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The Microbiota-Gut-Brain Axis in Neuropsychiatric Disorders: Pathophysiological Mechanisms and Novel Treatments.
Kim, YK, Shin, C
Current neuropharmacology. 2018;16(5):559-573
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Plain language summary
The connection between the microbiome in the gut and the brain is known as the gut-brain axis and may have implications in the development and treatment of brain disorders. This narrative review paper aimed to summarise the gut-brain axis and studies surrounding the use of gut microbiota in treatment for brain disorders. The authors first highlighted that the gut microbiota is individual and varies depending on the age of the host, with full development around the age of 3 years old. Diet, infections, the use of antibiotics and stress can all affect the gut-microbiota in what is termed dysbiosis. Studies in animals indicate that the gut-brain axis may be bidirectional with either aspect affecting the other. Stress may cause dysbiosis, affecting both digestion and the immune system. In turn the gut microbiota may affect the brain through the immune system, modulation of nerves, and through the production of signalling molecules. Several diseases of the brain may be influenced by the gut microbiota. Mood disorders, brain degeneration and childhood brain development disorders were all highlighted as having potential relationships with dysbiosis. The use of probiotics in chronic fatigue syndrome, schizophrenia, brain function and autism spectrum disorder were reviewed with positive results in chronic fatigue syndrome and brain function, however studies are lacking. It was concluded that gut microbiota may directly or indirectly affect brain disorders, however the role of probiotics as a treatment needs more research. This study could be used by healthcare professionals to understand the potential role of the gut microbiota in brain disorders.
Abstract
BACKGROUND The human gut microbiome comprise a huge number of microorganisms with co-evolutionary associations with humans. It has been repeatedly revealed that bidirectional communication exists between the brain and the gut and involves neural, hormonal, and immunological pathways. Evidences from neuroscience researches over the past few years suggest that microbiota is essential for the development and maturation of brain systems that are associated to stress responses. METHOD This review provides that the summarization of the communication among microbiota, gut and brain and the results of preclinical and clinical studies on gut microbiota used in treatments for neuropsychiatric disorders. RESULT Recent studies have reported that diverse forms of neuropsychiatric disorders (such as autism, depression, anxiety, and schizophrenia) are associated with or modulated by variations in the microbiome, by microbial substrates, and by exogenous prebiotics, antibiotics, and probiotics. CONCLUSION The microbiota-gut-brain axis might provide novel targets for prevention and treatment of neuropsychiatric disorders. However, further studies are required to substantiate the clinical use of probiotics, prebiotics and FMT.
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Dietary and nutrition interventions for the therapeutic treatment of chronic fatigue syndrome/myalgic encephalomyelitis: a systematic review.
Campagnolo, N, Johnston, S, Collatz, A, Staines, D, Marshall-Gradisnik, S
Journal of human nutrition and dietetics : the official journal of the British Dietetic Association. 2017;30(3):247-259
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This systematic review evaluated the evidence available for dietary and nutritional interventions for chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). 17 studies met the inclusion criteria the authors used. Notably, studies that used multi-treatments were excluded from this review. The quality of the studies varied, but two thirds were considered to be of high quality. None of the trials reported a dietary intake method at start and end of the trial period, so dietary changes alongside the intervention may have influenced the results. A variety of scales were used to measure improvement of symptoms, making it difficult to compare studies, and study designs limited recruitment to those CFS/ME sufferers who were well enough to attend a clinic/hospital. Positive results were found for nicotinamide adenine dinucleotide hydride (NADH), with and without Co-enzyme Q10, polyphenol rich chocolate and probiotics, however, studies were either of short duration or had small samples sizes, and for most interventions there was only one study. The authors conclude that, whilst there is insufficient evidence for the general prescription of supplements or elimination diets for CFS/ME patients, such interventions may be considered on an individual basis.
Abstract
BACKGROUND Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is characterised by unexplained fatigue for at least 6 months accompanied by a diverse but consistent set of symptoms. Diet modification and nutritional supplements could be used to improve patient outcomes, such fatigue and quality of life. We reviewed and discussed the evidence for nutritional interventions that may assist in alleviating symptoms of CFS/ME. METHODS Medline, Cinahl and Scopus were systematically searched from 1994 to May 2016. All studies on nutrition intervention were included where CFS/ME patients modified their diet or supplemented their habitual diet on patient-centred outcomes (fatigue, quality of life, physical activity and/or psychological wellbeing). RESULTS Seventeen studies were included that meet the inclusion criteria. Of these, 14 different interventions were investigated on study outcomes. Many studies did not show therapeutic benefit on CFS/ME. Improvements in fatigue were observed for nicotinamide adenine dinucleotide hydride (NADH), probiotics, high cocoa polyphenol rich chocolate, and a combination of NADH and coenzyme Q10. CONCLUSIONS This review identified insufficient evidence for the use of nutritional supplements and elimination or modified diets to relieve CFS/ME symptoms. Studies were limited by the number of studies investigating the interventions, small sample sizes, study duration, variety of instruments used, and studies not reporting dietary intake method. Further research is warranted in homogeneous CFS/ME populations.