Can chronic gastritis cause malabsorption?

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Last updated: May 19, 2025View editorial policy

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From the Guidelines

Inactive gastritis can potentially cause malabsorption, particularly of vitamin B12, due to reduced production of intrinsic factor, as evidenced by a study published in 2022 1.

Malabsorption Causes and Effects

When gastritis becomes chronic but inactive, the resulting damage to the stomach lining can lead to malabsorption issues. The most common cause of malabsorption in this context is the decreased production of intrinsic factor, which is essential for vitamin B12 absorption. This can cause B12 malabsorption and eventually lead to pernicious anemia if left untreated.

Associated Nutritional Deficiencies

Additionally, inactive gastritis may impair the absorption of other nutrients like iron, calcium, and magnesium due to decreased stomach acid production. Atrophic gastritis, a form of inactive gastritis where the stomach lining has thinned, is particularly associated with malabsorption issues.

Diagnosis and Treatment

If symptoms like fatigue, weakness, or unexplained weight loss are experienced, it's crucial to consult a healthcare provider who may recommend vitamin B12 supplementation (typically 1000 mcg daily orally or monthly injections), along with other supplements based on specific deficiencies. Treatment typically addresses the underlying cause of gastritis while managing nutritional deficiencies that have developed from malabsorption, as suggested by guidelines published in 2020 1.

Key Considerations

  • Inactive gastritis can lead to reduced production of intrinsic factor, causing vitamin B12 malabsorption.
  • Atrophic gastritis is associated with malabsorption issues due to thinned stomach lining.
  • Symptoms like fatigue, weakness, or unexplained weight loss warrant consultation with a healthcare provider.
  • Treatment involves addressing the underlying cause and managing nutritional deficiencies.

From the Research

Inactive Gastritis and Malabsorption

  • Inactive gastritis, also known as atrophic gastritis, can lead to malabsorption of certain nutrients, including vitamin B-12 2.
  • The suppression of gastric acid in atrophic gastritis can impair the absorption of vitamin B-12 from foods, leading to deficiency 2.
  • Proton pump inhibitors (PPIs), which are commonly used to treat gastritis, can also contribute to vitamin B-12 deficiency, particularly with long-term use 3, 4.

Mechanism of Malabsorption

  • The lack of gastric acid in atrophic gastritis and PPI use can make it difficult for the body to absorb vitamin B-12 from food sources 2.
  • Fortified foods, which contain crystalline vitamin B-12, may be beneficial for individuals with atrophic gastritis or PPI use, as they do not require gastric acid for absorption 2.
  • However, regular consumption of fortified foods may not be enough to restore normal vitamin B-12 status in individuals with atrophic gastritis 2.

Related Conditions and Risks

  • Long-term use of PPIs has been associated with various adverse effects, including micronutrient deficiencies, such as vitamin B-12 deficiency, as well as renal disorders, cardiovascular risks, and fractures 3.
  • Atrophic gastritis and PPI use have also been linked to an increased risk of vitamin B-12 deficiency, particularly in older adults 2, 4.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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