Can celiac disease present primarily as iron deficiency?

Celiac disease (CD) is frequently identified as a primary or sole clinical manifestation of iron deficiency (ID) or iron deficiency anemia (IDA), often occurring in the absence of classic gastrointestinal symptoms such as diarrhea or weight loss.

Clinical effectiveness and prevalence

Iron deficiency is the most common extraintestinal manifestation of celiac disease. Research indicates that between 12% and 82% of newly diagnosed CD patients present with IDA.

• Prevalence in IDA populations: Systematic reviews and meta-analyses show that approximately 3.2% of patients with unexplained IDA have biopsy-confirmed celiac disease. In populations with refractory or obscure-origin IDA, this prevalence increases to 5.5%–8%.
• Clinical presentation: Because IDA can be the only sign of celiac disease, clinical guidelines from organizations such as the American College of Gastroenterology (ACG) and the British Society of Gastroenterology (BSG) strongly recommend screening for CD in any patient with unexplained or refractory iron deficiency.

Mechanistic explanations

The link between celiac disease and iron deficiency is rooted in the structural and molecular physiology of the digestive tract.

• Anatomical site: Dietary iron is primarily absorbed in the proximal small intestine, specifically the duodenum. This is also the region where gluten-induced immune damage is typically most severe in celiac disease.
• Villous atrophy: The autoimmune response to gluten leads to the destruction of the mucosal architecture, known as villous atrophy. This flattening of the intestinal villi drastically reduces the surface area available for nutrient uptake.
• Transporter disruption: The damage destroys the enterocytes (intestinal cells) that house critical iron transporters, such as Divalent Metal Transporter 1 (DMT1) and ferroportin. Without these specialized proteins and a healthy mucosal surface, the body cannot effectively capture iron from dietary sources, leading to systemic depletion over time.

Bottom line

Celiac disease is a leading cause of unexplained iron deficiency because the autoimmune damage specifically targets the duodenum, the body's primary site for iron absorption. Screening for celiac disease is essential for patients with iron deficiency, even if they do not experience typical digestive symptoms.