Nutritional Deficiencies in Atrophic Gastritis
Patients with atrophic gastritis, particularly corpus-predominant disease, develop iron and vitamin B-12 deficiency as the primary nutritional deficiencies, with iron deficiency typically manifesting earlier than B-12 deficiency. 1
Primary Micronutrient Deficiencies
Iron Deficiency
- Iron deficiency occurs in up to 50% of patients with corpus-predominant atrophic gastritis and presents much earlier in the disease course than vitamin B-12 deficiency 1
- The mechanism is reduced gastric acid secretion, which impairs iron absorption from dietary sources 1
- In autoimmune gastritis specifically, iron deficiency occurs in approximately 29-33% of patients, significantly higher than control populations 2
Vitamin B-12 Deficiency
- Vitamin B-12 deficiency develops due to both reduced gastric acid secretion and loss of intrinsic factor production from parietal cell destruction 1
- Approximately 13% of autoimmune gastritis patients develop frank vitamin B-12 deficiency, compared to only 1.5% in H. pylori-related gastritis 2
- Autoimmune gastritis patients have an 11.5-fold increased risk of vitamin B-12 deficiency compared to controls 2
- This deficiency leads to megaloblastic anemia and can cause severe neurological manifestations if untreated 3, 4
Secondary Micronutrient Deficiencies
Vitamin D Deficiency
- Vitamin D deficiency is the most prevalent micronutrient deficiency in chronic atrophic autoimmune gastritis patients, affecting the majority of patients 5
- Vitamin D levels correlate directly with vitamin B-12 levels, suggesting shared pathogenic mechanisms 5
- Vitamin D levels are significantly lower in patients with macronodular ECL cell hyperplasia compared to those with linear or micronodular patterns 5
Other Deficiencies
- Folic acid deficiency occurs less commonly but has been documented in atrophic gastritis patients 3, 5
- Vitamin C deficiency has been increasingly recognized in chronic atrophic autoimmune gastritis 3
- Calcium malabsorption can occur secondary to hypochlorhydria and vitamin D deficiency 3
Clinical Approach to Screening
Mandatory Screening
- All patients with atrophic gastritis, regardless of etiology, should be evaluated for iron and vitamin B-12 deficiency, especially if corpus-predominant disease is present 1
- Conversely, patients presenting with unexplained iron or vitamin B-12 deficiency should be evaluated for atrophic gastritis as the underlying cause 1
Risk Stratification by Etiology
- Autoimmune gastritis carries higher risk for micronutrient deficiencies than H. pylori-related atrophic gastritis 2
- Autoimmune gastritis patients have a 2.9-fold increased risk of iron deficiency compared to controls 2
- Age, sex, and H. pylori status do not significantly affect the occurrence of these deficiencies once atrophic gastritis is established 2
Important Clinical Pitfalls
Multiple Deficiencies
- Multiple vitamin deficiencies commonly coexist in atrophic gastritis patients and can lead to severe hematological, neurological, and skeletal manifestations 3
- In one study, 52 of 76 patients with nutritional deficiencies had multiple deficiencies rather than isolated ones 5
Timing of Deficiencies
- Iron deficiency manifests earlier than vitamin B-12 deficiency because the body has substantial hepatic stores of vitamin B-12 that can last years, whereas iron stores deplete more rapidly 1