Autoimmune gastritis occurs when your immune system mistakenly attacks the lining of your stomach. This can lead to inflammation, pain, and problems absorbing nutrients. Understanding this condition helps you work with your healthcare team to manage symptoms and prevent complications.
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What is Autoimmune Gastritis?
Autoimmune gastritis is a condition where your body’s defense system attacks healthy cells in your stomach. This causes inflammation that can damage the stomach lining.
The most common form is autoimmune gastritis, which mainly affects the stomach. When severe, it can lead to pernicious anemia, a condition where your body can’t absorb vitamin B12 properly (1).
Types of Autoimmune Gastritis
There are several types of autoimmune conditions that affect the stomach. Each has unique features and requires different treatment approaches.
Autoimmune Gastritis and Pernicious Anemia
Autoimmune gastritis is the most well-studied form. It happens when your immune system attacks cells in your stomach that make stomach acid and a protein called intrinsic factor. Without intrinsic factor, your body can’t absorb vitamin B12.
Research shows that people with pernicious anemia are actually protected from H. pylori infection. Only 11% of people with pernicious anemia have this bacteria, compared to 71% of healthy people (2).
All patients with pernicious anemia have abnormal stomach tissue. The study found that 75% have atrophic changes in their stomach lining, compared to only 7% in healthy people (2).
Collagenous Gastritis
Collagenous gastritis is a rare condition where collagen (a type of protein) builds up under the stomach lining. Only 30 cases have been reported in medical literature. This condition shows two different patterns based on age (3).
In children and young adults (average age 12), it causes anemia and stomach pain. In older adults (average age 52), it mainly causes loose stools and is often linked to other autoimmune conditions.
An autoimmune cause seems likely because it’s associated with other autoimmune diseases. The condition can last for years or come and go over time (3).
Symptoms of Autoimmune Gastritis
Symptoms vary depending on which type you have and how severe it is. Pernicious anemia has been studied the most, so we know more about its symptoms.
Common Symptoms of Pernicious Anemia
A review of 103 adults with pernicious anemia found these most frequent symptoms (1):
- Fatigue (55% of patients)
- Loss of sensation in arms or legs (32%)
- Excessive weight loss (27%)
- Sore tongue (23%)
These symptoms happen because vitamin B12 deficiency affects many body systems. Your nerves, blood cells, and energy production all need B12 to work properly.
Symptoms of Collagenous Gastritis
Symptoms depend on your age. Young people typically have:
- Anemia (low red blood cells)
- Stomach pain
- Fatigue from blood loss
Older adults more often experience:
- Chronic diarrhea
- Weight loss
- Symptoms of related conditions like celiac disease
Causes and Risk Factors
Autoimmune gastritis happens when your immune system makes a mistake. Instead of fighting germs, it attacks healthy cells in your stomach.
Genetic Factors
These conditions often run in families. If you have relatives with autoimmune diseases, you may be at higher risk.
Related Autoimmune Conditions
People with autoimmune gastritis often have other autoimmune problems. For example, those with gastric cancer (which can develop from chronic gastritis) have higher rates of thyroid antibodies. One study found 25% of gastric cancer patients had antithyroid antibodies, compared to much lower rates in healthy people (4).
Collagenous gastritis is associated with celiac disease and collagenous colitis. This suggests a shared autoimmune process affecting different parts of the digestive system.
Age and Gender
Different types affect different age groups:
- Pernicious anemia is most common in older adults
- Collagenous gastritis can affect any age but shows two peak periods
- Women are more likely to develop most autoimmune conditions
Diagnosis
Diagnosing autoimmune gastritis requires several tests. Your doctor needs to rule out other causes of your symptoms.
Blood Tests
Blood tests can show:
- Low vitamin B12 levels
- Antibodies against stomach cells
- Anemia (low red blood cells)
- Large red blood cells (common in B12 deficiency)
Endoscopy and Biopsy
Your doctor may need to look inside your stomach with a camera (endoscopy). They can take small tissue samples (biopsies) to check for inflammation and damage.
In pernicious anemia, biopsies show inflammation and damage to the stomach lining. Half of patients also have inflammation in the lower part of the stomach (2).
Treatment Options
Treatment depends on the type and severity of your condition. The goal is to reduce inflammation, replace missing nutrients, and prevent complications.
Vitamin B12 Replacement
For pernicious anemia, vitamin B12 replacement is essential. Since you can’t absorb B12 from food, you’ll need:
- Regular B12 injections
- High-dose oral B12 supplements (in some cases)
- Lifelong treatment to prevent deficiency
Managing Inflammation
Doctors may prescribe medications to reduce inflammation. Treatment is often empirical (based on what works) since these are rare conditions (3).
Monitoring for Complications
People with chronic gastritis need regular monitoring. There’s an increased risk of developing certain stomach tumors. A study of gastric carcinoids (a type of tumor) found that 140 out of 347 patients with multiple tumors also had type A gastritis (the autoimmune type) (5).
Diet and Lifestyle Management
While the research doesn’t specify particular foods to avoid, general dietary advice for autoimmune gastritis includes eating foods that are gentle on your stomach.
Foods That May Help
Consider including:
- Foods rich in B vitamins (if you can absorb them)
- Iron-rich foods if you have anemia
- Easy-to-digest proteins
- Cooked vegetables rather than raw
General Dietary Tips
- Eat smaller, more frequent meals
- Avoid very hot or cold foods
- Limit spicy or acidic foods if they cause discomfort
- Stay hydrated, especially if you have diarrhea
Living with Autoimmune Gastritis
Managing an autoimmune condition requires ongoing care and attention. Here’s how to live well with your diagnosis.
Regular Medical Care
You’ll need regular check-ups to:
- Monitor vitamin levels
- Check for anemia
- Watch for complications
- Adjust treatments as needed
Managing Fatigue
Since fatigue affects more than half of people with pernicious anemia, learning to manage your energy is important. Try to:
- Plan activities when you have the most energy
- Take regular breaks
- Get enough sleep
- Ask for help when you need it
Dealing with Neurological Symptoms
If you have numbness or tingling from B12 deficiency, early treatment is crucial. These symptoms can become permanent if left untreated. Physical therapy may help maintain function.
When to See a Doctor
Contact your healthcare provider if you experience:
- Persistent fatigue that doesn’t improve with rest
- Unexplained weight loss
- Numbness or tingling in hands or feet
- Chronic diarrhea
- Severe stomach pain
- Signs of anemia (pale skin, weakness, shortness of breath)
Frequently Asked Questions
Understanding your condition better helps you manage it effectively. Here are answers to common questions.
Can autoimmune gastritis be cured?
Is autoimmune gastritis hereditary?
Can I still absorb nutrients with autoimmune gastritis?
How often do I need B12 injections?
The Bottom Line
Autoimmune gastritis is a condition where your immune system attacks your stomach lining. The most common type can lead to pernicious anemia and vitamin B12 deficiency.
If you suspect you might have autoimmune gastritis, talk to your doctor. With proper diagnosis and treatment, most people can live healthy, active lives despite their condition.