GUT-BRAIN AXIS

The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication
This review explains how small molecules called short‑chain fatty acids (SCFAs)—which are made by gut bacteria when they digest dietary fiber—play a key role in connecting your gut and your brain. These SCFAs (mainly acetate, propionate, and butyrate) impact metabolism, hormones, and the immune system. Growing evidence shows they influence brain function and behavior through the gut‑brain axis, affecting inflammation, stress responses, and mental health. The authors propose that understanding SCFAs better could help develop new treatments for brain-related conditions such as depression or neurodegenerative diseases, by targeting gut microbes or their byproducts

The Brain-Gut-Microbiome Axis
This article explains how the brain, gut, and gut microbiome (the community of microbes in the digestive system) are closely connected and constantly communicate with each other. This communication happens through nerves (like the vagus nerve), hormones, and immune system signals. When this brain–gut–microbiome axis is disrupted—by stress, diet, infection, or other factors—it can affect both mental and physical health. Problems in this system have been linked to conditions like irritable bowel syndrome (IBS), anxiety, depression, and even Parkinson’s disease.

The brain-gut axis in abdominal pain syndromes
This review explains how the brain and digestive system talk to each other, especially in conditions like irritable bowel syndrome (IBS) and functional abdominal pain. Normally, the gut sends signals to the brain (about digestion, fullness, discomfort), and the brain responds by helping regulate gut functions. But in people with abdominal pain syndromes, this communication can get messed up: they may overly feel gut signals, misinterpret them, and have stronger emotional or stress reactions. Changes may happen both in the gut, in nerves going to the brain, and in brain areas that process pain, making symptoms worse. Understanding this system offers ideas for treatments that target not just the gut, but also nerves, brain, and stress/emotional factors.

Gut over Mind: Exploring the Powerful Gut-Brain Axis
This article reviews recent research on the connection between the gut microbiome and brain function. It explains that the gut hosts diverse microorganisms that influence digestion, metabolism, immunity, and mental health. Probiotics and other interventions that regulate gut bacteria can affect brain processes, mood, and cognitive function. The review highlights how understanding the gut-brain axis could lead to strategies for improving both physical and mental health through dietary or microbial modulation.

The Vagus Nerve at the Interface of the Microbiota-Gut-Brain Axis
The paper explains that communication between the gut microbiota and the brain happens not just chemically or hormonally, but also via the Vagus nerve — a major part of the parasympathetic nervous system. It argues that microbial metabolites and signals from gut microbes influence the vagus nerve (via gut‑endocrine cells or directly), which then sends information to the central nervous system. That signaling can shape immune responses, gut barrier integrity and inflammation, and influence brain processes and mental‑health outcomes. Stress, which suppresses vagus‑nerve tone, may disrupt this microbiota–gut–brain communication; by contrast, improving vagal activity (for example through vagus‑nerve stimulation) could help restore gut–brain balance, offering potential therapeutic avenues for gut or brain disorders.

The Enteric Nervous System and Its Emerging Role as a Therapeutic Target
The paper reviews how the Enteric Nervous System (ENS) — the network of neurons embedded in the gut — plays a central role connecting gut health to broader physiology. It describes how the ENS governs gut motility, secretion, barrier functions and interacts with immune and microbial signals. Disruptions to ENS structure or function may contribute to gastrointestinal diseases, and the authors propose that targeting the ENS could offer new therapeutic strategies for gut disorders.

Does Seratonin in the intestines make you happy?
The article explores how most of the serotonin in the human body is produced in the gut by specialized intestinal cells (not the brain) and describes how this “peripheral” serotonin regulates functions of the gastrointestinal tract — such as digestion and excretion — rather than directly influencing mood or happiness in the brain.

Vagus Nerve as Modulator of the Brain–Gut Axis in Psychiatric and Inflammatory Disorders
The authors describe how the Vagus nerve — a major nerve linking the brain and gut — plays a central role in what’s known as the gut–brain axis. They explain that signals from the gut (including those shaped by gut microbes, immune activity, digestion, and the gut’s own nervous system) travel via the vagus nerve to the brain, influencing mood, stress responses, inflammation and overall mental health. The paper argues that impairments or imbalances in this gut–brain communication could contribute to psychiatric or inflammatory disorders, and that treatments targeting the vagus nerve (such as vagus‑nerve stimulation, or lifestyle practices that boost vagal tone, like controlled breathing or meditation) may hold therapeutic potential.

Growing up in a Bubble: Using Germ-Free Animals to Assess the Influence of the Gut Microbiota on Brain and Behavior
The review describes how animals raised completely free from microbes (germ‑free animals) demonstrate major changes in brain development, stress response, behaviour and physiology — compared with animals with a normal microbiota. It shows that the presence of gut microbes is critical for normal stress reactivity, anxiety‑like behaviours, social behaviour, cognition, blood‑brain barrier integrity, immune function, and gut physiology.

Microbiota–gut–brain axis and its therapeutic applications in neurodegenerative diseases
The review explains how the gut microbiota communicates with the brain through the immune system, neurotransmitters, hormones, and glial cells, forming the microbiota–gut–brain axis. Dysbiosis can contribute to neurodegenerative diseases by affecting inflammation, blood–brain barrier integrity, and neuronal health. Evidence suggests interventions like probiotics, prebiotics, or fecal‑microbiota transplantation could modulate the gut microbiome to protect brain function, though more research is needed to develop practical therapies.

Restoring Balance: The Role of Omega-3 Polyunsaturated Fatty Acids on the Gut–Brain Axis and Other Interconnected Biological Pathways to Improve Depression
The review argues that omega‑3 polyunsaturated fatty acids (n‑3 PUFAs), especially EPA and DHA, may help improve depression by influencing multiple body systems at once — including the gut–brain axis. It suggests that n‑3 PUFAs can shape the gut microbiota, strengthen the intestinal barrier, reduce inflammation, support healthy neural membranes and synaptic signalling, regulate stress hormone responses, and decrease oxidative stress — all of which together may support mood, brain function and recovery from depressive symptoms.

Vagus Nerve as Modulator of the Brain–Gut Axis in Psychiatric and Inflammatory Disorders
This review argues that the Vagus nerve plays a central role in the communication network between the gut and the brain — often called the “gut–brain axis.” The nerve carries information from the gut to the brain (and vice versa), helping regulate digestion, immune response, inflammation, mood and stress. Because of its influence on immune signalling and brain chemistry, the authors suggest that targeting vagus‑nerve activity (for example via nerve stimulation, breathing exercises or meditation) could help treat psychiatric disorders (like depression or PTSD) as well as gut‑related inflammatory conditions.

Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour
The review describes how the community of microbes living in the gut can influence brain function and behaviour. Research in animals — including germ‑free or antibiotic‑treated models — shows that changing gut microbiota composition affects stress responses, anxiety, mood, cognition and pain perception via a network of neural, immune and hormonal pathways. The authors suggest the existence of a “microbiota–gut–brain axis” and propose that altering the gut microbial community may be a promising direction for developing new treatments for central nervous system disorders.

Enterochromaffin Cells Are Gut Chemosensors that Couple to Sensory Neural Pathways
The study shows that special cells in the gut lining called Enterochromaffin cells act like sensors. They detect nutrients, microbes, or inflammation and send signals to nerves using serotonin. This means the gut can “talk” to the brain and nervous system directly, helping explain how what happens in the gut — like diet or microbes — can affect sensations, mood, and brain function.

Signalling cognition: the gut microbiota and hypothalamic-pituitary-adrenal axis
This article explains that there is a two-way connection between the bacteria living in our gut and the main stress response system in our bodies called the hypothalamic-pituitary-adrenal axis or HPA axis. The gut microbiota help send chemical and nerve signals that can affect how the brain handles stress, learning, memory, and thinking. The HPA axis releases hormones like cortisol when we are stressed, and these hormones also influence the gut environment. Research in animals shows that changes in gut microbes can change stress responses and brain function, and early human studies hint at a similar influence in people. Scientists are still working to understand all the exact mechanisms, but the review highlights that gut microbes and the body’s stress systems are closely linked and important for cognitive health.

The Gut-Brain Axis: Influence of Microbiota on Mood and Mental Health
This article explains that the gut-brain axis is the communication system between the gut and the brain that uses nerves, hormones, the immune system, and other signals. The gut microbiota (the bacteria and other microbes in the gut) influence mood, thinking, and stress responses by interacting with this network. Changes in gut bacteria are linked with anxiety, depression, autism, irritable bowel syndrome, and brain development in early life, and diet also affects these connections. Research shows that gut microbes can alter hormones and brain chemicals, and stress can change the balance of those microbes, so the health of the gut community plays an important role in emotional and cognitive health.

Gut microbiota dysbiosis induces neuroinflammation in major depressive disorders: mechanisms targeting the gut-brain axis
This article reviews evidence showing that when the community of microbes in the gut becomes imbalanced it can trigger inflammation in the brain that is linked with major depressive disorder, and it explains some of the biological ways this happens through the gut–brain axis. It highlights that this inflammation involves activation of immune cells in the brain called microglia and pathways like P2X7R and NLRP3 that can damage neurons, and that changes in gut microbes can influence these processes. Because inflammation is increasingly seen as part of how depression develops, understanding the ways gut bacteria, immune signals, and stress responses interact might help find better ways to treat depression.

Gut microbiota’s effect on mental health: The gut-brain axis
This article explains that the gut-brain axis is a two-way communication system linking the community of microbes in our intestines with the central nervous system, and that when this community becomes unbalanced (called dysbiosis) it can lead to inflammation and contribute to common mental health problems such as depression and anxiety. It describes how signals from microbes, immune responses, hormones, and nerves travel between the gut and the brain, affecting stress pathways and mood regulation, and it highlights early evidence that probiotics might help restore balance in the gut and reduce symptoms by lowering inflammation. The review emphasizes that gut microbial health interacts with brain function, stress responses, and emotional wellbeing, and that targeting the microbiome could become part of future treatments for mental health disorders.

Stress & the gut-brain axis: Regulation by the microbiome
This article explains that the gut–brain axis is a two-way connection between the community of microbes in the gut and the brain that plays a major role in how the body responds to stress. It describes how signals travel through nerves like the vagus nerve, hormones, immune responses, metabolism of nutrients, and chemicals made by gut bacteria that influence emotion, behaviour, and stress physiology. Studies in animals show that changes early in life to the gut microbes can have lasting effects on stress responses and behaviour and that altering the microbiota through diet, probiotics, or prebiotics can change stress-related behaviours and biological stress responses. While the evidence is strongest in animal models, the review suggests that this gut microbiome links with anxiety, depression, irritable bowel syndrome, and stress-related conditions and that targeting the gut microbes might help positive mental health outcomes.