Digestive · Gaster
Stomach
It holds acid strong enough to dissolve metal, and rebuilds its own lining every few days to survive it.
- Resting volume
- ~50 mL, expanding to ~1 L
- Acidity
- pH 1.5 to 3.5
- Lining replaced
- Every 3 to 5 days
- Emptying time
- 2 to 4 hours for a mixed meal
What it does
A muscular mixing chamber. It stores a meal, churns it into chyme, begins protein digestion with pepsin, kills most swallowed pathogens with acid, and releases the result into the small intestine at a controlled rate.
The marvel
Gastric acid sits near pH 1.5 to 3.5, comparable to battery acid. The reason your stomach does not digest itself is a bicarbonate-rich mucus layer plus an epithelium that replaces itself every three to five days. You grow a new stomach lining roughly once a week.
How to serve it well
Know that most ulcers are an infection
Helicobacter pylori and NSAIDs cause the majority of peptic ulcers, not stress or spicy food. H. pylori is testable and curable with antibiotics.
Reflux responds to mechanics
Raising the head of the bed, not eating within three hours of lying down, and weight loss where relevant outperform most dietary elimination for reflux.
Do not run acid suppression forever unsupervised
Proton pump inhibitors are effective and appropriate for real indications, but long-term unmonitored use deserves a conversation, not a repeat prescription on autopilot.
Alcohol and tobacco both loosen the valve
Each reduces lower oesophageal sphincter tone, which is the mechanical cause of most reflux.
Book an appointment
- Indigestion that keeps coming back or needs constant medication
- Unintentional weight loss with appetite change
- Persistent nausea
- Reflux that starts new after age 50
Emergency, go now
- Vomiting blood, or material that looks like coffee grounds
- Black tarry stools
- Sudden severe abdominal pain with a rigid abdomen
- Difficulty swallowing that is getting worse
What you may have been told
“Spicy food and stress cause stomach ulcers.”
This was overturned when Marshall and Warren showed H. pylori causes them, work that won a Nobel Prize in 2005. Spicy food may irritate an existing ulcer. It does not create one.
Where this comes from
- National Institute of Diabetes and Digestive and Kidney Diseases · Peptic ulcers and H. pylori
- NHS · Heartburn and acid reflux
- Nobel Assembly · 2005 Prize in Physiology or Medicine
LUMEN is education, not medical advice, and it cannot know anything about you. It does not diagnose. If something here matches what you are experiencing, take it to a clinician who can examine you.