Health Reference LibraryWhat causes indigestion, and what helps?
This entry is part of the Nutri Tailor Health Reference Library — cited research on supplements, nutrients and adjacent areas of health.
Summary
Indigestion is upper abdominal discomfort, fullness, bloating or nausea after eating. The common causes are reflux, Helicobacter pylori infection, anti-inflammatory painkillers, large or late meals, alcohol, coffee, fatty food, smoking and stress. NICE advises smaller meals eaten slowly, the main meal well before bed, weight loss where overweight, stopping smoking, avoiding the triggers a person notices, and cutting anti-inflammatory painkillers where possible. A pharmacist is the first call for antacids and alginates, and a GP offers a Helicobacter test and a short acid suppression course where symptoms persist. Difficulty swallowing, or being 55 or over with weight loss, vomiting, black stools or new persistent symptoms, needs a GP urgently.
How it works
The upper gut has to hold, grind and empty a meal in sequence, and indigestion is what it feels like when any step is off. Large, fatty or late meals sit longer and stretch the stomach; alcohol, coffee and smoking irritate the lining and loosen the valve above it; anti-inflammatory painkillers strip the lining's mucus defence; Helicobacter pylori lives in the lining and inflames it, sometimes to an ulcer; stress slows emptying and sharpens the gut's sensitivity so normal stretch feels like pain. Functional dyspepsia, where tests are normal, is mostly that last mechanism, an oversensitive stomach, which is why eating pattern and stress levers work on it and why supplements that change acid or enzymes mostly do not.
Timing
Meal pattern changes show within days. A Helicobacter test result comes in days and eradication takes a week of prescribed tablets with re-testing after. Acid suppression courses run four weeks for dyspepsia. Functional dyspepsia improves over weeks to months with pattern change and stress work rather than in days.
Safety profile
Difficulty swallowing, unexplained weight loss, persistent vomiting, vomiting blood, black tarry stools, a lump in the abdomen, or new persistent indigestion at 55 or over needs a GP within days and usually a two-week endoscopy referral. Severe upper abdominal pain radiating to the back, or pain with fever and jaundice, is urgent. Chest pain with sweating or breathlessness is a heart attack until proven otherwise, and the response is a 999 call. Iron deficiency anaemia alongside indigestion needs investigation. Regular anti-inflammatory painkillers with indigestion are a GP conversation because of ulcer risk.
Special populations
Pregnancy indigestion is common and managed with meal pattern and pharmacist-advised antacids. Older adults on aspirin or anti-inflammatory painkillers are at highest ulcer risk. People with diabetes can have slowed stomach emptying driving fullness and nausea. Anyone with a family history of stomach cancer has a lower threshold for endoscopy.
Guideline positions
NICE CG184: offer simple lifestyle advice including healthy eating, weight reduction and smoking cessation; advise avoiding known precipitants including smoking, alcohol, coffee, chocolate, fatty foods and being overweight; raising the head of the bed and a main meal well before bed may help some people; community pharmacists offer initial advice, over-the-counter options and guidance on when to see a GP; offer Helicobacter pylori test-and-eradicate for dyspepsia, leaving two weeks after acid suppression before testing; offer a full-dose acid suppression course for four weeks for dyspepsia; review anti-inflammatory painkiller use. Urgent endoscopy within two weeks for dysphagia, or age 55 and over with weight loss. The NICE quality standard specifies the main meal at least three hours before bed.
Practical framework
The pattern comes first, because indigestion usually has one, through two weeks of a simple food-and-symptom note covering what, when, how much, and what followed. The levers then run as follows. Meals become smaller and slower, with the main meal at lunchtime or early evening and nothing in the three hours before bed. Coffee and alcohol are reduced or moved earlier. Fatty and very spicy food are trialled out and back in to see what matters. Anti-inflammatory painkillers are swapped for paracetamol where a pharmacist agrees. Smoking stops, and weight comes down where the waist is over 94 cm in men or 80 cm in women. Stress is a real driver and the levers on [how to lower cortisol](/apps/learn/how-to-lower-cortisol-what-the-evidence-supports) apply. A pharmacist covers antacids or alginates for episodes. Where a fortnight of this has not settled it, a GP provides a Helicobacter test and a short acid suppression course. Where bloating is the main complaint, [how to stop bloating](/apps/learn/how-to-stop-bloating-causes-and-what-actually-works) is the better page. Nutri365 reads whether symptoms track meal size, timing, alcohol, painkillers or stress across those weeks, checks for interactions and contraindications against anything prescribed, and refers questions outside scope to a health specialist.
Common misconceptions
Indigestion is not usually low stomach acid, and acid-increasing supplements do not have guideline evidence for dyspepsia. Digestive enzyme capsules help specific deficiencies, not ordinary indigestion, as set out on the [digestive enzymes page](/apps/learn/digestive-enzymes-what-they-do-and-what-the-evidence-shows). Peppermint helps some IBS-type symptoms but worsens reflux. And fullness after moderate meals that persists for weeks is a GP symptom, not a diet problem.
Sources
- 2019. Gastro-oesophageal reflux disease and dyspepsia in adults: investigation and management (CG184). NICE.
- 2015. Dyspepsia and gastro-oesophageal reflux disease in adults, quality statement 1. NICE.