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Journal of the International Society of... 2016Fatigue, mood disturbances, under performance and gastrointestinal distress are common among athletes during training and competition. The psychosocial and physical... (Review)
Review
Fatigue, mood disturbances, under performance and gastrointestinal distress are common among athletes during training and competition. The psychosocial and physical demands during intense exercise can initiate a stress response activating the sympathetic-adrenomedullary and hypothalamus-pituitary-adrenal (HPA) axes, resulting in the release of stress and catabolic hormones, inflammatory cytokines and microbial molecules. The gut is home to trillions of microorganisms that have fundamental roles in many aspects of human biology, including metabolism, endocrine, neuronal and immune function. The gut microbiome and its influence on host behavior, intestinal barrier and immune function are believed to be a critical aspect of the brain-gut axis. Recent evidence in murine models shows that there is a high correlation between physical and emotional stress during exercise and changes in gastrointestinal microbiota composition. For instance, induced exercise-stress decreased cecal levels of spp and increased which have well defined roles in intestinal mucus degradation and immune function. Diet is known to dramatically modulate the composition of the gut microbiota. Due to the considerable complexity of stress responses in elite athletes (from leaky gut to increased catabolism and depression), defining standard diet regimes is difficult. However, some preliminary experimental data obtained from studies using probiotics and prebiotics studies show some interesting results, indicating that the microbiota acts like an endocrine organ (e.g. secreting serotonin, dopamine or other neurotransmitters) and may control the HPA axis in athletes. What is troubling is that dietary recommendations for elite athletes are primarily based on a low consumption of plant polysaccharides, which is associated with reduced microbiota diversity and functionality (e.g. less synthesis of byproducts such as short chain fatty acids and neurotransmitters). As more elite athletes suffer from psychological and gastrointestinal conditions that can be linked to the gut, targeting the microbiota therapeutically may need to be incorporated in athletes' diets that take into consideration dietary fiber as well as microbial taxa not currently present in athlete's gut.
Topics: Athletes; Athletic Performance; Brain; Diet; Food; Gastrointestinal Microbiome; Gastrointestinal Tract; Hormones; Humans; Probiotics; Sports Nutritional Physiological Phenomena; Stress, Psychological
PubMed: 27924137
DOI: 10.1186/s12970-016-0155-6 -
Psychoneuroendocrinology Mar 2022The gut microbiota is the set of microorganisms present in the gut, and it is connected to the central nervous system via the gut-brain axis. Despite there is not a... (Review)
Review
The gut microbiota is the set of microorganisms present in the gut, and it is connected to the central nervous system via the gut-brain axis. Despite there is not a definitive description of the eubiotic microbiota architecture, numerous studies have demonstrated its involvement in human behaviour and its relationship with several pathologies. This is a systematic review about the association between dysbiosis on the gut microbiota and the presence of neurological or neuropsychiatric diseases such as cognitive impairment, Alzheimer's disease, Parkinson's disease, ADHD, and depression. Furthermore, this study analyzes the potential benefits of psychobiotics supplementation for these pathologies. Searches were conducted in the electronic databases PubMed and PsycINFO. 17 articles were included in this review, the majority were published after 2019. The results showed that gut dysbiosis predicts the development of these pathologies and influences their pathogenesis. In addition, it was found that different psychobiotics, mainly dietary fibers and probiotics of the Lactobacillus family, improved different cognitive functions such as cognitive performance and induce a reduced cortisol response. Improvement in different cognitive functions is possible when understanding gut microbiota-brain axis, enteric nervous system, neural-immune system, neuroendocrine system, and central nervous system's relationship.
Topics: Brain; Dysbiosis; Gastrointestinal Microbiome; Humans; Microbiota; Probiotics
PubMed: 34942539
DOI: 10.1016/j.psyneuen.2021.105640 -
Journal of Cachexia, Sarcopenia and... Dec 2021Gut microbiota dysbiosis and sarcopenia commonly occur in the elderly. Although the concept of the gut-muscle axis has been raised, the casual relationship is still... (Review)
Review
BACKGROUND
Gut microbiota dysbiosis and sarcopenia commonly occur in the elderly. Although the concept of the gut-muscle axis has been raised, the casual relationship is still unclear. This systematic review analyses the current evidence of gut microbiota effects on muscle/sarcopenia.
METHODS
A systematic review was performed in PubMed, Embase, Web of Science, and The Cochrane Library databases using the keywords (microbiota* OR microbiome*) AND (sarcopen* OR muscle). Studies reporting the alterations of gut microbiota and muscle/physical performance were analysed.
RESULTS
A total of 26 pre-clinical and 10 clinical studies were included. For animal studies, three revealed age-related changes and relationships between gut microbiota and muscle. Three studies focused on muscle characteristics of germ-free mice. Seventy-five per cent of eight faecal microbiota transplantation studies showed that the recipient mice successfully replicated the muscle phenotype of donors. There were positive effects on muscle from seven probiotics, two prebiotics, and short-chain fatty acids (SCFAs). Ten studies investigated on other dietary supplements, antibiotics, exercise, and food withdrawal that affected both muscle and gut microbiota. Twelve studies explored the potential mechanisms of the gut-muscle axis. For clinical studies, 6 studies recruited 676 elderly people (72.8 ± 5.6 years, 57.8% female), while 4 studies focused on 244 young adults (29.7 ± 7.8 years, 55.4% female). The associations of gut microbiota and muscle had been shown in four observational studies. Probiotics, prebiotics, synbiotics, fermented milk, caloric restriction, and exercise in six studies displayed inconsistent effects on muscle mass, function, and gut microbiota.
CONCLUSIONS
Altering the gut microbiota through bacteria depletion, faecal transplantation, and various supplements was shown to directly affect muscle phenotypes. Probiotics, prebiotics, SCFAs, and bacterial products are potential novel therapies to enhance muscle mass and physical performance. Lactobacillus and Bifidobacterium strains restored age-related muscle loss. Potential mechanisms of microbiome modulating muscle mainly include protein, energy, lipid, and glucose metabolism, inflammation level, neuromuscular junction, and mitochondrial function. The role of the gut microbiota in the development of muscle loss during aging is a crucial area that requires further studies for translation to patients.
Topics: Aged; Animals; Fecal Microbiota Transplantation; Female; Gastrointestinal Microbiome; Humans; Male; Mice; Prebiotics; Sarcopenia; Synbiotics
PubMed: 34523250
DOI: 10.1002/jcsm.12784 -
Psychoneuroendocrinology Feb 2022Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the development of major depressive disorder (MDD) in adulthood. Less work has... (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION
Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in the development of major depressive disorder (MDD) in adulthood. Less work has focused on the role of the HPA axis in depression in adolescence and young adulthood globally. The aim of this study was to conduct a systematic review and meta-analysis of worldwide research investigating the relationship between cortisol, a measure of HPA axis activity, and MDD in adolescence and young adulthood.
METHOD
We searched MEDLINE, PsycINFO, Cochrane Database of Systematic Reviews, Web of Science, Lilacs, African Journals Online, and Global Health for studies which examined the relationship between cortisol and MDD in global youth (10-24 years old).
RESULTS
Twenty-six studies were included in the systematic review and 14 were eligible for the meta-analysis, but only one study included young adults in their sample. Results from the meta-analysis demonstrated that elevated morning, but not evening, cortisol levels was prospectively associated with later MDD development in adolescence and young adulthood. However, morning cortisol levels did not significantly differ between healthy controls and individuals with MDD in cross-sectional studies. Afternoon cortisol and cortisol stress response also did not differ between adolescents with MDD and healthy controls. Qualitative synthesis of the three studies examining nocturnal cortisol showed higher nocturnal cortisol was both longitudinally and cross-sectionally associated with MDD in adolescence.
CONCLUSION
Our findings suggest elevated morning cortisol precedes depression in adolescence. Despite this, we did not find any differences in other cortisol measures in association with MDD in cross-sectional studies. Taken together, these findings suggest that elevated morning and nocturnal cortisol are risk factors for depression in adolescence rather than a biomarker of existing MDD. This supports a role for the hyperactivity of the HPA axis in the development of MDD in adolescence. Most of the studies were from high-income-countries (HICs) and thus further work would need to be conducted in low- and middle-income countries (LMICs) to understand if our findings are generalisable also to these populations.
Topics: Adolescent; Adult; Child; Cross-Sectional Studies; Depression; Depressive Disorder, Major; Humans; Hydrocortisone; Hypothalamo-Hypophyseal System; Pituitary-Adrenal System; Young Adult
PubMed: 34920399
DOI: 10.1016/j.psyneuen.2021.105625 -
Gut Sep 2022The role of the brain-gut axis is of increasing interest in IBD, as the link between common mental disorders and GI inflammation may be bidirectional. We performed a... (Meta-Analysis)
Meta-Analysis
OBJECTIVE
The role of the brain-gut axis is of increasing interest in IBD, as the link between common mental disorders and GI inflammation may be bidirectional. We performed a systematic review examining these issues.
DESIGN
We searched EMBASE Classic and EMBASE, Medline, and APA PsychInfo (to 11 July 2021) for longitudinal follow-up studies examining effect of symptoms of anxiety or depression on subsequent adverse outcomes in IBD, or effect of active IBD on subsequent development of symptoms of anxiety or depression. We pooled relative risks (RRs) and HRs with 95% CIs for adverse outcomes (flare, escalation of therapy, hospitalisation, emergency department attendance, surgery or a composite of any of these) according to presence of symptoms of anxiety or depression at baseline, or RRs and HRs with 95% CIs for new onset of symptoms of anxiety or depression according to presence of active IBD at baseline.
RESULTS
We included 12 separate studies, recruiting 9192 patients. All 12 studies examined brain-to-gut effects. Anxiety at baseline was associated with significantly higher risks of escalation of therapy (RR=1.68; 95% CI 1.18 to 2.40), hospitalisation (RR=1.72; 95% CI 1.01 to 2.95), emergency department attendance (RR=1.30; 95% CI 1.21 to 1.39), or a composite of any adverse outcome. Depression at baseline was associated with higher risks of flare (RR=1.60; 95% CI 1.21 to 2.12), escalation of therapy (RR=1.41; 95% CI 1.08 to 1.84), hospitalisation (RR=1.35; 95% CI 1.17 to 1.57), emergency department attendance (RR=1.38; 95% CI 1.22 to 1.56), surgery (RR=1.63; 95% CI 1.19 to 2.22) or a composite of any of these. Three studies examined gut-to-brain effects. Active disease at baseline was associated with future development of anxiety or depression (RR=2.24; 95% CI 1.25 to 4.01 and RR=1.49; 95% CI 1.11 to 1.98, respectively).
CONCLUSION
Bidirectional effects of the brain-gut axis are present in IBD and may influence both the natural history of the disease and psychological health.
Topics: Anxiety; Brain-Gut Axis; Follow-Up Studies; Humans; Inflammatory Bowel Diseases; Prognosis
PubMed: 34725197
DOI: 10.1136/gutjnl-2021-325985 -
International Journal of Health Sciences 2021The basic objective of this systematic review was to identify potential biomarkers for chronic stress. (Review)
Review
OBJECTIVE
The basic objective of this systematic review was to identify potential biomarkers for chronic stress.
METHODS
A systematic review of studies linking biomarkers in people with chronic stress was conducted using PRISMA guidelines. The last 40 years' studies were included in the systematic review with no age restrictions; animal studies were excluded from the study. Electronic databases including PubMed, Embase, and Google Scholar were searched for the study purpose. The studies were searched using the combinations of search terms that comprised chronic stress together with the keywords hypothalamic-pituitary-adrenal axis (HPA axis), autonomic nervous system (ANS), immune system, metabolic biomarkers, cortisol, hair cortisol, salivary cortisol, urinary cortisol, epinephrine, norepinephrine, adrenocorticotropic hormone (ACTH), brain-derived neurotropic factor (BDNF), metabolic biomarkers, antioxidants, glucose, hemoglobin, C-reactive protein (CRP), cytokines, pro-inflammatory cytokines, anti-inflammatory cytokines, and tumor necrosis factor (TNF).
RESULTS
A total of 37 studies out of 671 studies met the eligibility criteria and were included in this review. Potential diagnostic biomarkers of chronic stress included cortisol, ACTH, BDNF, catecholamines, glucose, HbA1c, triglycerides, cholesterol, prolactin, oxytocin, dehydroepiandrosterone sulfate (DHEA-S), CRP, and interleukin - 6 and 8. While the others including antioxidants and natural killer (NK) cells require further validation. Taken together, addition, these stress biomarkers have critical prognostic capacities for stress-associated diseases and therapeutic guidance.
CONCLUSION
This systematic review provides an update to the literature by highlighting the role of physiological biomarkers in chronic stress and describing their prognostic and therapeutic values.
PubMed: 34548863
DOI: No ID Found -
Depression and Anxiety Jan 2018Depression has repeatedly been linked to subclinical hypothyroidism, and thyroid hormones have successfully been used to augment antidepressant treatment. By contrast,... (Review)
Review
Depression has repeatedly been linked to subclinical hypothyroidism, and thyroid hormones have successfully been used to augment antidepressant treatment. By contrast, the extent of thyroid dysfunction in anxiety disorders remains less clear. This is surprising, given that anxiety-related symptoms (e.g., nervousness, palpitations, increased perspiration) are highly prevalent in hyperthyroidism. The present study was undertaken to synthesize the literature on hypothalamic-pituitary-thyroid (HPT) axis functioning in anxiety disorders. The PubMed and PsycINFO databases were systematically searched. Three types of studies were included: (1) "comorbidity studies" assessing the prevalence of thyroid disorders in individuals with anxiety disorders, (2) "case-control studies" comparing HPT parameters between patients and controls, and (3) "correlational studies" assessing self-reported anxiety levels and HPT parameters. Risk of bias was assessed via a standardized quality rating. Twenty studies were eligible. Nearly all found the comorbidity between anxiety and thyroid disorders was significant. Half of the studies additionally supported the notion of subtle thyroid dysfunction in that thyroid-stimulating hormone (TSH) responses to the administration of thyrotropin-releasing hormone (TRH) were blunted and an inverse relationship was observed between self-reported anxiety levels and TSH. Overall, HPT assessments were well conducted, but several studies failed to adjust their analyses for smoking, body mass index (BMI), and depression. The findings resonate well with clinical recommendations to routinely screen for thyroid disorders in patients with anxiety disorders, and with what is known from basic research about thyroid-brain interactions. The results of the risk of bias assessment underscore the importance of further high-quality experimental and longitudinal epidemiological research.
Topics: Anxiety Disorders; Humans; Hypothalamo-Hypophyseal System; Pituitary-Adrenal System; Thyroid Diseases
PubMed: 29064607
DOI: 10.1002/da.22692 -
Health Services Research Oct 2019To identify patient-reported experience measures (PREMs), assess their validity and reliability, and assess any bias in the study design of PREM validity and reliability...
OBJECTIVES
To identify patient-reported experience measures (PREMs), assess their validity and reliability, and assess any bias in the study design of PREM validity and reliability testing.
DATA SOURCES/STUDY SETTING
Articles reporting on PREM development and testing sourced from MEDLINE, CINAHL and Scopus databases up to March 13, 2018.
STUDY DESIGN
Systematic review.
DATA COLLECTION/EXTRACTION METHODS
Critical appraisal of PREM study design was undertaken using the Appraisal tool for Cross-Sectional Studies (AXIS). Critical appraisal of PREM validity and reliability was undertaken using a revised version of the COSMIN checklist.
PRINCIPAL FINDINGS
Eighty-eight PREMs were identified, spanning across four main health care contexts. PREM validity and reliability was supported by appropriate study designs. Internal consistency (n = 58, 65.2 percent), structural validity (n = 49, 55.1 percent), and content validity (n = 34, 38.2 percent) were the most frequently reported validity and reliability tests.
CONCLUSIONS
Careful consideration should be given when selecting PREMs, particularly as seven of the 10 validity and reliability criteria were not undertaken in ≥50 percent of the PREMs. Testing PREM responsiveness should be prioritized for the application of PREMs where the end user is measuring change over time. Assessing measurement error/agreement of PREMs is important to understand the clinical relevancy of PREM scores used in a health care evaluation capacity.
Topics: Adult; Aged; Aged, 80 and over; Cross-Sectional Studies; Female; Humans; Male; Middle Aged; Patient Reported Outcome Measures; Patient Satisfaction; Reproducibility of Results; Surveys and Questionnaires
PubMed: 31218671
DOI: 10.1111/1475-6773.13187 -
Nutrients May 2022Various neurocognitive and mental health-related conditions have been associated with the gut microbiome, implicating a microbiome-gut-brain axis (MGBA). The aim of this... (Review)
Review
BACKGROUND
Various neurocognitive and mental health-related conditions have been associated with the gut microbiome, implicating a microbiome-gut-brain axis (MGBA). The aim of this systematic review was to identify, categorize, and review clinical evidence supporting medicinal plants for the treatment of mental disorders and studies on their interactions with the gut microbiota.
METHODS
This review included medicinal plants for which clinical studies on depression, sleeping disorders, anxiety, or cognitive dysfunction as well as scientific evidence of interaction with the gut microbiome were available. The studies were reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.
RESULTS
Eighty-five studies met the inclusion criteria and covered thirty mental health-related medicinal plants with data on interaction with the gut microbiome.
CONCLUSION
Only a few studies have been specifically designed to assess how herbal preparations affect MGBA-related targets or pathways. However, many studies provide hints of a possible interaction with the MGBA, such as an increased abundance of health-beneficial microorganisms, anti-inflammatory effects, or MGBA-related pathway effects by gut microbial metabolites. Data for , , and indicate that the interaction of their constituents with the gut microbiota could mediate mental health benefits. Studies specifically assessing the effects on MGBA-related pathways are still required for most medicinal plants.
Topics: Anxiety; Anxiety Disorders; Gastrointestinal Microbiome; Humans; Mental Health; Plants, Medicinal
PubMed: 35631252
DOI: 10.3390/nu14102111 -
Aging and Disease Jun 2023Alzheimer's disease (AD) is a degenerative disease of the central nervous system. The pathogenesis of AD has been explained using cholinergic, β-amyloid toxicity, tau... (Review)
Review
Alzheimer's disease (AD) is a degenerative disease of the central nervous system. The pathogenesis of AD has been explained using cholinergic, β-amyloid toxicity, tau protein hyperphosphorylation, and oxidative stress theories. However, an effective treatment method has not been developed. In recent years, with the discovery of the brain-gut axis (BGA) and breakthroughs made in Parkinson's disease, depression, autism, and other diseases, BGA has become a hotspot in AD research. Several studies have shown that gut microbiota can affect the brain and behavior of patients with AD, especially their cognitive function. Animal models, fecal microbiota transplantation, and probiotic intervention also provide evidence regarding the correlation between gut microbiota and AD. This article discusses the relationship and related mechanisms between gut microbiota and AD based on BGA to provide possible strategies for preventing or alleviating AD symptoms by regulating gut microbiota.
PubMed: 37191418
DOI: 10.14336/AD.2022.1127