Gastritis and Pancreatitis: When the Cause Isn't Only Diet

When discomfort, pain, or a burning sensation appears in the upper abdomen after eating, the first response is often to look for the “wrong” foods and try to cut out coffee, remove fatty foods, reduce spicy dishes, or switch to a different diet. Sometimes this really can help keep symptoms under control. But a reduction in symptoms after a change in diet does not confirm that food was the cause: an infection, an autoimmune process, or other factors that diet does not directly affect may lie behind the body's reactions. It is therefore important to distinguish between what triggers or worsens symptoms and what causes the condition itself — including when it comes to an individual genetic predisposition.

Causes of Gastritis and Pancreatitis: Why They Aren't Variations of One Condition

Gastritis and pancreatitis have different etiologies. Important causes of gastritis include Helicobacter pylori (H. pylori) infection, drug-induced mucosal injury, and an autoimmune process (Pennelli et al., Pathologica, 2020). The leading causes of pancreatitis are gallstone disease and alcohol use. Other causes and risk factors for both gastritis and pancreatitis include metabolic, structural, drug-related, autoimmune, and genetic factors (Tenner et al., Am J Gastroenterol, 2024).

What Causes Gastritis and What Role Diet Plays

Helicobacter pylori infection is the main cause of chronic gastritis (Pennelli et al., Pathologica, 2020). Other forms of stomach injury are linked, in particular, to long-term use of nonsteroidal anti-inflammatory drugs, which reduce pain, ease inflammation, and lower fever, to alcohol use, and to bile reflux, which is classified separately as reactive (chemical) gastropathy, among others (Pennelli et al., Pathologica, 2020). A large amount of alcohol can also cause acute erosive gastropathy (damage to the inner lining of the stomach with the formation of superficial sores (erosions) without marked inflammation). A separate mechanism is autoimmune gastritis, in which the immune system directs its response against components of the stomach's parietal cells.

Diet is not considered an important cause of most cases of gastritis or gastropathy (NIDDK, Eating, Diet, & Nutrition for Gastritis & Gastropathy, 2019). Symptoms can indeed worsen after certain foods or drinks, but this does not always mean that they are the cause of the mucosal inflammation.

For more on the role of diet, see the article “Why the Same Diet Produces Different Results in Different People: The Role of Genetics and Metabolism”.

Discomfort after eating does not always mean gastritis: the same symptoms — pain or burning in the upper abdomen, early satiety, a feeling of fullness — may indicate functional dyspepsia, when no organic cause, in particular mucosal inflammation, is found on examination (StatPearls, Functional Dyspepsia, 2024).

What Causes Pancreatitis

Two of the most common causes of acute pancreatitis are gallstone disease (40–70% of cases) and alcohol use (25–35% of cases) (Tenner et al., Am J Gastroenterol, 2024). When neither of these two causes is confirmed, the workup usually continues with an assessment of triglyceride levels: a blood concentration above 1,000 mg/dL raises the likelihood that the cause is severe hypertriglyceridemia (Tenner et al., Am J Gastroenterol, 2024).

The broader metabolic context is covered in the article “Metabolism, Digestion, and Genetics: What Affects the Response to Food”.

Medications can also cause acute pancreatitis, although drug-induced cases occur much less often. Structural causes include congenital anomalies of the pancreatic ducts (Fu & Lucas, Gastrointest Endosc Clin N Am, 2022), and autoimmune pancreatitis forms a separate group — inflammation caused by the body's own immune system rather than an external factor (Sharma et al., Front Med, 2024).

Chronic pancreatitis is a progressive fibroinflammatory process that leads to irreversible structural changes in the pancreas and over time can impair its exocrine and endocrine functions. Repeated episodes of acute pancreatitis are one route to its development, but they are not a prerequisite (Fu & Lucas, Gastrointest Endosc Clin N Am, 2022). In early-onset, recurrent, or idiopathic pancreatitis, and when there is a family history, a doctor may refer the patient for clinical genetic testing (Fu, Lucas, Gastrointest Endosc Clin N Am, 2022).

When Symptoms Require Medical Evaluation

Symptoms require medical evaluation if they persist, recur, or are accompanied by unintentional weight loss, repeated vomiting, signs of bleeding, or jaundice.

Such manifestations can have different causes, so cutting out foods on your own does not replace clinical assessment. If gastritis or atrophic changes in the stomach are suspected, endoscopy and biopsy may be needed (Shah et al., Gastroenterology, 2021). If acute pancreatitis is suspected, the diagnosis is made when at least two of three criteria are present: characteristic pain, elevated pancreatic enzymes, and/or characteristic changes on ultrasound (Tenner et al., Am J Gastroenterol, 2024).

Gastritis and Pancreatitis Have a Different Genetic Component

The genetic role in these conditions is not the same. For gastritis, the best-studied genetic context concerns the autoimmune mechanism. For early-onset, recurrent, idiopathic, and hereditary pancreatitis, genetic factors have an established clinical significance, and in these cases clinical genetic testing may be indicated.

Gastritis: Genetics Are Studied for the Autoimmune Form

Autoimmune gastritis is one of the main causes of atrophic gastritis, along with long-standing H. pylori infection (Shah et al., Gastroenterology, 2021). It is a form in which the body's own immune system attacks the stomach cells that produce hydrochloric acid and intrinsic factor (a protein needed to absorb vitamin B12).

GWAS studies of autoimmune manifestations, in particular pernicious anemia — a late manifestation of this condition — have identified associations with the genes PTPN22 (protein tyrosine phosphatase non-receptor type 22), PNPT1 (polyribonucleotide nucleotidyltransferase 1), HLA-DQB1 (major histocompatibility complex, class II, DQ beta 1), and IL2RA (interleukin 2 receptor subunit alpha). Individual molecular studies also point to a role for ATP4A (ATPase H+/K+ transporting subunit alpha), ATP4B (ATPase H+/K+ transporting subunit beta), AIRE (autoimmune regulator), SLC26A7 (solute carrier family 26 member 7), and SLC26A9 (solute carrier family 26 member 9) in the mechanisms of autoimmune gastritis (Iwamuro et al., Curr Issues Mol Biol, 2023). These data do not mean that a genetic component is absent for other forms of gastritis. They show that autoimmune gastritis specifically has the most clearly described genetic context in the cited literature.

Pancreatitis: Genetic Variants Contribute Differently to Disease Risk

For hereditary and idiopathic pancreatitis, variants have been described in the genes PRSS1 (serine protease 1, cationic trypsinogen), SPINK1 (serine peptidase inhibitor Kazal type 1), CTRC (chymotrypsin C), CFTR (cystic fibrosis transmembrane conductance regulator), and CPA1 (carboxypeptidase A1). These genes are linked to different mechanisms: regulation of trypsin activation and degradation, the function of the pancreatic ductal system, or protein-folding defects in acinar cells (Fu & Lucas, Gastrointest Endosc Clin N Am, 2022).

The clinical significance of a particular variant depends on the gene, the variant itself, and its penetrance (the frequency with which a given gene or allele is expressed in the observable features (the phenotype) of organisms that carry that genotype): for some PRSS1 variants the risk is substantially increased, whereas variants in SPINK1, CTRC, and other genes more often act as predisposing factors or risk modifiers rather than an independent cause (Fu & Lucas, Gastrointest Endosc Clin N Am, 2022).

Two Types of Genetic Information: A Rare Variant and Polygenic Risk

Variants in genes linked to hereditary and early-onset pancreatitis can have very different effects — from highly penetrant PRSS1 variants to variants with reduced penetrance or risk modifiers in SPINK1, CTRC, CFTR, and other genes. Clinical genetic testing looks specifically for such rare variants in a targeted way. A polygenic risk score (PRS) works on a different principle: it sums up the small contribution of many common variants.

For more on how it's calculated, see the article “What Is PRS and What the Numbers in Your Report Mean”.

Where Genetic Information Fits Among Other Health Data

A genetic result does not determine the cause of symptoms on its own. It adds information about a background predisposition that exists independently of the body's current state, and it should be considered alongside symptoms, medical history, laboratory data, and examination results — not instead of them.

Apixmed Prism, and the Ultima genetic panel in particular, uses genetic data to assess individual predisposition across a wide range of indicators and does not establish a diagnosis.

For more about the test, see “The Ultima Genetic Panel by Apixmed Prism”.

Gastritis, Pancreatitis, and Genetics: Answers to Common Questions

Can a genetic test determine whether I have gastritis or pancreatitis right now?

No. A genetic test assesses genetic predisposition, not the presence of inflammation. Gastritis and pancreatitis are diagnosed from clinical findings, laboratory tests, and the results of endoscopy or imaging, when such diagnostic methods are indicated.

Does a high genetic risk of gastritis or pancreatitis mean I will necessarily get sick?

No. A polygenic risk score shows where a person's genetic indicator sits relative to a reference population; it does not determine a future diagnosis. Even rare variants with high penetrance do not mean the disease will inevitably develop, although they are a reason for closer clinical monitoring.

Does PRS replace clinical genetic testing when hereditary pancreatitis is suspected?

No. A polygenic risk score and clinical testing for rare variants answer different questions. If there is early-onset pancreatitis, a family history, or the cause of recurrent pancreatitis cannot be established, the question of clinical genetic testing should be decided separately with a doctor.

Genetic test results are not a diagnosis and not a substitute for a consultation with a doctor. The Apixmed Prism report provides genetic context that complements examination results and helps you make decisions together with your doctor.

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