An Overview of Achlorhydria

Achlorhydria is an absence of hydrochloric acid in the gastric juices produced in the stomach. The condition generally doesn't occur on its own but is a secondary result of some other condition or circumstance, such as H. pylori infection or hypothyroidism. Regardless of its cause, achlorhydria can result in a host of gastrointestinal symptoms from pain to constipation to heartburn.

A man sitting up in bed with a painful stomach
Roy Morsch / Getty Images

Hydrochloric acid, which is produced by the parietal cells within the stomach walls, helps maintain the pH levels in the gastric juices so that the enzymes that help break down food into digestible substances can do their job. It also helps maintain the right acidic environment to keep thwart illness and disease.

Symptoms

Given that achlorhydria arises from a variety of causes, symptoms can vary but generally include one or more of the following:

  • Pain in the upper abdomen below the ribs and above the stomach (the epigastric region)
  • Weight loss
  • Heartburn
  • Nausea
  • Abdominal bloating
  • Diarrhea
  • Acid regurgitation
  • A feeling of fullness faster than normal after eating (early satiety)
  • Vomiting
  • Constipation
  • Difficulty swallowing (dysphagia)

Causes

Longtime use of proton pump inhibitors (PPIs) like Prilosec (omeprazole) and Prevacid (lansoprazole) can cause hypochlorhydria, or reduced hydrochloric acid production, and lead to achlorhydria. Your doctor will monitor your medication usage and investigate based on symptoms.

In addition, it's possible for illnesses to inhibit the parietal cells from functioning, leading to low acid production or none at all.

These include:

  • Helicobacter pylori (H. pylori) infection: A bacterial infection of the stomach that can cause gastritis, peptic ulcers, and gastric cancer
  • Hypothyroidism: Low thyroid hormone levels can negatively affect hydrochloric acid production
  • Autoimmune disorders that designate parietal cells in the stomach as enemies and attack them, such as autoimmune atrophic gastritis. This type of gastritis can be a precursor to pernicious anemia, another autoimmune condition that attacks the parietal cells.
  • Gastric bypass procedures where the largest acid-producing parts of the stomach are either removed or bound
  • Radiation therapy involving the stomach
  • Gastric (stomach) cancer

Achlorhydria tends to occur in older adults, so age is considered a risk factor for the condition.

Diagnosis

If any of the possible causes might apply to you, your doctor may run some tests. However, these tests are generally for diagnosing the suspected primary health condition, not achlorhydria itself.

Some tests your doctor may consider include:

  • Intrinsic factor antibody test, a blood panel that measures intrinsic factor antibody levels: Intrinsic factor is a protein produced by the parietal cells, and pernicious anemia can trigger the body to produce antibodies that attack parietal cells and inhibit intrinsic factor production.
  • Gastric biopsy: During an endoscopy, a flexible scope is inserted into the stomach through the mouth (with the patient sedated) to retrieve a stomach tissue sample. Testing can reveal gastritis, H. pylori infection, and stomach cancer. Elevated bacteria levels can indicate low acid levels.
  • H. pylori test: H. pylori bacterial infection can be detected via blood testing, a urea breath test (breathing into a collection bag), stool test, or endoscopy.
  • Stomach acid test: The patient is injected with gastrin, a hormone that stimulates acid production. Then a tube is inserted into the stomach through the nose or mouth to take a sample for testing. Achlorhydria will yield abnormal stomach fluid volume and pH levels.
  • Serum pepsinogen test: Low levels of pepsinogen, a substance secreted in the stomach and converted to the enzyme pepsin by stomach acid, can indicate achlorhydria. This blood test can also be used as an early screening for gastric cancer.
  • Serum gastrin test: High gastrin levels in blood serum may signal achlorhydria.

Complications

Aside from complications (e.g, gastric cancer) that can arise from ignoring symptoms or not treating underlying conditions, the majority of complications from achlorhydria come from nutrient deficiency.

In cases of autoimmune conditions that attack the parietal cells, the abnormal digestive environment can cause absorption issues leading to iron and vitamin B12 deficiencies.

Achlorhydria has also been linked to vitamin D and calcium deficiency, so an unintended complication can be weak bones, which can result in fractures, especially of the hip.

Treatment

The cause of your achlorhydria will determine your treatment path. For instance, if chronic use of PPIs caused you to develop this condition, the first step your doctor may take is stopping these medications.

If another health condition is causing your achlorhydria, treating that condition will generally alleviate low stomach acid problems. Therefore, individual treatments for pernicious anemia, H. pylori infection, or even gastric cancer will be the default treatment for achlorhydria.

Nutritional supplements like B12, iron, calcium, and vitamin D may also be warranted.

A Word From Verywell

As with most conditions, the earlier achlorhydria is detected, the better your long-term prognosis will be—particularly in the case of gastric cancer and its precursors like H. pylori infection. Even if your symptoms are mild, if they are persistent, be sure to see your doctor.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Fatima R, Aziz M. Achlorhydria. [Updated 2019 Jun 12]. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2020 Jan-.

  2. National Institutes of Health. Genetic and Rare Diseases Information Center. Autoimmune atrophic gastritis. Updated October, 20, 2015.

  3. American Association of Clinical Chemistry. Lab tests online. Intrinsic factor antibody. Updated November 15, 2019

  4. National Institutes of Health. Medline Plus. Gastric tissue biopsy and culture. Updated October 18, 2017.

  5. National Institutes of Health. Medline Plus. Heliobacteria pylori (h.pylori) tests. Updated February 25, 2020.

  6. National Institutes of Health. Medline Plus. Stomach acid test. Updated October 27, 2018.

  7. Liu L, Lang J, Jin Y, et al. The Value of Pepsinogen in GC Screening: A Systematic Review and Meta-Analysis. Gastroenterol Res Pract. 2019;2019:7087232. doi:10.1155/2019/7087232

  8. Cavalcoli F, Zilli A, Conte D, Massironi S. Micronutrient deficiencies in patients with chronic atrophic autoimmune gastritis: A reviewWorld J Gastroenterol. 2017;23(4):563–572. doi:10.3748/wjg.v23.i4.563

Additional Reading