Summary of a research paper published in the journal Cell<\/i> in 2025, summarizing the latest research and scientific findings regarding the impact of gut bacteria on the brain and mental health.<\/b><\/p>\n
It is well known that there are trillions of microorganisms living inside the human body that play a major role in our health. The gut microbiome refers to the collective genome of the microorganisms residing in the intestines. Developments in sequencing technologies have demonstrated its crucial role in immune system maturation, neuroinflammation, and neurobehavioral traits.<\/p>\n
These interactions that bring together immunity, the nervous system, and the digestive system are known as the gut-microbiota-immune-brain axis, deeply connected to the enteric nervous system (ENS). The ENS is sometimes described as a major arm of the autonomic nervous system, which represents all the processes the brain regulates outside our conscious will, such as breathing, sweating, and digestion. The vagus nerve is one of the primary communication pathways between the gut and the brain. Scientists have learned from clinical cases that cutting or stimulating the vagus nerve affects mood on one hand, and gut function and immune responses on the other. Animals that undergo a vagotomy (cutting of the vagus nerve) exhibit clear immune dysregulation. Additionally, a decrease in specific types of gut bacteria (Prevotella<\/i>) has been observed in humans who have undergone a vagotomy.<\/p>\n
Another way gut bacteria interact with the brain is by producing and responding to serotonin. They also produce and respond to other substances that influence brain function, such as gamma-aminobutyric acid (known as GABA, which contributes to calmness and relaxation), as well as dopamine, norepinephrine, and indoles (such as tryptophan). Serotonin, which is sometimes colloquially referred to as the “happiness hormone” in popular culture, is produced at a rate of up to 95% within the digestive system rather than the brain, and beneficial gut bacteria contribute significantly to its synthesis.<\/p>\n
Regarding psychological and brain-related aspects and their direct connection to gut bacteria, scientists have found a correlation between certain intestinal inflammations and autism spectrum disorder (ASD), Parkinson’s disease, and Alzheimer’s disease\u2014specifically inflammations driven by immune cells known as neutrophils. These inflammatory processes impact the health of the gut microbiota and contribute to complex disorders, demonstrating the role of gut bacteria in conditions like Parkinson’s and Alzheimer’s.<\/p>\n
Disruptions in gut bacteria also manifest in conditions such as major depressive disorder (MDD), where the count of certain immune cells alters, consequently shifting the composition and types of bacteria present in the gut. Certain species drop severely in cases of untreated depression. Furthermore, in animal experiments, fecal microbiota transplantation (FMT) from depressed individuals induced depression-like behavior in the recipients. Conversely, certain types of beneficial bacteria (including L. helveticus<\/i>, Bifidobacterium longum<\/i>, and L. plantarum<\/i>) have shown positive effects on the severity of depression. Transplanting the fecal microbiota of individuals with social anxiety disorder into mice resulted in social hypersensitivity, a decline in T cell patterns, and alterations in gut bacteria as well.<\/p>\n
Scientists have observed highly distinct patterns in other conditions where beneficial bacteria were not initially expected to play a role, such as schizophrenia, autism spectrum disorder, and attention deficit hyperactivity disorder (ADHD). These patterns are characterized by the increase of a specific type of beneficial gut bacteria or the decrease of another. Even with multiple sclerosis (MS), it was noted that transplanting the fecal microbiota of human patients into germ-free mice led to the development of experimental autoimmune encephalomyelitis (EAE) in those mice.<\/p>\n
Source:<\/b> O\u2019Riordan, Kenneth J., et al. “The gut microbiota-immune-brain axis: Therapeutic implications.” Cell Reports Medicine<\/i> 6.3 (2025).<\/p>\n
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Summary of a research paper published in the journal Cell in 2025, summarizing the latest research and scientific findings regarding the impact of gut bacteria on the brain and mental health. It is well known that there are trillions of microorganisms living inside the human body that play a major role in our health. The […]<\/p>\n","protected":false},"author":1,"featured_media":267831,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[5325,5254],"tags":[],"authorship_type":[5108],"class_list":["post-267833","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-medicine","category-psychology","authorship_type-5108"],"yoast_head":"\n