how the gut microbiome and neurons in the brain mutually interact or how these interactions affect normal brain functioning and cognition. We summarize the mechanisms whereby the gut microbiota regulate the production, transportation, and functioning of neurotransmitters. We also discuss how microbiome dysbiosis affects cognitive function, especially in neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease.
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Efficacy of Zemedy, a Mobile Digital Therapeutic for the Self-management of Irritable Bowel Syndrome: Crossover Randomized Controlled Trial.
Hunt, M, Miguez, S, Dukas, B, Onwude, O, White, S
JMIR mHealth and uHealth. 2021;9(5):e26152
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Cognitive behavioural therapy (CBT) is a proven treatment method to tackle many psychiatric issues. Irritable bowel syndrome (IBS) is considered a chronic gastrointestinal disorder with psychiatric comorbidity. However, patients find it difficult to access CBT for IBS management. As per previous research findings, web-based and telephone-based CBT, self-help CBT books and CBT treatment manuals offer promising therapeutic effects in improving IBS. Therefore, this crossover randomised controlled trial aimed to look at the efficacy of Zemedy, a mobile digital therapeutic application that provides a comprehensive CBT programme to IBS patients. This study found that Zemedy is an effective modality that increases access to effective CBT treatment for IBS patients. Results showed significant improvement in gastrointestinal symptoms, irritable bowel syndrome quality of life, gastrointestinal cognition, visceral sensitivity, fear of food, depression, and improved health-related quality of life in 62 IBS patients enrolled in the immediate treatment group. Further robust studies are required to determine the efficacy of digital applications in IBS patients with significantly higher psychiatric comorbidity. Healthcare practitioners can use the results of the study to understand the importance of digital applications and make them part of intervention strategies.
Abstract
BACKGROUND Patients with irritable bowel syndrome (IBS) experience abdominal pain, altered bowel habits, and defecation-related anxiety, which can result in reduced productivity and impaired health-related quality of life (HRQL). Cognitive behavioral therapy (CBT) has been shown to reduce symptoms of IBS and to improve HRQL, but access to qualified therapists is limited. Smartphone-based digital therapeutic interventions have potential to increase access to guided CBT at scale, but require careful study to assess their benefits and risks. OBJECTIVE The aim of this study was to test the efficacy of a novel app, Zemedy, as a mobile digital therapeutic that delivers a comprehensive CBT program to individuals with IBS. METHODS This was a crossover randomized controlled trial. Participants were recruited online and randomly allocated to either immediate treatment (n=62) or waitlist control (n=59) groups. The Zemedy app consists of 8 modules focusing on psychoeducation, relaxation training, exercise, the cognitive model of stress management, applying CBT to IBS symptoms, reducing avoidance through exposure therapy, behavioral experiments, and information about diet. Users interact with a chatbot that presents the information and encourages specific plans, homework, and exercises. The treatment was fully automated, with no therapist involvement or communication. At baseline and after 8 weeks, participants were asked to complete the battery of primary (Irritable Bowel Syndrome Quality of Life [IBS-QOL], Gastrointestinal Symptom Rating Scale [GSRS]) and secondary (Fear of Food Questionnaire [FFQ], Visceral Sensitivity Index [VSI], Gastrointestinal Cognition Questionnaire [GI-COG], Depression Anxiety Stress Scale [DASS], and Patient Health Questionnaire-9 [PHQ-9]) outcome measures. Waitlist controls were then offered the opportunity to crossover to treatment. All participants were assessed once more at 3 months posttreatment. RESULTS Both intention-to-treat and completer analyses at posttreatment revealed significant improvement for the immediate treatment group compared to the waitlist control group on both primary and secondary outcome measures. Gains were generally maintained at 3 months posttreatment. Scores on the GSRS, IBS-QoL, GI-COG, VSI, and FFQ all improved significantly more in the treatment group (F1,79=20.49, P<.001, Cohen d=1.01; F1,79=20.12, P<.001, d=1.25; F1,79=34.71, P<.001, d=1.47; F1,79=18.7, P<.001, d=1.07; and F1,79=12.13, P=.001, d=0.62, respectively). Depression improved significantly as measured by the PHQ-9 (F1,79=10.5, P=.002, d=1.07), and the DASS Depression (F1,79=6.03, P=.02, d=.83) and Stress (F1,79=4.47, P=.04, d=0.65) subscales in the completer analysis but not in the intention-to-treat analysis. The impact of treatment on HRQL was mediated by reductions in catastrophizing and visceral sensitivity. CONCLUSIONS Despite its relatively benign physical profile, IBS can be an extraordinarily debilitating condition. Zemedy is an effective modality to deliver CBT for individuals with IBS, and could increase accessibility of this evidence-based treatment. TRIAL REGISTRATION ClinicalTrials.gov NCT04170686; https://www.clinicaltrials.gov/ct2/show/NCT04170686.