What other nutrients should be checked in patients with atrophic gastritis?

Nutrient Screening in Atrophic Gastritis

All patients with atrophic gastritis must be screened for iron and vitamin B-12 deficiencies, regardless of etiology, with particular emphasis on corpus-predominant disease. 1, 2, 3

Primary Nutrients to Check

Iron

• Iron deficiency occurs in up to 50% of patients with corpus-predominant atrophic gastritis and manifests much earlier in the disease course than vitamin B-12 deficiency. 2
• The mechanism involves reduced gastric acid secretion, which impairs iron absorption from dietary sources. 2
• Iron stores deplete rapidly compared to vitamin B-12, making early detection critical. 2
• In autoimmune gastritis specifically, iron deficiency is present in 28.9-33.3% of patients. 4

Vitamin B-12

• Vitamin B-12 deficiency develops due to both reduced gastric acid secretion and loss of intrinsic factor production from parietal cell destruction. 2
• The body has substantial hepatic stores of vitamin B-12 that can last years, so deficiency presents later than iron deficiency. 2
• In autoimmune gastritis, vitamin B-12 deficiency occurs in approximately 13.3% of patients. 4
• Pernicious anemia represents a late-stage manifestation of autoimmune gastritis characterized by vitamin B-12 deficiency and macrocytic anemia. 1

Additional Nutrients to Screen

Vitamin D (25-OH Vitamin D)

• Vitamin D deficiency is the most common micronutrient deficiency in chronic atrophic autoimmune gastritis patients, present in approximately 62% of cases. 5
• Vitamin D levels directly correlate with B-12 levels, suggesting shared pathogenic mechanisms. 5
• This deficiency may be clinically significant but is relatively easy to correct. 6

Folic Acid

• Folic acid deficiency occurs in chronic atrophic autoimmune gastritis, though less frequently than other micronutrients. 6, 5
• Critical pitfall: Doses of folic acid greater than 0.1 mg per day may produce hematologic remission in patients with vitamin B-12 deficiency while allowing irreversible neurologic damage to progress. 7
• Patients must be warned about the danger of taking folic acid in place of vitamin B-12. 7

Calcium

• Calcium deficiency has been increasingly described in patients with chronic atrophic autoimmune gastritis. 6
• Calcium ions are required for gastrointestinal absorption of vitamin B-12 in the terminal ileum. 7

Clinical Approach to Screening

Initial Laboratory Assessment

• Obtain hematocrit, reticulocyte count, vitamin B-12, folate, and iron levels prior to treatment. 7
• Measure ferritin concentration (adjusted for CRP if inflammation is present). 4
• Check 25-OH vitamin D levels in all patients with autoimmune gastritis. 5
• During initial treatment of pernicious anemia, monitor serum potassium closely in the first 48 hours. 7

Follow-Up Monitoring

• Repeat hematocrit and reticulocyte counts daily from the fifth to seventh days of therapy, then frequently until hematocrit normalizes. 7
• If reticulocytes have not increased after treatment or do not continue at least twice normal while hematocrit remains below 35%, reevaluate diagnosis or treatment. 7
• Repeat determinations of iron and folic acid may reveal complicating illness inhibiting marrow response. 7

Important Clinical Considerations

Risk Stratification

• Patients with autoimmune gastritis have a significantly higher risk of developing vitamin B-12 deficiency (OR: 11.52) and iron deficiency (OR: 2.92) compared to control patients. 4
• Age, sex, and H. pylori status do not significantly affect the occurrence of vitamin B-12 or iron deficiency. 4

Reverse Screening

• In patients presenting with unexplained iron or vitamin B-12 deficiency, atrophic gastritis should be considered in the differential diagnosis and appropriate diagnostic evaluation pursued. 1, 2, 3

Associated Autoimmune Conditions

• Screen for autoimmune thyroid disease in all patients with autoimmune gastritis, as up to one-third of patients with autoimmune thyroid disease have autoimmune gastritis. 1, 3

Critical Pitfalls to Avoid

• Never allow vitamin B-12 deficiency to progress for longer than 3 months, as this may produce permanent degenerative lesions of the spinal cord. 7
• Multiple vitamin deficiencies may lead to severe hematological, neurological, and skeletal manifestations. 6
• Nutritional deficiencies in atrophic gastritis are largely understudied and often underdiagnosed. 6
• Hemolytic anemia can rarely occur as a manifestation of severe vitamin B-12 deficiency, mimicking thrombotic microangiopathy. 8