Stomach Acid: What You Need to Know About Hypochlorhydria
Stomach acid, scientifically known as hydrochloric acid (HCl), plays an essential role in our digestive system, helping us to break down foods and providing protection from potentially dangerous bacteria. However, when stomach acid production is too low, a condition known as hypochlorhydria may develop, leading to uncomfortable digestive symptoms and potential health implications, although this is rare. In this article, we will explore the causes of low stomach acid, symptoms of low stomach acid and discuss other more common conditions with similar effects.
What is stomach acid?
Stomach acid is a digestive fluid produced by the stomach that helps break down food into smaller particles. It is composed primarily of hydrochloric acid, pepsin (an enzyme that breaks down proteins), and mucus. The acidic environment created by stomach acid also helps to kill harmful microbes, spores, and parasites that may be present in our food, reducing the risk of gastrointestinal infections (1).
Achlorhydria is the complete loss of stomach acid production while Zollinger-ellison syndrome is when the stomach to produce too much acid.
What is the pH of stomach acid?
The strength of stomach acid is measured using the pH scale, which measures the acidity of liquids. This scale ranges from 1 (most acidic) to 14 (least acidic, or alkaline). Stomach acid should have a pH of between 1.5 and 2 (2). Reduced stomach acid secretions lead to an increased pH (i.e., the stomach becomes less acidic and more alkaline). When the pH of stomach acid exceeds 4 it is considered to be too high and is referred to medically as hypochlorhydria. If the stomach is unable to produce any acid, it is called achlorhydria. This phenomenon is relatively uncommon, with an incidence rate of 2-5% (3).
Symptoms of low stomach acid
The symptoms of hypochlorhydria can include heartburn, bloating, flatulence, gut inflammation, and chronic indigestion. Because these signs overlap significantly with other upper gastrointestinal conditions, experiencing them regularly means it is vital to consult a healthcare provider to determine the precise underlying cause.
Interestingly, the vast majority of heartburn and indigestion cases are not caused by low stomach acid, but rather by Gastro-Esophageal Reflux Disease (GERD)—which occurs when stomach contents flow back up into the esophagus. While it is occasionally claimed in wellness spaces that GERD itself is caused by insufficient stomach acid, there is very limited clinical evidence supporting this.
The conventional treatment plan for severe GERD typically includes Proton Pump Inhibitors (PPIs, such as omeprazole) and antacids. PPIs effectively block gastric acid release to offer rapid symptom relief. However, long-term, chronic use of these medications can inadvertently cause low stomach acid. While PPIs are one of the most frequently prescribed classes of drugs worldwide, clinical studies consistently report that they are widely overprescribed.
Over time, chronically low stomach acid can lead to severe nutrient deficiencies. Many vital digestive enzymes, such as pepsin, require a highly acidic environment to activate; they become sluggish and inefficient in a higher pH environment. Furthermore, a pH increase in the stomach renders the gastric barrier less lethal to ingested microbes. This compromised defense mechanism significantly increases the risk of intestinal infections and Small Intestinal Bacterial Overgrowth (SIBO) or Intestinal Methanogen Overgrowth (IMO).
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What causes low stomach acid?
Low stomach acid is relatively uncommon, and there has been little research on its underlying cause. Causes of low stomach acid may be age, autoimmune disorders damaging the stomach lining or thyroid, or the use of (PPIs), antacids and acid blockers (5). Helicobacter pylori infection is also a known cause of hypochlorhydria, due to the bacteria’s interference with the stomach’s acid-producing cells.
Low stomach acid tests
If it is thought that you are showing signs of low stomach acid, you may need a low stomach acid test. A gastric acid output test is often used. This is conducted with a capsule or probe and a pH sensor that is placed into the stomach. A standardised meal is given, such as a nutrient drink, that will buffer the acid levels in the stomach. The time it takes for your stomach to reacidify after the meal is then recorded.
Managing Stomach Acid Levels Effectively
When low stomach acid is formally identified, independent practitioners often focus on supporting the gastric environment. This may involve the temporary, targeted use of hydrochloric acid (betaine HCl) supplements to lower the pH of the stomach during meals, alongside concentrated digestive enzymes to ensure food is broken down completely. While popular home remedies like apple cider vinegar share a similar acidic pH (around 2.5) and are frequently claimed to aid digestion, more rigorous clinical research is required to validate their therapeutic efficacy.
From a dietary perspective, managing hypochlorhydria involves prioritizing easily digestible, whole foods. In some instances, incorporating natural prokinetics and digestive stimulants like ginger can help support overall gastric motility and secretions.
Ultimately, while low stomach acid is a distinct clinical condition, it remains relatively rare and is not the origin of most everyday digestive complaints. If you are navigating persistent heartburn, shifting motility, or unmanageable bloating, working directly with an independent clinician is the safest path forward.
By integrating the OMED Health Breath Analyzer and App into your care, you can provide your independent specialist with a continuous, longitudinal stream of hydrogen and methane data. This objective tracking eliminates trial-and-error, allowing your practitioner to see exactly how your upper digestive system responds to lifestyle and dietary adjustments, and helping them build a targeted, data-driven plan to restore long-term equilibrium.
References
- Hunt RH, Camilleri M, Crowe SE, et al. The stomach in health and disease. Gut. 2015;64(10):1650. doi:10.1136/GUTJNL-2014-307595
- Fujimori S. Gastric acid level of humans must decrease in the future. World J Gastroenterol. 2020;26(43):6706-6709. doi:10.3748/wjg.v26.i43.6706
- Fatima R, Aziz M. Achlorhydria. South Med J. 2023;21(11):920-924. doi:10.1097/00007611-192811000-00010
- Wang KK, Genere JR. Gastroesophageal Reflux Disease (GERD). Mo Med. 2018;115(3):214. doi:10.1016/B978-0-12-801238-3.65937-8
- Freedberg DE, Lebwohl B, Abrams JA. The impact of proton pump inhibitors on the human gastrointestinal microbiome. Clin Lab Med. 2014;34(4):771. doi:10.1016/J.CLL.2014.08.008
- Forgacs I, Loganayagam A. Overprescribing proton pump inhibitors. BMJ : British Medical Journal. 2008;336(7634):2. doi:10.1136/BMJ.39406.449456.BE
