Heartburn: Too Much Acid or Too Little? The Surprising Truth
Heartburn, that burning sensation that rises from the stomach to the chest and throat, is an extremely common ailment. The instinctive reaction of those who suffer from it, and often popular advice, is to assume it's due to excess stomach acid . Millions of people turn to antacids to neutralize it. However, a growing body of evidence and clinical experience suggest a paradoxical reality: in many cases, heartburn and acid reflux could, in fact, be symptoms of insufficient hydrochloric acid (HCl) production in the stomach.
This article explores this counterintuitive perspective, explaining how a lack of acid can cause symptoms we mistakenly attribute to an excess of it, and why understanding this difference is crucial to addressing the root of the problem.
The Common Paradigm vs. The Hypochlorhydria Hypothesis
Conventional wisdom dictates that acid reflux occurs when stomach contents, rich in acid, escape into the esophagus, a tube ill-equipped to withstand such acidity, causing irritation and the characteristic burning sensation. The logical solution, then, seems to be to reduce or neutralize that acid.
However, hypochlorhydria (low stomach acid production) or even achlorhydria (total absence of acid) may be the underlying cause in a significant number of people with chronic reflux, especially as we age. How is this possible?
How Can a Lack of Acid Cause Reflux? The Key Mechanisms
The connection between low acid and reflux is explained through several interrelated mechanisms:
1. Lower Esophageal Sphincter (LES) Malfunction
The LES (lower esophageal sphincter) is a muscular valve located between the esophagus and the stomach. Its function is to open to allow food to pass through and close tightly to prevent gastric contents from refluxing. Contrary to what one might think, the strongest signal for the LES to close properly is a sufficiently acidic environment in the stomach . When stomach acid is low (higher pH), the LES may not receive the appropriate signal to close completely, remaining relaxed or opening inappropriately, thus allowing even less acidic stomach contents to reflux and irritate the esophagus.
2. Delayed Gastric Emptying
Hydrochloric acid is essential for breaking down proteins and signaling the stomach to release its contents into the small intestine. With low levels of HCl, digestion slows down and food remains in the stomach longer . This delay increases intra-stomach pressure, which can force the LES open and cause reflux.
3. Fermentation and Bacterial Overgrowth
An insufficiently acidic stomach environment fails to adequately sterilize ingested food. This can allow bacteria and yeast to survive and proliferate in the stomach and, more commonly, in the small intestine (known as SIBO – Small Intestinal Bacterial Overgrowth). These bacteria ferment undigested carbohydrates, producing gases (such as hydrogen and methane) . The accumulated gas increases pressure within the abdomen, pushing stomach contents upward and through a potentially weakened lower intestinal tract (LES).
In summary: A low acid level can lead to poor closure of the esophageal valve, slow digestion that increases stomach pressure, and bacterial fermentation that generates gas, all contributing to reflux.
The Vital Importance of Stomach Acid
It is crucial to remember that hydrochloric acid is not an enemy. It is an essential physiological secretion with critical functions:
- Protein Digestion: Activates pepsin, the enzyme that starts the breakdown of proteins.
- Nutrient Absorption: Facilitates the absorption of important minerals such as iron, calcium, magnesium, zinc and vitamin B12.
- Immune Defense: Kills bacteria, viruses, parasites and fungi ingested with food and water, preventing gastrointestinal infections.
- Digestive Stimulation: Signals the release of bile and pancreatic enzymes necessary for digestion in the small intestine.
Low acid production compromises all of these functions.
Beyond Acidity: Other Symptoms of Low Acid Production
If the underlying cause is hypochlorhydria, the person is likely to experience other symptoms besides reflux, such as:
- Bloating, gas, or burping shortly after eating.
- Feeling of heaviness or excessive fullness after meals.
- Frequent indigestion.
- Presence of undigested food in the stool.
- Nutritional deficiencies (anemia due to lack of iron or B12, bone problems due to poor absorption of calcium/magnesium).
- Brittle nails, hair loss.
- Multiple food allergies or intolerances.
- Increased susceptibility to intestinal infections or SIBO.
- Autoimmune diseases (sometimes associated).
What Causes Low Stomach Acid Production?
Several factors can contribute to hypochlorhydria:
- Aging: HCl production tends to decrease with age.
- Chronic Stress: The sympathetic nervous system (fight or flight response) inhibits digestive functions, including acid secretion.
- Helicobacter pylori infection: Although it may initially cause ulcers due to excess acid, chronic infection can lead to gastric atrophy and reduced acid production.
- Prolonged use of antacids and Proton Pump Inhibitors (PPIs): Medications designed to reduce acid can, paradoxically, perpetuate or worsen an underlying low acid problem if that was the initial case, or create iatrogenic hypochlorhydria.
- Nutritional deficiencies: Especially of zinc and B complex vitamins, necessary for the production of HCl.
- Gastric surgery.
- Autoimmune conditions: Such as autoimmune atrophic gastritis or pernicious anemia.
- Hypothyroidism.
The Antacid Trap
Antacid medications (neutralizers, H2 blockers, PPIs) provide temporary symptomatic relief by reducing or neutralizing the acid present in the stomach and the acid that refluxes into the esophagus. This works regardless of whether the root cause is an excess or a deficiency of acid. However, if the problem is hypochlorhydria, continued use of these medications:
- It does not address the real cause (LES malfunction, slow emptying, fermentation).
- It worsens digestion and nutrient absorption in the long term.
- It increases the risk of SIBO and infections.
- It can create dependency and make it difficult to stop treatment.
Assessment and Therapeutic Approach
Warning! Diagnosing hypochlorhydria requires professional evaluation. Do not attempt to self-diagnose or self-medicate with acid supplements (such as betaine HCl) without medical supervision , as this could be dangerous if you have gastritis, ulcers, or if you actually produce excess acid. "Home tests" like the sodium bicarbonate test are highly unreliable.
A healthcare professional (doctor, gastroenterologist, functional nutritionist) can evaluate your symptoms, medical history, and, if necessary, order specific tests such as:
- Blood tests to detect deficiencies (iron, B12, etc.) or antibodies (celiac disease, gastric autoimmunity).
- Breath test for SIBO or H. pylori.
- Endoscopy to visualize the esophagus and stomach.
- More specialized tests such as the Heidelberg capsule (which measures gastric pH directly) or complete stool analysis.
If hypochlorhydria is confirmed, treatment focuses on:
- Identify and treat the underlying cause (stress, H. pylori, etc.).
- Optimize digestive habits: Eat calmly, chew food very well, avoid drinking large amounts of liquid with meals.
- Dietary support: Include bitter foods (arugula, endive) that stimulate digestion, consider diluted apple cider vinegar before meals (with caution and individual tolerance).
- Stress management: Relaxation techniques, meditation, gentle exercise.
- Supervised supplementation: In some cases, and always under professional supervision, the temporary use of digestive enzymes or betaine HCl supplements may be considered to support digestion while restoring natural acid production.
Conclusion: Reconsidering the Cause of Your Heartburn
The idea that heartburn can be caused by a lack of stomach acid is certainly surprising to many. However, understanding the physiological mechanisms behind reflux and the vital functions of hydrochloric acid opens new perspectives for addressing this common ailment.
If you suffer from chronic heartburn, especially if you experience other digestive symptoms or if antacids only offer temporary relief without resolving the underlying problem, consider the possibility that hypochlorhydria (low body water) is a contributing factor. The most important step is to seek a professional evaluation for an accurate diagnosis and an appropriate treatment plan that addresses the root cause of the problem, rather than simply masking the symptoms.