Why does the stomach produce gastric acid?

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Last updated: May 13, 2025View editorial policy

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From the Guidelines

Acid is produced in the stomach to aid in digestion and protect the body from harmful pathogens, with the production of stomach acid being regulated by hormones, neurotransmitters, and the presence of food in the stomach. The stomach contains specialized cells called parietal cells that secrete hydrochloric acid (HCl), creating the highly acidic environment with a pH between 1.5 and 3.5. This acidity serves several crucial functions, including:

  • Breaking down food proteins into smaller peptides
  • Activating digestive enzymes like pepsin
  • Killing harmful bacteria and microorganisms that enter with food
  • Helping absorb nutrients like iron and vitamin B12
  • Signaling other digestive processes

The production of stomach acid is a complex process that involves the interplay of various physiological mechanisms, as noted in a recent study on the de-prescribing of proton pump inhibitors 1. According to this study, the inhibition of gastric acid production by proton pump inhibitors (PPIs) can lead to an increase in intragastric pH, resulting in a rise in serum gastrin levels, which in turn promotes the proliferation of parietal cells and enterochromaffin-like cells. This can increase the capacity of the stomach to produce acid, a phenomenon known as rebound acid hypersecretion (RAHS) 1. The stomach's ability to produce acid is essential for maintaining a healthy digestive system, and any disruption to this balance can lead to various gastrointestinal disorders.

From the Research

Gastric Acid Production

  • Gastric acid production is a unique and central component of the stomach's contribution to the digestive process 2
  • Acid bathes the food bolus while stored in the stomach, facilitating digestion 2
  • The stomach's defense mechanisms against acid injury are essential to avoid ulceration 2

Role of Proton Pump Inhibitors

  • Proton pump inhibitors (PPIs) inhibit the final step of acid secretion, and are currently the most potent acid inhibitors 3
  • PPIs suppress gastric acid secretion by blocking the gastric acid pump, H(+)/K(+)-adenosine triphosphatase (ATPase) 4
  • PPIs are widely utilized for the treatment of gastro-oesophageal reflux disease, as well as other acid-related disorders 4

Physiology of Gastric Acid Secretion

  • Understanding the physiology of gastric acid secretion and the pathophysiology of acid-related diseases has led to the development of numerous ways to decrease acid exposure 3
  • The primary function of the stomach is to prepare food for digestion and absorption by the intestine, with acid production playing a key role in this process 2

Challenges and Future Directions

  • Despite the effectiveness of PPIs, some challenges persist in the therapy of acid-related diseases, including management of patients who respond inadequately to PPI therapy 5
  • New antisecretory drugs, such as acid pump-antagonists and potassium channel acid blocking drugs, are being developed to provide more effective and profound gastric acid secretion inhibition 5, 3

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Gastric acid and digestive physiology.

The Surgical clinics of North America, 2011

Research

Developments in the inhibition of gastric acid secretion.

European journal of clinical investigation, 2005

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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