Please enable JavaScript.

Coggle requires JavaScript to display documents.

The Role of Gut Microbiota in Anxiety, Depression, and Other Mental…

- - - - Mental disorders can influence the study, work, and normal life of patients, and lead to suicide in severe situations.
      - In 2019, the number of individuals suffering from mental disorders was estimated to be close to 970 million
      - On the other hand, the gut microbiota and its metabolites have a significant influence on preserving the overall health of the host; gut microbiota dysbiosis has been reported to be associated with the occurrence and development of several chronic metabolic diseases, such as obesity, diabetes mellitus, and cancers
      - It was reported that the gut microbiota could influence the brain and mental health in several ways, such as the vagus nerve, microbial regulation of neuro-immune signaling, microbiota-mediated tryptophan metabolism, microbial control of neuroendocrine function, and microbial production of neuroactive compounds
      - The effects of natural products against mental disorders have become a research hotspot in the fields of food science, nutrition, psychology, and psychiatry in recent years
    - - The composition of gut microbiota is complex; some microorganisms may protect mental health, while others may be related to the onset and development of mental disorders
        
        Bipolar Disorder
        
        Several compelling lines of evidence linked the gut microbiome to bipolar disorder. For instance, a study showed that bipolar disorder patients had a reduction in gut microbiota diversity, with more Clostridiaceae and Collinsella
        
        Additionally, a cross-sectional study indicated that Flavonifractor was associated with bipolar disorder (odds ratio (OR), 2.9; 95% CI, 1.6–5.2) [41]. Another cross-sectional study found that Faecalibacterium significantly decreased in bipolar disorder patients
        
        Depression
        
        Studies showed that gut microbiome dysbiosis was associated with the occurrence and development of depression
        
        A study found obvious differences of fecal microbiota composition in four phyla as well as in the abundances of 16 bacterial families between healthy individuals and major depressive disorder (MDD) patients
        
        Another study found a relative reduction in the alpha diversity of gut microbiota in patients with current depressive episodes [33]. Additionally, a study based on a large microbiome population cohort showed that Dialister and Coprococcus spp. were decreased in patients with depression
        
        Anxiety
        
        It is indicated that certain gut microbiota are correlated with anxiety.
        
        A study found that the abundance of Prevotella was increased, while the Firmicutes/Bacteroidetes ratio and the abundance of Faecalibacterium spp. were significantly reduced in individuals with social exclusion
        
        Moreover, a study of 198 Spanish individuals found that patients with anxiety had lower Simpson’s diversity . Additionally, patients with generalized anxiety disorder (GAD) had lower microbial richness and diversity, as well as reduced levels of Firmicutes spp. and microbiota that produce SCFAs, but more Fusobacteria and Bacteroidetes
        
        Autism Spectrum Disorder
        
        Research has shown that the composition and abundance of gut microbiota differ between individuals with ASD and those without the disorder.
        
        For example, a study found that children with Pitt–Hopkins syndrome (a severe ASD) had a higher relative abundance of Clostridium bolteae than their unaffected family members
        
        Another study indicated that higher levels of Clostridium paraputri, Clostridium bolteae, and Clostridium perfringens were found in the feces of Egyptian ASD children. In addition, Clostridium diffiicile and Clostridium clostridiioforme were only found in ASD children, while Clostridium tertium was only found in normal children
        
        Schizophrenia
        
        Mounting evidence indicated that schizophrenia was associated with gut microbiota dysbiosis.
        
        For instance, a case-control study showed that gut microbiome dysbiosis was found in schizophrenia patients
        
        A cross-sectional study found that several gut bacteria could only be found in healthy participants, but were missing in patients with schizophrenia, such as Haemophilus
        
        However, another study found a positive correlation between the level Haemophilus abundance and negative symptoms of schizophrenia [47]. The discrepancy between the two studies might be associated with the participants having different types of schizophrenia
    - - Many dietary components have been shown to exert protective effects against mental disorders through regulating gut microbiota, such as probiotics, prebiotics, postbiotics, fruits, vegetables, and spices,
        
        Probiotics
        
        Probiotics have become a hotspot in the research fields of foods, nutrition, biology, and medicine, and can be used to prevent and manage several diseases, such as constipation, obesity, and cardiovascular disease
        
        Prebiotics and Postbiotics
        
        The studies indicated that prebiotics and postbiotics could also be potential for the prevention and management of mental disorders, such as anxiety, depression, ASD, and schizophrenia.
        
        It was reported that dietary fibers could improve the relationship between gut microbiota and the central nervous system in schizophrenia patients through regulating gut microbiota
        
        Dairy Products
        
        Dairy products are important components of both traditional and modern diets, and have a variety of health benefits. A double-blinded RCT based on 82 depressive patients with constipation found that the intervention of a fermented dairy beverage containing Lacticaseibacillus paracasei strain
        
        Shirota for 9 weeks increased beneficial bacteria (e.g., Adlercreutzia, Megasphaera and Veillonella), but decreased harmful bacteria (e.g., Rikenellaceae_RC9_gut_group, Sutterella and Oscillibacter) in the gut, and ultimately alleviated constipation and potentially depressive symptoms
        
        Spices
        
        Spices have a long history of being used as both food flavorings and traditional medicine, which possess many bioactive functions, such as anti-inflammatory, antibacterial, antifungal, and anticancer activities [119,120]. Moreover, the preventive and therapeutic effects of spices on mental disorders have received increasing attention
        
        Collectively, spices and their components (such as Zanthoxylum bungeanum, curcumin, and capsaicin) showed protective effects against anxiety and depression via regulating gut microbiota
    - - The gut microbiota and its metabolites could play an important role in mental health through the microbiota–gut–brain axis.
        
        The composition and abundance of gut microbiota, especially Firmicutes and Bacteroidetes, were associated with several mental disorders, such as anxiety, depression, bipolar disorder, ASD, and schizophrenia.
        
        At present, most studies about gut microbiota with mental disorders focused on the genus level, and more studies on gut microbiota should be carried out at the species level in the future, because the different species in the same genera could have different effects (even the opposite function) on mental disorders
        
        Furthermore, due to the potential significant differences in the composition of the gut microbiome among individuals, it is crucial to accurately identify the changes of featured microbes that occur in each individual with mental disorders, which is important for personalized treatment of mental disorders through targeting gut microbiota