What vitamin deficiencies are associated with celiac disease?

Vitamin Deficiencies in Celiac Disease

Celiac disease produces deficiencies in iron, folate, vitamin B12, vitamin D, calcium, zinc, and fat-soluble vitamins (A, E, K), with iron deficiency being the most common extra-intestinal manifestation affecting up to 33% of patients even during treatment. 1, 2, 3

Primary Deficiencies at Diagnosis

Most Common Deficiencies

• Iron deficiency occurs in the majority of untreated patients and is the most common extra-intestinal sign of celiac disease, with deficiency persisting in 33% of measurements during follow-up despite gluten-free diet adherence 1, 3, 4
• Folate (folic acid) deficiency is common due to proximal small bowel involvement, affecting absorption of this water-soluble vitamin 1, 2, 3
• Vitamin B12 deficiency occurs in 41% of untreated celiac patients, contrary to older beliefs that it was uncommon, and may persist in 2.4% during follow-up 1, 5, 4
• Vitamin D deficiency affects more than 50% of celiac patients and is associated with bone disease in both adults and children 1, 2, 3

Additional Micronutrient Deficiencies

• Calcium deficiency is well-documented and contributes to bone disease, with calcium being limited in gluten-free diets 1, 2
• Zinc deficiency correlates with the severity of villous atrophy, with deficiency present in 8.1% of follow-up measurements 1, 4
• Vitamin K deficiency is associated with reduced bone mineral density and hypoprothrombinemia, as recognized by FDA labeling for vitamin K products 1, 6
• Copper levels decrease with more pronounced intestinal lesions 1
• Magnesium deficiency may persist even after mucosal healing, as gluten-free products contain lower magnesium than gluten-containing counterparts 1, 3

Fat-Soluble Vitamins

• Vitamin A (retinol) deficiency correlates with steatorrhea extent, though usually remains subclinical and normalizes with treatment alone 1
• Vitamin E levels correlate with total blood cholesterol and lipid concentrations 1

B-Complex Vitamins

• Vitamin B6 deficiency occurs even in patients taking supplements while following a gluten-free diet 1
• Thiamin, riboflavin, and niacin are lower in gluten-free products without enrichment 1

Critical Clinical Pitfalls

The gluten-free diet itself perpetuates nutritional deficiencies because gluten-free products in the United States are rarely enriched compared to wheat-containing products, creating a secondary nutritional challenge beyond the malabsorption 1, 2

Key Monitoring Points

• Vitamin B12 deficiency can occur without concomitant folate deficiency (only 31% of B12-deficient patients had concurrent folate deficiency), so both must be measured independently 5
• Ferritin interpretation requires caution in active disease, as values up to 100 μg/L may still indicate iron deficiency when inflammation is present, especially with transferrin saturation <20% 1
• Albumin is not appropriate for assessing malabsorption despite being commonly low in celiac disease, as it functions as an acute phase protein rather than a reliable nutritional marker 1

Treatment Approach

Iron Deficiency

• Treat with 100-200 mg elemental iron daily for minimum 3 months, taken with vitamin C to enhance absorption 7
• Recovery from iron-deficiency anemia is possible with gluten-free diet alone in many cases 1

Vitamin D Deficiency

• Initiate 50,000 IU cholecalciferol weekly for 8-12 weeks to achieve target levels above 30 ng/mL 8
• Transition to maintenance of 800-2,000 IU daily after achieving target 8
• Recheck 25(OH)D levels after 3 months of treatment 8

Vitamin B12 Deficiency

• Parenteral vitamin B12 may be necessary for symptomatic patients (such as those with acral paresthesia), though most normalize on gluten-free diet alone 5
• Measure vitamin B12 concentrations routinely before hematinic replacement 5

Calcium Supplementation

• Ensure 1,000-1,500 mg daily from diet plus supplements, taken in divided doses of no more than 600 mg at once for optimal absorption 8
• Separate calcium supplements by 2 hours from iron supplements 8

Vitamin K

• Consider supplementation in patients with documented deficiency or coagulation abnormalities, as celiac disease is an FDA-recognized indication for vitamin K therapy 6

Monitoring Strategy During Follow-Up

Screen for deficiencies at 3-6 month intervals initially, then adjust based on clinical response and disease activity 4

• Measure iron, ferritin, vitamin B12, folate, vitamin D, and calcium at diagnosis and during follow-up 1, 3, 4
• Consider screening for zinc, magnesium, vitamin K, and vitamin B6 in patients with persistent symptoms, poor wound healing, or extensive small bowel involvement 1
• Deficiencies persist in 21-33% of patients for iron and vitamin D even years after starting gluten-free diet, necessitating ongoing surveillance 4