Why deficiencies matter: Even after starting a gluten-free diet, nutritional deficiencies can persist for months or years while the intestine heals. Addressing them proactively — through diet, supplementation, and monitoring — is a core part of celiac disease management.
The duodenum — the section of the intestine most damaged in celiac disease — is where iron is primarily absorbed. Villous atrophy here severely impairs iron uptake.
Iron-rich foods (red meat, legumes, dark leafy greens) combined with Vitamin C to enhance absorption. Supplementation is often required until intestinal healing is confirmed.
Fat-soluble vitamins including D require healthy gut mucosa for absorption. Damaged villi significantly reduce uptake, leading to deficiency even with adequate sun exposure.
Daily supplementation is almost always required. Levels should be monitored via blood test. Fatty fish, egg yolks, and fortified foods are dietary sources, but supplementation is typically essential.
Calcium absorption depends on Vitamin D and healthy gut epithelium. Both are compromised in active celiac disease. Long-term calcium deficiency leads to reduced bone density and increased fracture risk.
Dairy products, calcium-set tofu, broccoli, and fortified plant milks. Calcium supplements should be taken with Vitamin D for optimal absorption. Bone density scanning (DEXA) is recommended at diagnosis.
Folate is absorbed in the upper small intestine — precisely the region most affected by celiac-related damage. Many traditional folate-rich foods (fortified cereals and bread) also contain gluten, compounding the risk.
Leafy greens, legumes, avocado, and certified GF fortified foods. Supplementation is important, especially for women of childbearing age.
B12 absorption relies on intrinsic factor produced in the stomach and absorption in the terminal ileum. While the primary damage in celiac is in the duodenum, systemic inflammation and associated autoimmune gastritis can impair B12 uptake.
Animal products (meat, fish, eggs, dairy). Vegans and those with severe malabsorption may require injections or high-dose oral supplements. B12 deficiency can cause irreversible nerve damage if untreated.
Zinc is absorbed in the proximal small intestine and is commonly deficient in untreated celiac disease. It plays a critical role in immune function, wound healing, and taste perception.
Red meat, shellfish, legumes, nuts, and seeds. Supplementation should be guided by blood levels as excess zinc can interfere with copper absorption.
Malabsorption across the small intestine reduces magnesium uptake. Diarrhoea — a common symptom of active celiac — further depletes magnesium through gut losses.
Dark leafy greens, nuts, seeds, legumes, and dark chocolate. Magnesium glycinate supplements are well-tolerated and less likely to cause digestive discomfort.
Always test, don't guess
Nutritional deficiencies should be confirmed through blood tests before supplementing. Over-supplementing certain nutrients — particularly fat-soluble vitamins like A and D — can cause toxicity. Work with your gastroenterologist or dietitian to build a personalised supplementation plan.