Gut-Brain Axis and Anxiety: Why Stress Can Affect Your Stomach

Have you ever felt nauseated before an important conversation, lost your appetite when you're stressed, or experienced stomach cramps when anxiety kicks in? These aren't imagined symptoms. They are examples of the very real connection between anxiety, your gut and your brain.

This is why the gut-brain axis model is important: it is a bi-directional communication channel between the brain, the nervous system, the gut, and the microbiome. It is composed of the nerves, hormones, immune system, and microbial metabolites that can send messages from the gut to the brain, and vice versa.

That's why anxiety can cause stomach problems such as nausea, cramping, bloating, diarrhea, constipation and changes in appetite. It's also why digestive disorders such as irritable bowel syndrome (IBS) frequently overlap with anxiety.

Now researchers are focusing on the gut brain axis and how stress, trauma and permeability relate to mental health, and on whether things like diet, probiotics, stress management and other interventions can impact this relationship.

We often hear from customers at Village Green Apothecary asking about the relationship between their gut health and their mental health. Here's what science says about the gut-brain axis, and what research is ongoing.

What Is the Gut-Brain Axis?

The gut-brain axis is a two-way communication network linking your digestive tract to your brain.

It’s more like a network, not a pathway.

Signals can move through many linked systems such as:

• The vagus nerve, as well as other nervous-system routes

• The hypothalamic-pituitary-adrenal (HPA) stress-response system

• Hormones and neurotransmitters

• Immune and inflammatory signaling

• The gut microbiome

• Microbial metabolites such as short-chain fatty acids

• Tryptophan and serotonin-related pathways

A 2024 review, Gut-Brain Axis: Role of Microbiome, Metabolomics, Hormones, and Stress in Mental Health Disorders, describes the gut-brain axis as a complex network involving microbial, metabolic, hormonal and stress-related pathways.

This communication goes both ways.

Stress and anxiety can change digestive function. At the same time, signals originating in the gastrointestinal tract and gut microbiome may influence the nervous system and brain.

Can Anxiety Cause Stomach Problems?

Yes. Anxiety can lead to gastrointestinal issues, and in some cases the GI symptoms are the initial ones that people become aware of.

Common anxiety stomach symptoms can include:

• Nausea or a "knotted stomach"

• Abdominal discomfort or cramping

• Bloating and gas

• Diarrhea

• Constipation

• Changes in appetite

• Feeling full quickly

• Increased urgency to have a bowel movement

Stress activates physiological responses designed to help the body deal with a perceived challenge. Those changes don't stop at the brain.

The ANS also changes digestive motility, sensitivity and secretion, which may explain why we experience anxiety in our stomach.

That isn’t to say that any digestive symptoms you experience are related to anxiety. If your GI symptoms are chronic or unexplained, they should be properly evaluated.

Why Does Anxiety Make Your Stomach Hurt?

If you’re worried or in a stressful situation, your nervous system will change how resources are distributed across your body.

Altered autonomic activity and stress hormones may affect gastric motility and the intensity of gut sensations.

In some cases, stress may make things move faster and cause diarrhea or urgency. In other cases, it can slow digestion down and cause constipation or bloating.

The digestive tract can also become more sensitive to normal sensations.

This explains why a person might have real stomach pain due to anxiety without any physical explanation.

The Vagus Nerve and the Gut-Brain Connection

One of the major communication pathways between the gut and brain is the vagus nerve.

The vagus nerve extends from the brainstem to organs throughout the body, including the digestive tract. It carries information in both directions and plays an important role in parasympathetic nervous-system activity.

This is one reason breathing exercises have become an area of interest in stress management.

Slow breathing appears to be able to affect vagally-mediated heart-rate variability, which measures parasympathetic nervous system activity.

That doesn't mean a few slow breaths will "reset" the vagus nerve or cure anxiety. But breathing exercises are a simple, low-cost way to influence autonomic regulation and may be useful alongside other stress-management strategies.

The Gut Microbiome and Anxiety

Your digestive tract is home to trillions of microorganisms collectively known as the gut microbiome.

These microbes interact with the body in a number of ways. They can help digest certain components of our diet, they can produce metabolites, and they can interact with our immune system and participate in metabolic processes that may play a role in gut-brain signaling.

Researchers have found differences in gut microbiota composition among people with anxiety and depression, although this does not prove that particular bacteria cause these conditions.

A systematic review of the gut microbiota in anxiety and depression found differences in microbial composition associated with these conditions, while also highlighting considerable variation between studies.

The next phase of research will be to answer another, perhaps even more difficult question: If we change the microbiome, does that have any real impact on anxiety or mood?

What About Serotonin and the Gut?

You may have heard that "90% of serotonin is made in the gut."

There is some truth to that, but it is often an oversimplification.

About 90% or more of the serotonin in our body is produced in our gut, mainly in specialized cells called enterochromaffin cells.

However, serotonin produced in the gut does not simply cross the blood-brain barrier and become serotonin in the brain.

Serotonin also plays a role locally in the gut, for example in regulating gut function. The gut microbiome may affect these serotonin-related pathways indirectly, via metabolites, immune signalling or tryptophan metabolism.

You can read more about this relationship in this review of the gut-brain axis and serotonin.

So the gut-serotonin connection is real – but it's more complicated than saying that making more serotonin in your gut automatically improves your mood.

Stress, Inflammation and the Gut-Brain Axis

Stress may affect the gastrointestinal tract by way of various mechanisms.

Stress activates the HPA axis and cortisol, whereas autonomic signal changes may impact gut motility and sensitivity.

Stress, the microbiome, intestinal permeability, and immune/inflammatory signaling are all being studied by researchers in an effort to better understand how they interact.

A 2024 review, Mind, Mood and Microbiota-Gut-Brain Axis in Psychiatric Disorders, describes the microbiota-gut-brain axis as closely interconnected with stress and inflammatory pathways.

This is an evolving field. Researchers are still working to determine which microbiome changes contribute to disease, which are consequences of disease, and which may simply occur alongside it.

IBS and Anxiety: A Classic Gut-Brain Connection

IBS and anxiety are a good example of how important the gut-brain connection is.

Currently, IBS is more typically classified as a disorder of gut-brain interaction.

People with IBS can experience changes in intestinal motility and heightened sensitivity to sensations from the digestive tract. Stress and anxiety can amplify these symptoms, while chronic digestive symptoms can themselves contribute to anxiety and distress.

In other words, the relationship can work in both directions.

That doesn't mean IBS is "just stress" or "all in your head."

The symptoms are real. The nervous system and digestive system are simply much more interconnected than they were once treated in medicine.

If reflux rather than IBS is part of your picture, we've also looked at the link between acid reflux and anxiety.

Can Diet Support the Gut-Brain Axis?

One of the easiest and most effective methods for helping the microbiota of your gut as well as supporting the health of your digestive tract is through diet.

Rather than looking for one "gut-brain food," focus on dietary variety.

Foods that may help support a diverse gut microbiome include:

• Vegetables

• Fruits

• Beans and lentils

• Whole grains

• Nuts and seeds

• Other fiber-rich plant foods

• Fermented foods when well tolerated

Dietary fiber is especially notable as some gut microbes ferment fiber and release SCFAs. Scientists are currently investigating how these microbial byproducts might contribute to the health of the intestine, influence the immune system and mediate signaling from the gut to the brain.

Omega-3 fatty acids are also being investigated for their roles in brain and mental health.

For additional nutritional options, you can explore Village Green's Brain Health Support.

Do Probiotics Help Anxiety?

This is one of the most interesting – and most heavily marketed – areas of gut-brain research.

In some studies, the word psychobiotic is used to refer to a probiotic or other microbiome-based intervention that is being investigated for potential impacts on mental well-being.

Recent research is encouraging, but it isn't yet strong enough to say that probiotics treat anxiety.

A 2025 systematic review of randomized controlled trials evaluated probiotics and prebiotics in people with clinically diagnosed depression or anxiety. Researchers found some potentially beneficial results, but studies differed considerably in bacterial strains, doses, populations and treatment duration.

This is important because probiotic benefits are strain-specific. One probiotic cannot automatically be assumed to produce the same effects as another.

Probiotics will probably find a place as an adjuvant therapy for some psychiatric conditions, but they shouldn't be a substitute for current anxiety treatments.

How to Support the Gut-Brain Axis Naturally

There is no single supplement or food that "fixes" the gut-brain axis.

The best place to start is with habits that support both digestive and nervous-system health:

• Eat a varied, fiber-rich diet.

• Include fermented foods if you tolerate them.

• Eat regularly enough to meet your nutritional needs.

• Slow down during meals when possible.

• Get regular physical activity.

• Prioritize consistent sleep.

• Limit excessive alcohol.

• Use stress-management strategies that work for you.

• Try slow breathing or relaxation exercises.

• Get professional help if anxiety is ongoing or causing difficulty in your life.

These aren't glamorous interventions, but they're much more important than chasing one particular "gut-brain supplement."

Supplements for Stress, Mood and Brain Health

Supplements might augment, not supplant, good nutrition, adequate sleep, stress-reduction practices, and proper medical and mental health treatment.

Depending on individual needs, our pharmacists may discuss options such as:

• Omega-3 fatty acids, which have been studied extensively for brain and cardiovascular health

• Relora, a botanical combination used for stress support

• L-5-HTP 100 mg, a serotonin precursor used in some mood-support protocols

• B vitamins, which participate in normal energy metabolism and nervous-system function

• Lion's Mane Mushroom, which is being studied for potential neurological effects

These products aren't treatments for anxiety disorders, and "natural" doesn't automatically mean appropriate for everyone.

The biggest risk of using 5-HTP is that it acts on serotonin systems, which can lead to interactions with antidepressants and other serotonergic drugs. Consult with your doctor or pharmacist before taking 5-HTP with other medications.

When Gut Symptoms and Anxiety Need More Attention

Occasional nervous stomach symptoms are common. Persistent digestive or anxiety symptoms are different.

If you experience frequent or increasingly severe GI symptoms that interfere with your day-to-day activities, please speak with your doctor.

Don’t assume any digestive symptoms like unintentional weight loss, blood in your stool, ongoing vomiting, trouble swallowing, fever, sharp belly pain or other unusual symptoms are only due to stress or anxiety.

Similarly, chronic worry, panic attacks, or altered moods warrant a proper mental health assessment and treatment.

There’s definitely a gut-brain connection, but it shouldn’t be an excuse to ignore a separate medical or mental health problem.

Key Takeaways: Gut-Brain Axis and Anxiety

• The gut-brain axis is a two-way communication network connecting the brain, nervous system, digestive tract, immune system and gut microbiome.

• When you’re anxious, your body releases a cascade of stress hormones, which can cause you to feel nauseated, have a stomach ache or cramps, feel bloated, get diarrhea, become constipated or lose your appetite.

• The vagus nerve is one important pathway involved in communication between the gut and brain.

• While most of the body’s serotonin is made in the gut, that gut serotonin doesn’t just go straight to the brain.

• The stress can also impact motility and sensitivity, as well as many other features of the gastrointestinal tract.

• The theory that IBS is a disorder of gut-brain interaction also contributes to its high comorbidity with anxiety.

• A fiber-rich, varied diet can help support the gut microbiome.

• Several trials have examined probiotics and psychobiotics for anxiety and mood. Overall, the findings are mixed with any benefit likely dependent on the exact intervention.

• This technique of slow breathing modulates the parasympathetic and vagal activity, which makes this technique an inexpensive intervention for stress management.

• These gut-health measures are not a substitute for mental-health care and should only be used as a complement to an appropriate anxiety treatment.

Frequently Asked Questions About the Gut-Brain Axis and Anxiety

Can anxiety cause stomach problems?

Yes. Anxiety can influence the autonomic nervous system and the pathways of the stress response that also regulate digestion. This may contribute to nausea, stomach ache, diarrhea, constipation, bloating, appetite changes, and other GI symptoms. Persistent GI symptoms should still be medically evaluated rather than automatically attributed to anxiety.

What does anxiety feel like in your stomach?

People describe anxiety-related stomach symptoms differently. Common experiences include nausea, "butterflies," a knotted feeling, abdominal discomfort, cramps, urgency, diarrhea, loss of appetite or increased awareness of digestive sensations.

What is the gut-brain axis?

The gut-brain axis is the bidirectional communication network between the gastrointestinal system and brain. Communication occurs through the nervous system, vagus nerve, stress hormones, immune signaling, microbial metabolites and other pathways.

Can gut health affect anxiety?

Research suggests that the gut microbiome and brain communicate through several biological pathways and that differences in gut microbiota have been observed in people with anxiety. However, researchers are still determining how much changing the microbiome can directly improve anxiety symptoms.

Do probiotics help with anxiety?

Some studies have shown some modest benefit with certain probiotics for reducing anxiety symptoms. Others have shown no such benefit. Results depend on the specific strains of bacteria used, the dosage, the specific population studied, and how long the study lasted. Currently, there isn’t enough evidence to suggest that probiotics could be a substitute for proven anxiety treatments.

What foods are good for the gut-brain axis?

A varied diet containing fiber-rich plant foods such as vegetables, fruit, legumes, whole grains, nuts and seeds can help support gut microbial diversity. Fermented foods may also be useful for some people. There isn't one food that can independently "heal" the gut-brain axis.

Why are IBS and anxiety connected?

IBS is a disorder of gut-brain interaction. In other words, signals from the brain to the digestive system or vice versa can affect bowel motility, sensitivity and symptoms. Anxiety may exacerbate gastrointestinal symptoms and persistent IBS symptoms may cause an increased level of stress or anxiety. The relationship goes both ways.

venta

PATHWAY Súper Omega-3 EC

review

$36.04 $51.48

La cubierta entérica reduce los eructos con sabor a pescado Super Omega-3 es destilado molecularmente para su pureza y contiene altas concentraciones de los ácidos grasos esenciales Omega-3 EPA y DHA (300 mg y 200 mg respectivamente). Los ácidos grasos Omega-3 son un nutriente de apoyo muy importante para la salud cardiovascular, así como para la salud cerebral y ocular. Cada cápsula blanda tiene una cubierta entérica para eliminar el olor y el regusto a pescado típicamente asociados con la ingesta de una cápsula de aceite de pescado. La cubierta entérica también protege las cápsulas blandas de ser digeridas en el estómago y permite que el aceite de pescado llegue al tracto gastrointestinal inferior para su absorción. Uso sugerido: 1 cápsula blanda 2 veces al día

Añadir al carrito

venta

PATHWAY Ultra Omega-3

No reviews

$61.79 $88.27

Los beneficios para la salud de las grasas Omega-3 en dosis altas procedentes del aceite de pescado están bien documentados en la literatura científica. Numerosos estudios demuestran los beneficios de las grasas Omega-3, EPA y DHA. El DHA es importante para la estructura y función de las membranas celulares, particularmente las del sistema nervioso. El DHA es crítico para la estructura y función cerebral normal y saludable.† El EPA se encuentra en pequeñas cantidades en el cerebro, pero es necesario para numerosas funciones reguladoras en todo el cuerpo. El EPA ayuda a mantener una respuesta inflamatoria saludable y una función cardiovascular óptima.† Los beneficios cardiovasculares de las dosis altas de Omega-3 incluyen la capacidad de mantener un latido cardíaco normal y saludable, una coagulación sanguínea normal, así como niveles saludables de triglicéridos en la sangre.Características Una sola cápsula blanda bovina proporciona 1250 mg de concentrado de aceite de pescado molecularmente destilado en forma de triglicéridos naturales. 1063 mg de ácidos grasos Omega 3 totales, que contienen 687 mg de ácido eicosapentaenoico (EPA) y 313 mg de ácido docosahexaenoico (DHA). El aceite de pescado Ultra Omega 3 es molecularmente destilado para eliminar posibles contaminantes: muy limpio y puro, libre de subproductos de pescado, sin regusto. Pescado de agua fría capturado en la naturaleza (anchoa, sardina, caballa) de origen sostenible. El aceite de pescado Ultra Omega 3 se somete a pruebas exhaustivas para cumplir con los estándares europeos y Prop65 más estrictos para metales pesados, PCB, dioxinas, microbios, pesticidas y otros compuestos no deseados. Beneficios Manera conveniente y fácil de obtener una dosis alta de ácidos grasos omega-3 en forma de triglicéridos naturales. Numerosos estudios demuestran los potentes beneficios de las grasas omega-3, en particular el EPA, para la salud cardiovascular. El EPA tiene el potencial de regular la producción de prostaglandinas que tienen un efecto beneficioso sobre los procesos inflamatorios en el cuerpo. El EPA ayuda a mantener una circulación sanguínea normal y saludable al ayudar a regular los procesos de coagulación sanguínea. El EPA ayuda a mantener un metabolismo normal y saludable del colesterol y los triglicéridos. El DHA es esencial para el desarrollo cerebral fetal e infantil normal, y apoya la función cerebral y la visión normales y saludables a lo largo de la vida. El DHA apoya la estructura de las membranas celulares, particularmente las de las células nerviosas. La estructura de la membrana de la célula nerviosa es crítica para una función saludable del sistema nervioso, particularmente la del cerebro.

Añadir al carrito

venta

PATHWAY Aceite de linaza

review

$15.83 $22.62

Hecho con lino orgánico Si estás buscando una de las mejores fuentes vegetales de ácidos grasos Omega 3 de la naturaleza —e incluso cantidades útiles de Omega-6 y Omega-9— no busques más... la semilla de lino es tu respuesta. Debido a su alto contenido de lignanos, también es una gran fuente de fibra. El aceite de linaza que usamos en nuestros productos proviene de semillas de lino cultivadas orgánicamente certificadas. Se extrae mediante prensado por expulsor a una temperatura inferior a 38 °C sin el uso de disolventes de uso común que pueden desnaturalizar el aceite. Está disponible como un delicioso aceite con sabor a nuez o en cápsulas convenientes.Uso sugerido: 5-10 cápsulas por día

Añadir al carrito

venta

PATHWAY Relora

No reviews

$23.79 $33.99

Controla la alimentación inducida por el estrés Relora® contiene dos extractos vegetales patentados en proceso de aprobación, uno de Magnolia officinalis y el otro de Phellodendron amurense. Se ha demostrado clínicamente que Relora altera significativamente los niveles hormonales asociados con la obesidad inducida por el estrés. Relora también favorece la sensación de relajación y puede ayudarte a disfrutar de un sueño más reparador. Nuestra fórmula contiene la misma dosis utilizada en los estudios clínicos.Uso sugerido: 1 cápsula 3 veces al día con las comidas

Añadir al carrito

venta

PATHWAY L-5-Htp 100 Mg

review

$14.69 $20.99

Un precursor natural de la serotoninaEl L-5-HTP es un aminoácido que desempeña un papel importante en la producción de serotonina, un neurotransmisor asociado con el bienestar emocional y la regulación del ciclo del sueño. Debido a que el estrés y una dieta deficiente pueden causar una disminución de los niveles de serotonina, la suplementación con 5-HTP puede ayudar a reponerlos. Pathway L-5-HTP 100 mg también incluye importantes cofactores, vitamina C y vitamina B6, para un apoyo mejorado. Uso sugerido: 1 cápsula diaria con las comidas

Añadir al carrito