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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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Wild blueberry (poly)phenols can improve vascular function and cognitive performance in healthy older individuals: a double-blind randomized controlled trial.
Wood, E, Hein, S, Mesnage, R, Fernandes, F, Abhayaratne, N, Xu, Y, Zhang, Z, Bell, L, Williams, C, Rodriguez-Mateos, A
The American journal of clinical nutrition. 2023;117(6):1306-1319
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The risk of developing both cardiovascular and neurodegenerative diseases increases with aging. Growing evidence from epidemiological and human intervention trials indicates that (poly)phenols may have cardioprotective properties as well as the ability to improve cognitive function. The aim of this study was to investigate the effects of daily wild blueberry (WBB) (poly)phenol consumption on vascular function and cognitive performance in healthy older individuals. This study was a randomised, double-blinded, placebo-controlled parallel design study. A total of 61 healthy older individuals were recruited and randomly assigned to one of the two arms; placebo intervention or blueberry intervention group. Results showed that long-term consumption of a dietary achievable amount of WBB enhanced vascular and cognitive function in older adults. Authors conclude that gut microbiota and vascular blood flow may play important roles in mediating the cognitive benefits shown by the consumption of (poly)phenol-rich foods.
Abstract
BACKGROUND Evidence suggests that the intake of blueberry (poly)phenols is associated with improvements in vascular function and cognitive performance. Whether these cognitive effects are linked to increases in cerebral and vascular blood flow or changes in the gut microbiota is currently unknown. METHODS A double-blind, parallel randomized controlled trial was conducted in 61 healthy older individuals aged 65-80 y. Participants received either 26 g of freeze-dried wild blueberry (WBB) powder (302 mg anthocyanins) or a matched placebo (0 mg anthocyanins). Endothelial function measured by flow-mediated dilation (FMD), cognitive function, arterial stiffness, blood pressure (BP), cerebral blood flow (CBF), gut microbiome, and blood parameters were measured at baseline and 12 wk following daily consumption. Plasma and urinary (poly)phenol metabolites were analyzed using microelution solid-phase extraction coupled with liquid chromatography-mass spectrometry. RESULTS A significant increase in FMD and reduction in 24 h ambulatory systolic BP were found in the WBB group compared with the placebo group (0.86%; 95% CI: 0.56, 1.17, P < 0.001; -3.59 mmHg; 95% CI: -6.95, -0.23, P = 0.037; respectively). Enhanced immediate recall on the auditory verbal learning task, alongside better accuracy on a task-switch task was also found following WBB treatment compared with placebo (P < 0.05). Total 24 h urinary (poly)phenol excretion increased significantly in the WBB group compared with placebo. No changes in the CBF or gut microbiota composition were found. CONCLUSIONS Daily intake of WBB powder, equivalent to 178 g fresh weight, improves vascular and cognitive function and decreases 24 h ambulatory systolic BP in healthy older individuals. This suggests that WBB (poly)phenols may reduce future CVD risk in an older population and may improve episodic memory processes and executive functioning in older adults at risk for cognitive decline. Clinical Trial Registration number in clinicaltrials.gov: NCT04084457.
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Psychobiotic Lactobacillus plantarum JYLP-326 relieves anxiety, depression, and insomnia symptoms in test anxious college via modulating the gut microbiota and its metabolism.
Zhu, R, Fang, Y, Li, H, Liu, Y, Wei, J, Zhang, S, Wang, L, Fan, R, Wang, L, Li, S, et al
Frontiers in immunology. 2023;14:1158137
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Test anxiety, characterised by feelings of failure, tension, and worrying when an individual faces a vital test for promoting, occurs prevalently among college students. Lactobacillus plantarum, has become increasingly popular in reducing the severity of anxiety and depression in stressed animal models. The main aim of this study was to evaluate the psychological effects of Lactobacillus plantarum JYLP-326 (JYLP-326) on exam stress-induced behaviours like anxiety, depression, and insomnia. This study enrolled 60 anxious and 30 un-anxious undergraduates preparing for the approaching exams. Out of the 60 anxious participants, 30 were selected randomly to receive the probiotic product and the other 30 received a placebo product. The 30 un-anxious students were assigned as the healthy control group. Results demonstrated that the intervention of JYLP-326 is effective in alleviating exam stress-induced symptoms in college students. Furthermore, it also protected against exam stress-induced dysbiosis of the gut microbiota and the disturbances of faecal metabolomic. Authors conclude that the changed gut microbiota genera and faecal metabolites were closely associated with stress-related symptoms like anxiety/depression and insomnia, indicating that they might be regarded as biomarkers for diagnosing and treating stress and anxiety disorders.
Abstract
INTRODUCTION Test anxiety is a common issue among college students, which can affect their physical and psychological health. However, effective interventions or therapeutic strategies are still lacking. This study aims to evaluate the potential effects of Lactobacillus plantarum JYLP-326 on test anxious college students. METHODS Sixty anxious students were enrolled and randomly allocated to the placebo group and the probiotic group. Both groups were instructed to take placebo and JYLP-326 products twice per day for three weeks, respectively. Thirty unanxious students with no treatments were assigned to a regular control group. The anxiety, depression, and insomnia questionnaires were used to measure students' mental states at the baseline and the end of this study. 16S rRNA sequencing and untargeted metabolomics were performed to analyze the changes in the gut microbiota and fecal metabolism. RESULTS The questionnaire results suggested that JYLP-326 administration could relieve the symptoms of anxiety, depression, and insomnia in test anxious students. The gut microbiomes of the placebo group showed a significantly greater diversity index than the control group (p < 0.05). An increased abundance of Bacteroides and Roseburia at the genus level was observed in the placebo group, and the relative abundance of Prevotella and Bifidobacterium decreased. Whereas, JYLP-326 administration could partly restore the disturbed gut microbiota. Additionally, test anxiety was correlated with disordered fecal metabolomics such as a higher Ethyl sulfate and a lower Cyclohexylamine, which could be reversed after taking JYLP-326. Furthermore, the changed microbiota and fecal metabolites were significantly associated with anxiety-related symptoms. CONCLUSION The results indicate that the intervention of L. plantarum JYLP-326 could be an effective strategy to alleviate anxiety, depression, and insomnia in test anxious college students. The potential mechanism underlying this effect could be related to the regulation of gut microbiota and fecal metabolites.
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HOMEFOOD randomised trial - Six-month nutrition therapy improves quality of life, self-rated health, cognitive function, and depression in older adults after hospital discharge.
Blondal, BS, Geirsdottir, OG, Halldorsson, TI, Beck, AM, Jonsson, PV, Ramel, A
Clinical nutrition ESPEN. 2022;48:74-81
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It is well known that older people are at a higher risk for nutritional inadequacy which is accompanied by depression, impaired cognitive function, and poor overall health. In this secondary analysis of a randomised controlled assessor-blinded dietary intervention trial, the authors examined the effects of six months of nutritional therapy on quality of life, self-rated health, cognitive function, and depression in elderly patients aged 65 years and over. The participants in the intervention group received nutritional therapy (HOMEFOOD) education to overcome malnutrition, which included dietary recommendations to ensure an adequate nutritional intake of energy and protein through diet and additional supplemental protein and energy-rich foods. After six months of nutritional therapy, the intervention group showed improvement in cognitive function, self-rated health, depression score, and quality of life scores, as well as improvements in measures related to weight gain. Further studies need to be conducted in order to determine if nutritional therapy provides additional benefits to older people. However, healthcare professionals can use the results of this study to better understand how nutritional therapy can improve the quality of life and health of older people in comparison to standard care, so they can better advise their patients.
Abstract
BACKGROUND AND AIMS Malnutrition is common among older adults and is related to quality of life, cognitive function, and depression. To what extent nutrition interventions can improve these outcomes remains unclear. The aim of this study was to investigate the effect of nutrition therapy on health-related quality of life (EQ-5D), self-rated health, cognitive function, and depression in community dwelling older adults recently discharged from hospital. METHODS Participants (>65 years) were randomised into an intervention (n = 53) and a control group (n = 53). The intervention group received individualised nutrition therapy based on the nutrition care process including 5 home visits and 3 phone calls, in combination with freely delivered energy- and protein-rich foods and oral nutrition supplements for six months after hospital discharge. EQ-5D, self-rated health, Mini-Mental-State-Examination (MMSE), and the Centre for Epidemiologic Studies Depression - IOWA (CES-D) scale were measured at baseline and at endpoint. RESULTS Two subjects dropped out, one from each arm. The control group experienced an increase in depressive symptoms and a decrease in self-rated health during the study period, while the intervention group experienced increases in cognitive function, self-rated health, and EQ-5D resulting in significant endpoint differences between the groups: EQ-5D (0.102, P = 0.001); self-rated health: 15.876 (P < 0.001); MMSE 1.701 (P < 0.001); depressive symptoms: - 3.072 (P < 0.001); all in favour of the intervention group. Improvements during the intervention in MMSE, self-rated health, and CES-D were significantly related to body weight gain in a linear way. CONCLUSION Cognitive function and mental well-being worsen or stagnate in older adults who receive standard care after hospital discharge. However, a six-month nutrition therapy improves these outcomes leading to statistically and clinically significant endpoint differences between the groups. As improvements were related to body weight gain after hospital discharge, we conclude that the increase in dietary intake, with focus on energy and protein density, and changes in body weight might have contributed to better cognitive function and mental well-being in older adults after the intervention.
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Impulsiveness in children with attention-deficit/hyperactivity disorder after an 8-week intervention with the Mediterranean diet and/or omega-3 fatty acids: a randomised clinical trial.
San Mauro Martin, I, Sanz Rojo, S, González Cosano, L, Conty de la Campa, R, Garicano Vilar, E, Blumenfeld Olivares, JA
Neurologia. 2022;37(7):513-523
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From a clinical perspective, impulsiveness is an important diagnostic characteristic of several psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD). ADHD is a neurodevelopmental disorder characterised by a persistent pattern of lack of attention and/or hyperactivity and impulsiveness. Dietary approaches to the treatment of ADHD include fatty acid supplementation, particularly with omega-3 polyunsaturated fatty acids (n-3 PUFA) The aim of this study was to analyse changes in the Barratt Impulsiveness Scale (BIS-11c) scores in children with ADHD after an 8-week intervention with the Mediterranean diet, omega-3 fatty acid supplementation, or Mediterranean diet plus omega-3 fatty acid supplementation, as compared to a control group. This study is a cross-sectional, observational cohort study of an 8-week dietary intervention in children with ADHD. Participants (n= 60) were divided into 4 groups, with a control group and 3 intervention groups. Results show that participants with ADHD taking n-3 PUFA supplements (550 mg EPA and 225 mg DHA daily) showed significantly lower levels of impulsiveness than those adopting a Mediterranean diet and controls. These participants also scored lower on all subscales of the BIS (cognitive, motor, and lack of planning). However, there weren’t any differences in impulsive behaviour between patients taking n-3 PUFA supplements and those taking supplements and adhering to the Mediterranean diet. Authors conclude that omega-3 rich (EPA/DHA) supplements should be considered for paediatric patients with ADHD, particularly those with the predominantly hyperactive-impulsive subtype.
Expert Review
Conflicts of interest:
None
Take Home Message:
- The results from this study show no statistically significant differences between groups, except for the group of children receiving omega-3 supplementation.
- Patients with ADHD receiving omega 3 fatty acids (550 mg eicosatetraenoic acid [EPA] and 225 mg docosahexaenoic acid [DHA]) daily presented with less impulsive behaviour than controls with ADHD and patients who adopted a Mediterranean diet.
- EPA/DHA supplements may be considered for paediatric patients with ADHD, particularly those with the predominantly hyperactive-impulsive subtype.
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, cross-sectional study was conducted to investigate the effects of a Mediterranean diet and Omega-3 supplementation on the impulsiveness in children with attention-deficit/hyperactivity disorder (ADHD).
Methods
76 Children ages 6-16 years of either sex, with a diagnosis of ADHD, were divided into 4 groups, with a control group and 3 intervention groups. Group 1 (controls) followed their usual diet. Group 2 (Mediterranean diet) adopted a Mediterranean diet according to a series of recommendations. Group 3 (omega-3) received omega-3 fatty acid supplements. Group 4 (Mediterranean diet + omega-3) adopted the same diet as group 2 and also received omega 3 fatty acid supplements.
Dieticians provided a tailored Mediterranean diet for each participant. The Omega-3 supplement comprised of 550mg EPA and 225mg of DHA sourced from deep-sea sardines and anchovies.
The Barratt Impulsiveness Scale (BIS-11c) was administered to every child individually to evaluate impulsiveness. The KIDMED questionnaire was administered to evaluate the participant’s adherence to the Mediterranean diet. The study was conducted over 8 weeks. At the endpoint, 60/76 subjects completed the study.
Results
Primary clinical outcomes were:
- Children in the omega-3 supplement group showed a significant drop in the Barratt Impulsiveness Scale score after the intervention (from 49 to 45.10; p =.049).
- Children in the Mediterranean diet and supplement group showed higher cognitive scores (from 2.758 to 2.631).
Limitation
There was a statistically significant difference between groups for the KIDMED score (a measure of adherence to a Mediterranean diet), reflecting a higher adherence to the Mediterranean diet by the control group.
Clinical practice applications:
- Approximately 20%-40% of patients with ADHD do not respond to pharmacological treatment therefore there is a need for alternative options.
- Based on these findings, a practitioner could therefore consider recommending 550mg of eicosatetraenoic acid (EPA) and 225mg of docosahexaenoic acid (DHA) sourced from deep-sea sardines and anchovies for at least 8 weeks to help reduce impulsiveness and improve cognitive function in patients with a hyperactive-impulsive subtype of ADHD.
Considerations for future research:
- This study included combined types of ADHD therefore further investigations are needed on each type of ADHD using different interventions to establish which intervention works best.
- Assessment of diet and omega status before intervention was not conducted, which may have affected outcomes in this study. Further research could consider gathering this data at baseline.
- Larger studies are also needed to determine the relationship between BIS scores and treatments to deepen our understanding of this topic.
- Conflict of interest statement: This study was fully funded by the manufacturer of the provided Omega 3 supplement.
Abstract
INTRODUCTION The Barratt Impulsiveness Scale (BIS) is a self-administered instrument designed to assess the personality/behavioural construct of impulsiveness. Impulsiveness has been associated with several psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD). This study assesses the progression of impulsive behaviour in children with ADHD after an 8-week dietary intervention with the Mediterranean diet and/or omega-3 fatty acid supplementation, by using a version of the 11-item BIS adapted for children (BIS-11c). METHODS This cross-sectional study includes 60 children with ADHD from the region of Madrid, Spain. Participants were divided into 4 groups, with one control group and 3 intervention groups (Mediterranean diet; omega-3 supplementation; and Mediterranean diet plus omega-3 supplementation). A personalised Mediterranean diet was designed for members of groups 2 and 4. The BIS-11c was administered to determine the level of impulsiveness, and the KIDMED test was used to assess adherence to the Mediterranean diet. RESULTS The supplementation group showed a fairly significant decrease in the total BIS-11c (P = .049). Total cognitive score slightly decreased in the diet and supplementation groups. Only the control group showed a considerable decrease in the total motor score. Total nonplanning scores were lower in all groups after the intervention. Baseline and final BIS-11c scores were positively correlated with treatments (r > 0.9). CONCLUSION An intake of 550 mg EPA fatty acid and 225 mg DHA fatty acid per day for 8 weeks is associated with less marked impulsive behaviour in children with ADHD. A Mediterranean diet may improve BIS scores, although our results are not conclusive in this population.
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Effect of Vitamin D Supplementation on Inflammatory Biomarkers in School-Aged Children with Attention Deficit Hyperactivity Disorder.
Samadi, M, Gholami, F, Seyedi, M, Jalali, M, Effatpanah, M, Yekaninejad, MS, Abdolahi, M, Chamari, M, Mohammadzadeh Honarvar, N
International journal of clinical practice. 2022;2022:1256408
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Attention deficit hyperactivity disorder (ADHD) is one of the most prevalent psychiatric and developmental disorders among children and adolescents. Besides clinical impairments, these children have challenges with school performance and independent socioeconomic factors. The aim of this study was to assess the possible effects of vitamin D on inflammatory cytokines (tumour necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6)) levels in children with ADHD. This study is a randomised, double-blind, placebo-controlled clinical trial which was conducted on 86 children aged 6–12. Patients were randomly assigned to two groups to receive vitamin D3 or a placebo. Results show children with ADHD taking vitamin D supplementation for 3 months demonstrated a significant increase in serum levels of Vitamin D3. However, serum levels of IL-6 and TNF-α were not significantly influenced by vitamin D administration. Authors conclude that their findings failed to find a favourable effect of 3 months of supplementation with vitamin D on inflammatory cytokines. Thus, they highly recommend conducting further studies with different doses of vitamin D and various designs in addition to differences in the characteristics of participants.
Abstract
METHOD This randomized double-blind, placebo-controlled trial was conducted on 75 school-aged children with a diagnosis of ADHD based on DSM-V criteria. Children were randomly allocated to receive either vitamin D3 (2000 IU/day) or a placebo for 3 months. Serum IL-6, TNF-α, and 25(OH) D were assessed before and after the intervention to determine the effects of vitamin D on the highlighted parameters. RESULTS Serum levels of 25(OH) D increased significantly in the vitamin D group (P=0.01). However, no significant differences in serum IL-6 and TNF-α were found between both groups at the baseline and at the end of the intervention. CONCLUSION The findings revealed that vitamin D supplementation for 3 months is not efficacious in reducing inflammatory cytokines in children with ADHD. Further studies are required to confirm these results.
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Changes in Eating Behaviors Following Taste Education Intervention: Focusing on Children with and without Neurodevelopmental Disorders and Their Families: A Randomized Controlled Trial.
Thorsteinsdottir, S, Njardvik, U, Bjarnason, R, Olafsdottir, AS
Nutrients. 2022;14(19)
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Children with atypical brain development such as attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) can frequently exhibit fussiness to eat new and healthy foods. Well-meaning parents can often try and encourage their children to eat new and healthy foods through methods such as rewarding, a practice which can result in unfavourable effects on learning, behaviour, and physical health. This randomised control trial of 95 parent-child family units aimed to determine whether parental education as part of a wider taste education programme could improve problematic eating behaviour in children with both typical and atypical brain development. After 7-weeks of taste education, problematic child mealtime behaviours were improved and parental concern about their child’s diet was decreased. It was reported that this benefit was marginally more pronounced in children with atypical brain development, which may have been due to parents of these children more effectively utilising the methods they were taught. It was concluded that regardless of brain development in children, a taste education programme is an effective way to improve mealtime behaviours and reduce parental concern about their child’s diet.
Abstract
Fussy-eating children often display problematic behaviors around mealtimes, such as irritation, opposition, or may even throw tantrums. This may lead to reduced food variety and poor nutritional profiles, which may increase parents' worries about their children's diet, particularly when the children also have neurodevelopmental disorders (ND) such as Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactive Disorder (ADHD). To investigate the effect of Taste Education on problematic mealtime behaviors, 81 children aged 8-12 years, with ND (n = 33) and without (n = 48), and their parents, participated in a 7-week Taste Education intervention. Children were matched on age, sex, and ND, and allocated at random into Immediate-intervention and Delayed-intervention groups. Parents completed the Meals in Our Household Questionnaire (MiOH). To examine changes in MiOH-scores, repeated-measures analysis-of-variance with time-points were used, with condition as factors (Immediate intervention and Delayed intervention). Baseline measures were adjusted for, and a robust linear mixed-model was fitted. Results showed superior outcomes for Intervention compared to waiting on all measures of MiOH, with stable effects through six-month follow-up. Differences were non-significant between children with and without ND. The Taste Education program suggests a promising, simple, and non-intrusive way to reduce children's problematic mealtime behaviors in the long term.
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A combination of green tea, rhodiola, magnesium and B vitamins modulates brain activity and protects against the effects of induced social stress in healthy volunteers.
Boyle, NB, Billington, J, Lawton, C, Quadt, F, Dye, L
Nutritional neuroscience. 2022;25(9):1845-1859
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Stress is a leading cause of work-related time off. Low magnesium intake has been shown to be associated with anxiety and supplementation has been shown to relieve anxiety-related-symptoms, especially when combined with B vitamins. Green tea and rhodiola have also been used to alleviate stress, anxiety, and fatigue, the latter after just 3 days of intake. This randomised control trial of 100 moderately stressed adults aimed to determine the effects of combining magnesium, B vitamins, green tea, and rhodiola after induced social stress. The results showed that supplementation with a combination of magnesium, B vitamins, green tea, and rhodiola induced a relaxed, alert state and lowered stress, anxiety, and mood disturbances. However, it did not affect stress hormones, heart rate or blood pressure in response to stress. It was concluded that combination treatment is a promising therapy for stress. This study could be used by healthcare professionals to recommend the combination of magnesium, B vitamins, green tea, and rhodiola to individuals with social anxiety before they enter a socially stressful situation.
Abstract
BACKGROUND Magnesium (Mg), green tea and rhodiola extracts have, in isolation, been shown to possess stress and anxiety relieving effects. Green tea and rhodiola have been shown to modulate EEG oscillatory brain activity associated with relaxation and stress perception. The combined capacity of these ingredients to confer protective effects under conditions of acute stress has yet to be examined. We tested the hypothesis that a combination of Mg (with B vitamins) + green tea + rhodiola would acutely moderate the effects of stress exposure. METHODS A double blind, randomised, placebo controlled, parallel group design was employed (Clinicaltrials.gov:NCT03262376; 25/0817). One hundred moderately stressed adults received oral supplementation of either (i) Mg + B vitamins + green tea + rhodiola; (ii) Mg + B vitamins + rhodiola; (iii) Mg + B vitamins + green tea; or (iv) placebo. After supplementation participants were exposed to the Trier Social Stress Test. The effects of the study treatments on electroencephalogram (EEG) resting state alpha and theta, subjective state/mood, blood pressure, heart rate variability and salivary cortisol responses after acute stress exposure were assessed. RESULTS The combined treatment significantly increased EEG resting state theta (p < .02) - considered indicative of a relaxed, alert state, attenuated subjective stress, anxiety and mood disturbance, and heightened subjective and autonomic arousal (p < .05). CONCLUSIONS Mg, B vitamins, rhodiola and green tea extracts are a promising combination of ingredients that may enhance coping capacity and offer protection from the negative effects of stress exposure.Trial registration: ClinicalTrials.gov identifier: NCT03262376.
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Probiotic Mixture Containing Lactobacillus helveticus, Bifidobacterium longum and Lactiplantibacillus plantarum Affects Brain Responses to an Arithmetic Stress Task in Healthy Subjects: A Randomised Clinical Trial and Proof-of-Concept Study.
Edebol Carlman, HMT, Rode, J, König, J, Repsilber, D, Hutchinson, AN, Thunberg, P, Persson, J, Kiselev, A, Pruessner, JC, Brummer, RJ
Nutrients. 2022;14(7)
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Physiological and psychological stress can affect gut function and its interaction with the brain (gut-brain axis). Different types of stress and different phases of stress regulation can affect the brain in different ways. Manipulation of the gut microbiota using probiotic bacteria has been shown to improve cognition and stress response. However, probiotic interventions are likely to have different effects depending on the strains used. The aim of this study was to assess the effects of a probiotic intervention on brain activity and stress response. This study is a randomised double-blinded placebo-controlled crossover study with 22 healthy subjects. Subjects were randomised to two study groups receiving the intervention in different orders (probiotics or placebo first). Results demonstrate that the probiotic intervention: - altered activity in specific brain regions known to regulate emotion and stress response. - significantly altered functional connectivity between the upper limbic and medioventral regions. - did not affect the activation of other limbic or subcortical areas. Authors conclude that their findings could further lead to possible clinical implications for improving stress resilience and potential roles in the treatment of affective and gut-brain axis disorders.
Abstract
Probiotics are suggested to impact physiological and psychological stress responses by acting on the gut-brain axis. We investigated if a probiotic product containing Bifidobacterium longum R0175, Lactobacillus helveticus R0052 and Lactiplantibacillus plantarum R1012 affected stress processing in a double-blinded, randomised, placebo-controlled, crossover proof-of-concept study (NCT03615651). Twenty-two healthy subjects (24.2 ± 3.4 years, 6 men/16 women) underwent a probiotic and placebo intervention for 4 weeks each, separated by a 4-week washout period. Subjects were examined by functional magnetic resonance imaging while performing the Montreal Imaging Stress Task (MIST) as well as an autonomic nervous system function assessment during the Stroop task. Reduced activation in regions of the lateral orbital and ventral cingulate gyri was observed after probiotic intervention compared to placebo. Significantly increased functional connectivity was found between the upper limbic region and medioventral area. Interestingly, probiotic intervention seemed to predominantly affect the initial stress response. Salivary cortisol secretion during the task was not altered. Probiotic intervention did not affect cognitive performance and autonomic nervous system function during Stroop. The probiotic intervention was able to subtly alter brain activity and functional connectivity in regions known to regulate emotion and stress responses. These findings support the potential of probiotics as a non-pharmaceutical treatment modality for stress-related disorders.
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Feed your microbes to deal with stress: a psychobiotic diet impacts microbial stability and perceived stress in a healthy adult population.
Berding, K, Bastiaanssen, TFS, Moloney, GM, Boscaini, S, Strain, CR, Anesi, A, Long-Smith, C, Mattivi, F, Stanton, C, Clarke, G, et al
Molecular psychiatry. 2022
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Psychobiotic describe any exogenous intervention that leads to a bacterially mediated impact on the brain. Probiotics and prebiotics have shown promising results as psychobiotic agents in both animal and human studies. The aim of this study was to investigate the potential of a whole diet psychobiotic approach to modulate the microbiota composition and function, affect responses to and feelings of stress and improve mood in a healthy population. This study is a single-blind, randomized, controlled study which recruited healthy adult (male and female) participants with poor dietary habits, aged 18–59 years. Participants were block randomized (block of 4, stratified by gender) into either intervention or control group using randomly permuted blocks and were instructed to follow their respective diet for 4 weeks. Results show that a short term psychobiotic dietary intervention improved perceived stress in a healthy population, while eliciting specific metabolic changes in the gut microbiota. Authors conclude that underlying microbial influences need to be investigated and future preclinical experiments are required to explore causality and decipher mechanistic pathways.
Expert Review
Conflicts of interest:
None
Take Home Message:
Eating foods known to have a positive influence on gut microbial composition could elicit benefits in terms of reducing perceived stress and improving sleep quality.
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:
This RCT explored the impact of a psychobiotic diet, compared to a control diet, on perceived stress, sleep and gut microbiota.
A high psychobiotic diet is one high in prebiotic and fermented foods. In this study, a psychobiotic diet included daily recommended consumption and servings of the following:
- High prebiotic fruit & veg (6-8)
- Grains (5-8)
- Fermented foods (2-3)
- Legumes (3-4 per week)
Methodology:
- A single-blind, randomised, controlled study
- 45 healthy adults (18-59 years) with poor dietary habits
- Sample size determined by previous microbiome research - target not reached due to introduction of covid restrictrictions
- Active intervention (n=24) received dietitian advice to follow psychobitoic diet
- Control intervention (n=21) received dietitian advice largely based on the Irish Healthy Eating Guidelines food pyramid
- Intervention duration 4 weeks.
- Assessed on questionnaire measures of perceived stress and sleep, pre and post-intervention (no primary outcome defined)
- Shotgun microbiome analysis on stool samples, pre and post-intervention
Results:
- Perceived stress improved in the psychobiotic diet group
- Subjective sleep quality improved in the psychobiotic diet group
- Only subtle changes in microbial composition and function
- More stable microbiota throughout the study (regardless of diet) was correlated with greater changes in perceived stress
- Neither cortisol awakening response nor measured immune markers were affected by dietary intervention
Conclusions:
- Using a diet targeted to positively modulate gut-brain communication may have the potential for reducing stress and improving sleep
- Although improvements in stress were only observed for the intervention group – the post-intervention stress levels were not significantly different between the groups.
- Thus, we should interpret the results with some caution
Clinical practice applications:
- Providing advice on dietary intake of foods known to positively impact gut microbiota may be helpful for individuals affected by stress or sleep problems
- The inclusion of the following foods may be helpful:
- High prebiotic fruit & veg (6-8 per day)
- Grains (5-8 per day)
- Fermented foods (2-3 per day)
- Legumes (3-4 per week)
Considerations for future research:
- Important to replicate these results in a larger sample
- It might be helpful to investigate individual aspects of the diet separately, to assess their individual impact
- Objective measures of sleep (such as actigraphy recordings) might provide additionally useful findings
- It would be interesting to explore the effect of the psychobiotic diet in other conditions
- Chronobiology or chrononutrition - i.e. looking at timing of the foods proposed in the section above
Abstract
The impact of diet on the microbiota composition and the role of diet in supporting optimal mental health have received much attention in the last decade. However, whether whole dietary approaches can exert psychobiotic effects is largely understudied. Thus, we investigated the influence of a psychobiotic diet (high in prebiotic and fermented foods) on the microbial profile and function as well as on mental health outcomes in a healthy human population. Forty-five adults were randomized into either a psychobiotic (n = 24) or control (n = 21) diet for 4 weeks. Fecal microbiota composition and function was characterized using shotgun sequencing. Stress, overall health and diet were assessed using validated questionnaires. Metabolic profiling of plasma, urine and fecal samples was performed. Intervention with a psychobiotic diet resulted in reductions of perceived stress (32% in diet vs. 17% in control group), but not between groups. Similarly, biological marker of stress were not affected. Additionally, higher adherence to the diet resulted in stronger decreases in perceived stress. While the dietary intervention elicited only subtle changes in microbial composition and function, significant changes in the level of 40 specific fecal lipids and urinary tryptophan metabolites were observed. Lastly, microbial volatility was linked to greater changes in perceived stress scores in those on the psychobiotic diet. These results highlight that dietary approaches can be used to reduce perceived stress in a human cohort. Using microbiota-targeted diets to positively modulate gut-brain communication holds possibilities for the reduction of stress and stress-associated disorders, but additional research is warranted to investigate underlying mechanisms, including the role of the microbiota.