Can celiac disease cause iron deficiency and does HLA‑DQ8 raise celiac risk?

Celiac disease is a chronic autoimmune disorder where the ingestion of gluten leads to immune-mediated damage of the small intestine. This damage directly causes nutrient malabsorption and is heavily influenced by specific genetic risk factors.

Clinical and effectiveness evidence

Iron deficiency anemia (IDA) is one of the most frequent non-digestive signs of celiac disease, affecting up to 46% of patients at the time of diagnosis. In many cases, it is the sole clinical indicator of the disease. Research indicates that iron levels typically normalize only after the introduction of a strict gluten-free diet, which allows the intestinal lining to regenerate. While most patients see a resolution of anemia, approximately 5–10% may experience persistent deficiency due to incomplete mucosal healing or concurrent inflammatory factors.

Mechanistic explanations

The link between celiac disease, iron deficiency, and genetics is driven by specific molecular pathways:

• Malabsorption mechanism: Iron absorption occurs primarily in the duodenum. In celiac disease, gluten triggers an inflammatory response that causes villous atrophy—the flattening of the finger-like projections in the gut. This significantly reduces the surface area and the number of enterocytes (intestinal cells) available to transport iron via proteins like Divalent Metal Transporter 1 (DMT1).
• Inflammatory blockade: Chronic inflammation in the gut increases interleukin-6 (IL-6), which stimulates the liver to produce hepcidin. Elevated hepcidin levels degrade ferroportin, the only known cellular iron exporter, effectively "locking" iron inside cells and preventing it from entering the bloodstream.
• Genetic susceptibility (HLA-DQ8): The HLA-DQ8 molecule (an MHC class II protein) is a critical genetic architect of this disease. It possesses a specific binding pocket that favors negatively charged, deamidated gluten peptides. When these peptides bind to HLA-DQ8, they are presented to CD4+ T cells, which then launch the inflammatory cascade that destroys the intestinal lining. While HLA-DQ8 is present in about 5–10% of celiac patients, its absence makes a diagnosis of celiac disease highly improbable.

Bottom line

Celiac disease is a primary cause of iron deficiency due to the destruction of the duodenal absorptive surface, and carrying the HLA-DQ8 gene significantly increases susceptibility by enabling the immune system to recognize and attack gluten peptides.