Which nutrient deficiency is commonly associated with untreated celiac disease?

Celiac disease is an autoimmune disorder that causes a severe reaction to gluten, leading to damage in the small intestine. This damage affects the intestine's ability to absorb nutrients effectively. Among the various nutrient deficiencies associated with untreated celiac disease, iron deficiency is particularly common.

The malabsorption caused by the intestinal damage results in inadequate absorption of several key nutrients, with iron being one of the most impacted. Iron is crucial for the production of hemoglobin, which is necessary for transporting oxygen in the blood. Without proper absorption, individuals can develop iron deficiency anemia, resulting in fatigue, weakness, and other health issues.

While deficiencies in vitamin D, vitamin C, and zinc can also occur due to malabsorption, the prevalence and significance of iron deficiency in individuals with untreated celiac disease highlight its importance. Iron is especially vital for those with increased needs, such as women of childbearing age. Thus, the connection between celiac disease and iron deficiency stands out, making this the correct answer.