The gut–brain connection is the constant, two-way communication system between your digestive tract and your nervous system. It sends updates to your brain through the vagus nerve, hormones, and chemical messengers.
The gut also communicates through your immune system. When the gut lining is irritated or inflamed, immune signals can influence how your brain regulates stress, energy, and mood.
This connection matters because it helps explain why stress can hit your stomach and why chronic digestive problems can feel emotionally draining. Gut distress can send “danger” signals, making you feel more anxious, on edge, or experience brain fog. For some people, stress worsens gut symptoms, and gut symptoms worsen symptoms of mental health conditions [1].
Supporting the gut–brain connection usually means addressing both your digestive tract and mental health through nourishing meals, high-quality sleep, stress regulation, and targeted interventions to heal your gut.
How the Gut Microbiome Influences Mood and Mental Health
Gut dysbiosis means the gut microbiome is out of balance, characterized by reduced microbial diversity, fewer beneficial microbes, and overgrowth of harmful or inflammatory bacteria.
Researchers consistently link gut dysbiosis to changes in mood and stress responses through the gut–brain axis. It’s often bidirectional, meaning mental stress can disrupt the gut, and gut disruption can worsen mental symptoms [2].
Poor gut health causes inflammation throughout the body, sometimes affecting neuroinflammation, stress sensitivity, and symptoms tied to depression [3].
One of the ways the gut communicates with the brain is through endocrine (hormonal) signals. These signals can influence sleep, motivation, emotional regulation, and stress response. People who suffer from gut health problems such as IBS, Crohn’s disease, and leaky gut syndrome often report increased mental health symptoms, such as [4]:
- Impact on Mood: Low mood, emotional numbness.
- Anxiety: Heightened stress sensitivity, rumination, and physical anxiety sensations.
- Sleep: Poor gut health can impact sleep, which worsens chronic stress, gut function, and anxiety/depression symptoms.
The Vagus Nerve: Understanding The Communication Path Between The Gut and Brain
The vagus nerve is the largest nerve in the parasympathetic nervous system, running from the brain to the digestive tract and helping regulate functions such as heart rate, breathing, swallowing, and digestion.
In the gut, vagal signaling supports motility (how food moves), secretion, and coordination of digestive processes, and it helps the nervous and immune systems “talk” during irritation or inflammation.
In the brain, the vagal nerve can influence stress, mood, and emotional regulation by modulating networks involved in threat detection and calming responses. This is often why people feel anxiety in the stomach during times of chronic stress [5].
When vagal tone (how effectively the vagus nerve helps you shift into recovery mode) is lower, often associated with ongoing stress, poor sleep, illness, or chronic inflammation, people may be more prone to anxiety or low mood.
9 Signs Your Gut May Be Affecting Your Mental Health
- Anxiety that spikes after eating, especially after specific foods with sugars or preservatives, or large meals
- New or worsening irritability or low mood during digestive flares
- Feeling restless, tense, on edge, alongside bloating, reflux, or cramps
- Brain fog, trouble focusing, or feeling mentally “slowed” correlates with constipation/diarrhea
- Trouble falling asleep, waking up at night, paired with heartburn, nausea, or stomach discomfort
- Frequent bloating, gas, or abdominal pain alongside heightened stress sensitivity
- Alternating constipation and diarrhea, or urgent bowel movements during stressful moments
- Cravings for sugar/ultra-processed foods that rise with mood dips and digestive irregularity
- Feeling more emotionally stable on days your digestion feels normal
Best Foods for Gut Health That May Support Better Mental Health
Food can’t replace mental health care, but it can support the gut–brain connection by encouraging the growth of beneficial microbes, reducing inflammation, and stabilizing blood sugar [6].
- Yogurt or kefir: Fermented probiotics that can support microbial balance.
- Kimchi or sauerkraut: Fermented veggies that add beneficial bacteria.
- Fatty fish (salmon, sardines, trout): Rich in omega-3s linked to brain and inflammation support.
- Beans and lentils: High in fiber/prebiotics that feed good gut bacteria and support steady energy.
- Oats: Gentle soluble fiber that supports gut lining and helps regulate digestion.
- Berries (blueberries, raspberries, strawberries): Polyphenols that nourish beneficial microbes.
Heal Your Gut with Functional Medicine at Harper Clinic, Utah
Harper Clinic supports gut health restoration and recovery through a functional medicine approach that addresses the root causes of gut imbalance. Our team creates personalized treatment plans incorporating targeted nutrition, lifestyle modifications, and advanced therapies to heal the gut lining, reduce inflammation, and restore neurotransmitter balance.
Our focus on individualized care empowers clients to rebuild gut health while supporting overall physical and mental well-being, helping patients achieve sustainable healing and improved quality of life.
Sources
[1] Tompa, R. 2025. The gut-brain connection: What the science says. Stanford Medicine.
[2] Wang, G. et al. Gut Microbiota Dysbiosis: Pathogenesis, Diseases, Prevention, and Therapy. MedComm (2020). 2025 Apr 18;6(5):e70168. doi:
[3] Wakefield, S. et al. Gut microbiota’s effect on mental health: The gut-brain axis. Clin Pract. 2017 Sep 15;7(4):987.
[4] Appleton, J. The Gut-Brain Axis: Influence of Microbiota on Mood and Mental Health. Integr Med (Encinitas). 2018 Aug;17(4):28-32.
[5] Cleveland Clinic. 2022. Vagus Nerve.
[6] Johns Hopkins. 5 Foods to Improve Your Digestion.