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Can low stomach acid cause anxiety?

Anxiety is a common condition that affects millions of people worldwide. It is characterized by feelings of worry, nervousness, and fear. While the exact causes of anxiety are complex, some research indicates a potential link between low stomach acid levels (hypochlorhydria) and anxiety.

What is hypochlorhydria?

Hypochlorhydria refers to insufficient levels of hydrochloric acid (HCl) in the stomach. HCl is produced by parietal cells in the stomach and plays an important role in protein digestion and absorption of vitamins and minerals. It also destroys potentially harmful microbes that are ingested.

Some common signs and symptoms of hypochlorhydria include:

  • Bloating or fullness after meals
  • Indigestion
  • Diarrhea or constipation
  • Nausea after taking supplements
  • Nutritional deficiencies
  • Weak, peeling, or cracked fingernails

Hypochlorhydria can be caused by aging, autoimmune conditions, long-term stress, infections like Helicobacter pylori, or long-term use of antacids. Stomach surgery or radiation can also damage parietal cells and reduce HCl production.

How might low stomach acid contribute to anxiety?

While more research is needed, some theories suggest hypochlorhydria may contribute to anxiety in the following ways:

Nutrient deficiencies

Stomach acid helps break down proteins and release micronutrients like zinc, iron, vitamin B12, and folate from food. Low HCl can impair this process and lead to deficiencies over time.

Folate, vitamin B12, iron, and zinc all play important roles in mood regulation and brain function. Deficiencies in these nutrients have been associated with increased anxiety in some studies.

Dysbiosis and inflammation

With inadequate stomach acid, partially digested food can make its way to the intestines and feed harmful bacteria and yeast. This imbalance between good and bad microbes is called dysbiosis and has been linked to inflammation throughout the body and brain.

Some research indicates this GI inflammation can alter signaling between the gut and brain, which may contribute to anxiety symptoms in some individuals.

Impaired digestion and absorption

Protein is critical for the production of neurotransmitters like serotonin and dopamine that regulate mood and emotions. Without enough HCl, protein digestion is impaired. This may result in neurotransmitter imbalances that affect anxiety levels.

Hypochlorhydria can also reduce absorption of amino acids needed as precursors for neurotransmitter production.

Nutritional deficiencies and leaky gut

Mechanism Impact on Anxiety
Insufficient stomach acid leads to impaired digestion and absorption of protein, iron, vitamin B12, folate and other nutrients. Deficiencies in these nutrients can reduce production of serotonin, dopamine, and other neurotransmitters that regulate mood and emotions.
Low stomach acid allows partially digested food particles to enter the intestines, feeding pathogenic bacteria and yeast (dysbiosis). Dysbiosis and inflammation in the gut may alter gut-brain communication pathways and contribute to anxiety symptoms.
Dysbiosis also damages the intestinal lining over time, allowing incompletely digested proteins to enter the bloodstream (leaky gut). These proteins may interact with the nervous system and trigger anxiety responses.

Other causes of anxiety

While low stomach acid might play a role, it is important to note that anxiety is a complex condition with many contributing factors, including:

  • Genetics and family history
  • Brain chemistry and neurotransmitter imbalances
  • Environmental stressors
  • Traumatic life events
  • Medical conditions like thyroid disorders
  • Use of certain medications or drugs
  • High levels of inflammation

For some individuals, anxiety may be caused more by one of these other factors rather than low stomach acid alone. Anxiety should be evaluated by a medical professional to identify any underlying causes or contributors.

Testing for hypochlorhydria

If hypochlorhydria is suspected, some ways to test stomach acid levels include:

Heidelberg capsule test

This is considered the gold standard test. It involves swallowing a small capsule attached to a thin tube. It directly measures pH levels at various points as it travels through your gastrointestinal tract.

Gastric function panel

This is a blood test that measures levels of the digestive enzyme pepsinogen. Low levels can indicate impaired stomach acid production.

Baking soda stomach acid test

This simple at-home test involves drinking a mixture of baking soda and water on an empty stomach. Your belching response provides clues about stomach acidity.

Betaine HCl challenge

For this test, you take a supplement containing betaine HCl with a protein-containing meal. If it makes you feel better, it indicates your stomach likely needs more acid.

Keep in mind that these tests can sometimes yield inaccurate results. It’s best to work with a doctor knowledgeable about stomach acid issues when exploring hypochlorhydria as a potential cause.

Treatment for low stomach acid

If low stomach acid is identified as an issue contributing to anxiety, some treatment approaches may include:

Dietary changes

Eating smaller, more frequent meals loaded with fruits and vegetables may help reduce symptoms. Limiting sweets, refined carbs, and processed foods can help minimize dysbiosis.


Betaine HCl supplements are commonly used to increase stomach acid temporarily with meals. Bitter herbs like gentian may also stimulate acid production.Nutrient supplements can help correct any deficiencies that may be contributing to anxiety.

Stress management

Chronic stress negatively impacts HCl production. Relaxation techniques like meditation, yoga, deep breathing can minimize its effects.

Probiotics and prebiotics

These supplements help populate the gut beneficial bacteria to reduce dysbiosis. They may also improve gut barrier function.


Drugs that reduce stomach acid production may be discontinued if appropriate. Prescription strength HCl supplements or pro-motility drugs may be options in some cases.

Keep in mind that low stomach acid alone is unlikely to be the sole cause of anxiety for most people. A comprehensive treatment plan should address any other potential contributors as well.


In summary, while more research is still needed, some evidence suggests low stomach acid could potentially contribute to anxiety in certain individuals. Theories include impaired digestion and absorption of nutrients important for neurotransmitters, dysbiosis and inflammation, and leaky gut. If hypochlorhydria is identified through medical testing, approaches like dietary changes, supplements, and stress reduction may help reduce anxiety levels. However, anxiety is a complex disorder with many possible causes, so other potential factors should be evaluated as well.