Is Your Anxiety Really Coming From Your Gut?
The Overlooked Root of Anxiety
October is Mental Health Awareness Month, and for many people, anxiety feels like it comes out of nowhere - racing thoughts, restless sleep, irritability, or that constant hum of worry you can’t shake.
But anxiety is often not “all in your head.” It’s in your gut.
The gut and brain are in constant communication through the vagus nerve - a two-way highway of chemical and electrical messages. Your microbiome also produces neurotransmitter precursors, short-chain fatty acids, and immune signals that directly affect brain chemistry. When this system is balanced, it supports a calm, stable mood. When it’s disrupted, anxiety is one of the body’s clearest SOS signals.
At Above Health Nutrition, we consistently see four gut dynamics that directly impact anxiety and mental health.
Your Anxiety May Be Starting in the Gut
Maldigestion & Malabsorption: When the Brain Can’t Get What It Needs
At the core of mental health are neurotransmitters - serotonin, dopamine, and GABA - the brain chemicals that regulate calm, focus, and resilience. Every one of them depends on nutrients that must come from the gut.
Maldigestion means food isn’t broken down fully. Malabsorption means even when nutrients are freed, the gut lining fails to absorb them efficiently. Together, they deprive the brain of its building blocks. When protein isn’t digested well, precursors like tryptophan and tyrosine are limited. When absorption is compromised, cofactors like zinc, magnesium, iron, and B-vitamins don’t make it into circulation, and without those, neurotransmitters can’t be activated or recycled. Even fat-soluble vitamins A and D, crucial for immune balance and mood stability, are lost when bile is sluggish or the gut lining is inflamed.
Without these raw materials, neurotransmitter production slows, mood pathways falter, and the brain struggles to regulate stress. What shows up as anxiety or low mood is often the result of a gut that isn’t fueling the brain
Nutrient Deficiencies Disrupt Brain Chemistry
Low Beneficial Bacteria & Butyrate: The Microbiome–Mood Connection
The microbiome is more than a digestive aid - it’s a mood regulator. Beneficial bacteria produce short-chain fatty acids like butyrate, which calm inflammation, strengthen the gut lining, and even influence the expression of genes tied to mental health. They also keep the immune system balanced, preventing overreactions that can destabilize mood.
When beneficial bacteria are depleted, butyrate production drops. That leaves the gut lining vulnerable, the immune system reactive, and constant stress signals traveling back to the brain. Research links low short-chain fatty acids directly to higher rates of anxiety and depression. Clinically, we see clients with depleted microbiomes report heightened worry, mood swings, and poor stress tolerance.
When beneficial bacteria disappear, the gut loses one of its strongest stabilizers - and the brain becomes far more vulnerable to anxiety.
The Microbiome–Mood Connection Is Real
GI Infections, Inflammation & Histamine Dysregulation: Hidden Triggers of Anxiety
Gut infections like SIBO, Candida, or parasites don’t just cause digestive distress - they create widespread inflammation that directly affects the brain. Inflammation disrupts the brain’s ability to respond to neurotransmitters like serotonin and dopamine - so even when your body makes them, they don’t have the same calming effect.
At the same time, microbial imbalances often drive histamine overload. Histamine doesn’t just cause congestion or itching - in the brain, it feels like anxiety: racing heart, restlessness, irritability, insomnia, even panic-like symptoms. And when beneficial bacteria are already low, the immune system has no buffer, leaving histamine unchecked.
This is why so many people describe feeling “on edge for no reason.” The reason is real, it’s rooted in inflammation and histamine dysregulation triggered by gut imbalance.
Inflammation & Histamine: Hidden Anxiety Triggers
Detox & Drainage Bottlenecks: When the Gut Environment Turns Against the Brain
Your liver, gallbladder, lymph, and colon don’t just handle detox; they shape the environment inside the gut itself. When these pathways are sluggish, waste products, hormones, and toxins linger in the digestive tract instead of being cleared. This buildup creates a breeding ground for dysbiosis, histamine release, and chronic inflammation, all of which directly affect the brain.
One key example is estrogen clearance. The liver packages estrogen for elimination through bile and the stool. If bile flow or colon clearance is impaired, estrogen is reabsorbed back into circulation. Excess estrogen doesn’t just fuel hormone-related mood swings - it also drives histamine release in the gut, heightening anxiety, irritability, and restlessness.
On top of that, stagnant bile and poor detox allow bacterial byproducts like lipopolysaccharides (LPS) to build up. LPS weakens the gut lining, leaks into circulation, and sparks systemic inflammation that crosses into the brain. This kind of neuroinflammation doesn’t just cause “foggy thinking” - it disrupts neurotransmitter signaling and fuels the restless, agitated state many people describe as anxiety. Add to this the burden of mold toxins (mycotoxins) such as zearalenone or other metabolic waste that should have been cleared, and the nervous system is pushed into a constant state of overdrive.
When detox and drainage slow, the gut becomes congested, the microbiome destabilizes, and toxins recirculate, leaving the brain overwhelmed and mood regulation on edge.
Detox Bottlenecks Can Overwhelm Your Brain
From Gut Repair to Calmer Mood: Why Testing Matters
Our client S came to us with chronic constipation, brain fog, and a persistent undercurrent of anxiety. On her functional stool test, we uncovered several key imbalances: significant bacterial overgrowth, congested drainage with poor bile flow, and clear signs of maldigestion with low digestive enzyme output. Additional testing revealed high levels of mycotoxins, specifically zearalenone, an estrogen-mimicking toxin known to disrupt immune balance, fuel inflammation, and further drive histamine release.
Each of these findings is tied directly to her mental health struggles. Poor enzyme output meant her brain wasn’t getting the nutrients needed for neurotransmitters. Stagnant bile and poor detox allowed toxins and hormones to recirculate, fueling mood swings and restlessness. Zearalenone amplified estrogenic activity and histamine burden, which heightened her anxiety and left her nervous system overstimulated.
At the start, S rated her symptoms as anxiety 5/5, depression 2/5, and mood imbalance 3/5. After just three months of targeted gut repair, detox support, and nutritional repletion, her anxiety dropped to a 3, depression to a 1, and mood imbalance to a 1. She also reported better energy, steady mood and outlook, improved sleep, no more brain fog, and gradual relief from her long-standing constipation.
Her story highlights the most important takeaway: not all of these gut dynamics are at play in every person. That’s why testing is essential. By identifying whether anxiety is being fueled by maldigestion, microbiome depletion, inflammation, detox issues, or a combination, we can design a plan that addresses the real root cause in the right order. When the gut is supported properly, the brain finally has the stability it’s been missing and can heal both the brain and the body together.
👉 This fall, we’re opening spots for 1:1 Functional Nutrition Coaching to radically improve your health, uncover your root causes, and bring lasting relief from symptoms like anxiety, gut issues, and fatigue. If you’re ready to transform your health, book your strategy call here and let’s get started.
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