Gastritis: Root Causes, Diet and Healing | Nutritionist
Stomach pain after meals. Persistent nausea. A burning sensation that antacids relieve only briefly. The sense that something in your upper abdomen is always slightly wrong.
This is the daily reality of gastritis, one of the most common gastrointestinal diagnoses worldwide and one of the most frequently mismanaged. The standard approach offers acid suppression. The question it rarely asks is why the stomach became inflamed in the first place, and what it needs in order to heal.
This article sets out what gastritis is, what drives it physiologically, what the evidence supports for mucosal repair, and how I approach it in consultation.
In this article:
What gastritis is, and why the type determines the treatment
The five root causes, from H. pylori to autoimmunity
Why symptoms do not tell you how damaged the lining is
What acid suppression does and does not do
The nutritional protocol, including the evidence on zinc L-carnosine
The micronutrient deficiencies gastritis creates
When endoscopy is warranted
What is gastritis?
Gastritis is inflammation of the gastric mucosa, the lining of the stomach. It can be acute, with sudden onset and resolution within days, or chronic, persisting for months or years and often without obvious symptoms.
Clinically it is classified by cause and by what the tissue looks like under the microscope. The type decides the treatment, which is why the distinction is not academic.
Type | Cause | Stomach acid | What it leads to |
Acute | NSAIDs, alcohol, severe physiological stress, acute H. pylori | Usually normal | Resolves in days once the trigger is removed |
Type A, autoimmune | Immune attack on parietal cells | Low | B12 deficiency, pernicious anaemia, iron deficiency |
Type B, infectious | H. pylori in the gastric antrum | Variable | The most common form worldwide. Can progress to atrophy |
Type C, chemical | Bile reflux, NSAIDs, alcohol | Usually normal | Erosions and ulceration |
Atrophic | Late H. pylori or autoimmune disease | Low | Intestinal metaplasia, raised gastric cancer risk |
The Sydney System and the Kyoto Global Consensus classify gastritis by topography, morphology and aetiology, on the principle that the underlying cause determines the treatment.
Clinical note: "gastritis" on a report is a description, not a diagnosis. Autoimmune gastritis and H. pylori gastritis produce similar inflammation and require completely different management. Establishing which one you have is the first decision, not an optional refinement.
How common is gastritis?
H. pylori, the organism behind most chronic gastritis, infects roughly 44% of the global population, making it one of the most prevalent bacterial infections in existence. In parts of Asia, Africa and Latin America, prevalence exceeds 70%.
In Portugal and southern Europe, prevalence remains considerably higher than in northern Europe, with estimates of 60 to 70% in older adults.
Despite this, a large proportion of infected people stay asymptomatic for decades. That is precisely why gastritis often goes undetected until the mucosa has already been significantly damaged.
What causes gastritis?
1. Helicobacter pylori
H. pylori is a gram negative bacterium adapted to survive in stomach acid. It produces urease, an enzyme that converts urea into ammonia, neutralising the local pH and allowing it to embed in the gastric mucosa.
Once established, it provokes a persistent inflammatory response involving neutrophils, lymphocytes and pro-inflammatory cytokines, particularly IL-8 and TNF-alpha. Over time this can progress from non-atrophic gastritis to atrophic gastritis, then intestinal metaplasia, and in a subset of people to gastric carcinoma. This sequence is the Correa cascade, and it is the clearest argument for identifying and eradicating H. pylori early. I have written separately on H. pylori symptoms, testing and recovery.
2. NSAIDs and medication
Non-steroidal anti-inflammatory drugs, including ibuprofen, aspirin and naproxen, inhibit cyclooxygenase enzymes and reduce the prostaglandins that maintain mucosal integrity. Without that signalling, mucus production falls, bicarbonate secretion drops and mucosal blood flow is impaired, leaving the lining exposed to acid.
Chronic NSAID use is a leading cause of erosive gastritis and peptic ulcer in Western populations. Proton pump inhibitors are commonly prescribed alongside, but they do not address the underlying mucosal vulnerability, and long term use carries its own cost: depletion of magnesium, B12, iron and zinc, and altered microbiome composition.
3. Chronic stress
The stomach is unusually sensitive to the state of the autonomic nervous system. Under sympathetic dominance, blood flow to the gastric mucosa falls, mucus production declines and gastric emptying slows, which together create the conditions for mucosal breakdown.
Stress induced gastritis is a recognised clinical entity in critically ill patients. Chronic low grade psychological stress compromises the same defences more slowly. The gut-brain axis runs in both directions, which means anxiety, poor sleep and emotional strain have measurable effects on gastric tissue rather than imagined ones.
4. Alcohol and dietary irritants
Ethanol is directly toxic to the gastric epithelium. It disrupts tight junction integrity, increases mucosal permeability and stimulates acid secretion. Regular or heavy intake is a significant driver of erosive and haemorrhagic gastritis.
Dietary irritants worth identifying include very spicy food in people whose mucosal defences are already compromised, large quantities of highly acidic food, and ultra-processed food with high salt content, which has been independently associated with denser H. pylori colonisation.
5. Autoimmunity
In autoimmune gastritis the immune system produces antibodies against parietal cells and intrinsic factor. Parietal cells make both hydrochloric acid and intrinsic factor, the protein required for B12 absorption in the terminal ileum.
As parietal cell mass declines, acid production falls, which impairs protein digestion and mineral absorption, particularly iron and calcium, and eventually produces pernicious anaemia. Autoimmune gastritis travels with other autoimmune conditions, including Hashimoto's thyroiditis and type 1 diabetes.
What are the symptoms of gastritis?
Symptoms vary widely by type and severity, and many people with chronic gastritis, including chronic H. pylori infection, have none at all. When present they typically include:
Epigastric pain or burning, often after eating or when the stomach is empty
Nausea, with or without vomiting
Bloating and early satiety, meaning you feel full quickly
Loss of appetite
Belching
In erosive or haemorrhagic cases, dark or tarry stools, or blood in vomit
What is frequently missed: symptoms do not track mucosal damage. Significant atrophic gastritis can be entirely painless, while mild gastritis can be intensely uncomfortable. How you feel is not a measure of how damaged the lining is, which is why clinical assessment and, where indicated, endoscopy decide the question rather than symptom severity.
Do antacids and PPIs heal gastritis?
Standard management usually involves proton pump inhibitors to reduce acid and allow healing, H2 receptor antagonists to reduce histamine stimulated secretion, antacids for short term relief, and antibiotics where H. pylori eradication is required.
For H. pylori positive gastritis, eradication is the evidence based standard of care and is not negotiable. Rising antibiotic resistance, particularly to clarithromycin, has reduced eradication success in many regions, which is why current consensus guidance recommends tailoring regimens to local resistance patterns.
Beyond H. pylori, the conventional approach is largely symptomatic. Suppressing acid provides relief but does not repair the mucosa, and sustained use brings dysbiosis, reduced absorption of B12, magnesium, iron and zinc, higher risk of C. difficile infection, and possible effects on bone density.
Why this matters: nutritional work does not replace medical treatment where medical treatment is indicated. It addresses what medical treatment leaves unresolved. If you are H. pylori positive, take the eradication therapy. The nutritional protocol runs alongside it and continues after it.
How do you heal the stomach lining?
Step 1. Remove what is damaging the lining
Nothing heals while it is still being injured. In practice this means reducing or stopping NSAIDs where possible, in consultation with whoever prescribed them; reducing alcohol, ideally to zero during the healing phase; identifying and removing the foods that reliably trigger your symptoms, which varies between people; and addressing stress physiology, which is the step most often skipped.
Step 2. Support mucosal repair through diet
The gastric mucosa regenerates well once the inflammatory load drops and nutritional support is adequate.
Anti-inflammatory foods. Polyphenols, omega 3 fatty acids and plant diversity reduce both systemic and local inflammation. Extra virgin olive oil, oily fish, berries, dark leafy greens and turmeric all have relevant evidence
Adequate protein. Mucosal repair requires amino acids, glutamine in particular, which is the primary fuel for gastric epithelial cells. Lean meat, eggs, fish and legumes all contribute
Sulforaphane from broccoli sprouts. Broccoli sprouts are a concentrated source of sulforaphane, which has shown direct anti-H. pylori activity and antioxidant effects on gastric tissue in human trials
Fermented foods, with context. Plain live yoghurt and kefir help in people who tolerate them, but in the acute phase or in low acid states they should be introduced slowly
Meal pattern. Smaller, more frequent meals reduce the duration of gastric distension and acid exposure. Leaving two to three hours between the last meal and lying down reduces overnight acid contact with a compromised lining
Step 3. Zinc L-carnosine
Zinc L-carnosine, also called polaprezinc, is a chelate of zinc and L-carnosine used as a prescription mucosal protective agent in Japan since the 1990s. Its mechanism is distinctive: rather than simply raising zinc status, the chelated molecule adheres to damaged mucosa and releases zinc locally at the site of injury.
The evidence is promising rather than settled:
Direct cytoprotective, antioxidant and anti-inflammatory effects on gastric mucosa have been demonstrated in animal and human work
It suppresses the IL-8 and TNF-alpha response that H. pylori triggers in gastric epithelial cells
A systematic review and meta-analysis of randomised trials found polaprezinc based regimens improved H. pylori eradication rates compared with standard triple therapy
A 2025 case report documented clinical and histological improvement in chronic atrophic gastritis after twelve months of supplementation
Clinical note: a case report is a single patient. It is the weakest form of evidence there is, and I include it because the histology was documented rather than because it proves anything. The meta-analysis is the part of this evidence base that carries weight.
Step 4. Correct the deficiencies gastritis creates
Gastritis, atrophic and H. pylori associated forms in particular, impairs absorption of several nutrients:
Nutrient | Why gastritis depletes it | How it shows |
Vitamin B12 | Reduced intrinsic factor and reduced acid both impair absorption | Fatigue, cognitive change, peripheral neuropathy, often before anyone tests for it |
Iron | Acid converts dietary ferric iron to the absorbable ferrous form | Iron deficiency anaemia with no obvious bleeding source |
Vitamin C | Gastric concentrations fall measurably in H. pylori infection | Weaker mucosal defence and more nitrosamine formation |
Folate | Chronic inflammation and malabsorption | Associated with poorer reversal of atrophy and metaplasia |
Zinc | Needed for acid production, and acid is needed to absorb it | Compounds the low acid state it helps cause |
Step 5. Strain-specific probiotics
The stomach was long assumed too acidic to host a microbial community. It is not, and the gastric microbiome is substantially disrupted by H. pylori, by PPIs and by antibiotics.
Lactobacillus reuteri DSMZ 17648 binds specifically to H. pylori and assists its clearance by peristalsis. A meta-analysis found that adding probiotics to eradication therapy improved eradication rates and reduced antibiotic associated side effects including diarrhoea and nausea. Saccharomyces boulardii is well evidenced for reducing those side effects specifically.
Strain specificity decides the outcome here. A generic probiotic chosen off a shelf is not the same intervention as the strains tested in these trials, and should not be expected to do the same thing.
Step 6. Treat the nervous system as part of the protocol
Because the stomach is directly regulated by the autonomic nervous system, stress physiology belongs inside the protocol rather than beside it. The tools with evidence in gut outcomes are unglamorous: extended exhale breathing to raise vagal tone, a consistent sleep schedule to reduce HPA axis activation, regular moderate activity, and psychological support where anxiety or trauma is part of the picture.
Frequently asked questions
What is the difference between gastritis and GERD?
Gastritis is inflammation of the stomach lining. GERD involves stomach acid rising into the oesophagus, producing heartburn and regurgitation. They can coexist and share symptoms, but they are distinct diagnoses with different mechanisms and different management.
Can gastritis heal on its own?
Acute gastritis often resolves once the trigger is removed, whether that is alcohol, an NSAID or an acute stressor. Chronic gastritis driven by H. pylori or autoimmunity does not resolve spontaneously and requires targeted treatment. Left alone it can progress to atrophy and intestinal metaplasia over years.
Is coffee bad for gastritis?
Coffee stimulates acid secretion and slows gastric emptying. With an inflamed lining, and particularly on an empty stomach, it tends to worsen symptoms. I usually recommend reducing or stopping it during the active healing phase. Once the mucosa has recovered, most people reintroduce it without trouble.
Do I have to avoid all acidic foods?
Usually not. The relationship between dietary acidity and symptoms is highly individual, and the state of the mucosal barrier matters far more than the pH of any given food. A healthy lining handles dietary acid without difficulty. Elimination followed by structured reintroduction is more useful than a permanent exclusion list.
Can stress cause gastritis?
Yes. Chronic stress is a well evidenced trigger and a perpetuating factor. Sympathetic dominance reduces mucosal blood flow and mucus production, which compromises the stomach's own defences. Stress management is part of the treatment rather than an adjunct to it.
What is H. pylori and do I need to treat it?
H. pylori is a bacterium that colonises the gastric mucosa and is the leading cause of chronic gastritis worldwide. If you test positive and have symptoms or mucosal changes, eradication is indicated. Asymptomatic carriage in someone without risk factors is a more nuanced decision and belongs with your physician. After eradication, nutritional support for repair still applies.
Can gastritis cause B12 deficiency?
Yes, particularly in autoimmune gastritis where parietal cell destruction reduces intrinsic factor. In H. pylori associated gastritis, chronic inflammation and reduced acid output also compromise B12 absorption over time. B12 belongs in any complete gastritis assessment.
How long does it take to improve?
Most people notice symptom improvement within four to eight weeks of a complete protocol. Healing at the histological level takes considerably longer, and in atrophic gastritis is measured in months to years rather than weeks. Expecting the first to mean the second has happened is the most common misreading.
Is low stomach acid or high stomach acid the problem?
Both exist and they are frequently confused. Erosive and H. pylori associated gastritis involve acid damaging a compromised lining. Atrophic and autoimmune gastritis involve too little acid, with the consequences falling on digestion and mineral absorption. Treating one as if it were the other is why some people feel worse on acid suppression rather than better.
When to seek medical investigation
⚠️ Gastritis should be medically evaluated, not self-diagnosed. Seek clinical assessment, including consideration of endoscopy, if you have:H. pylori testing, by breath test, stool antigen or biopsy, belongs in any systematic evaluation of chronic gastric symptoms. If positive, eradication therapy is indicated, and nutritional support around that therapy measurably improves outcomes.
Epigastric symptoms persisting beyond a few weeks
Unexplained weight loss
Difficulty swallowing
Dark or tarry stools, or blood in vomit
Anaemia, or significant fatigue with no clear cause
A family history of gastric cancer
How I work with gastritis in practice
In consultation I treat gastritis as a multifactorial condition requiring investigation rather than symptom management. That means establishing the likely type through autoimmune markers, H. pylori status and medication history; assessing B12, iron, folate, zinc and vitamin C; building a dietary protocol around mucosal repair and removal of active irritants; adding targeted supplementation where the clinical picture supports it; bringing nervous system work inside the plan; and coordinating with your gastroenterologist or GP where medical treatment is ongoing.
Sustainable improvement, in chronic and atrophic forms especially, takes time. Four to eight weeks for symptoms. Considerably longer for the lining itself.
Rita Soares is a functional medicine nutritionist based in Lisbon, Portugal, specialising in gut health, longevity and hormonal balance. Member of the Portuguese Order of Nutritionists (No. 2604N) and the Institute for Functional Medicine.
Scientific references
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Hooi JKY, Lai WY, Ng WK, et al. (2017). Global prevalence of Helicobacter pylori infection: systematic review and meta-analysis. Gastroenterology, 153(2), 420-429. 10.1053/j.gastro.2017.04.022
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De Bastiani R, Fassan M, Rugge M, et al. (2025). Improvement in chronic atrophic gastritis after treatment with zinc L-carnosine. American Journal of Case Reports, 26, e950553. 10.12659/AJCR.950553
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