09/02/2026
If your child has autoimmune disease and is exhausted, there's a good chance something nutritional is contributing.
𧬠1. Vitamin D
The most common deficiency in pediatric autoimmune disease. One study of children with JIA found 67% were vitamin D deficient. Higher methotrexate doses correlated with lower vitamin D levels.
𧬠2. Iron and ferritin
Iron deficiency is common in pediatric autoimmune disease. In pediatric IBD, up to 88% of kids are iron-deficient at diagnosis. Similar patterns show up across other pediatric autoimmune conditions due to chronic inflammation.
What makes iron tricky in autoimmune disease: inflammation causes the body to sequester iron through a process called anemia of chronic inflammation. Ferritin can also be falsely elevated by inflammation, making deficiency easier to miss. That's why full iron studies (iron, ferritin, transferrin saturation, and sometimes a reticulocyte hemoglobin) are more useful than ferritin alone.
Low iron contributes to fatigue, brain fog, headaches, dizziness, hair loss, and restless legs.
𧬠3. Folate (B9)
If your child is on methotrexate, this is essential. Methotrexate works in part by blocking folate, which is also why folate deficiency is a common side effect.
Folate supplementation is standard of care for most kids on methotrexate. Untreated folate deficiency can cause mouth ulcers, GI upset, hair thinning, fatigue, and elevated liver enzymes.
For kids who don't tolerate folic acid well, folinic acid (a different form, sometimes called leucovorin) is an evidence-based alternative.
𧬠4. Vitamin B12
Less commonly deficient than iron or vitamin D, but worth checking in kids who are vegetarian, vegan, or on long-term acid-suppressing medications.
B12 deficiency can cause fatigue, brain fog, tingling, and mood symptoms. Routine bloodwork doesn't always include it.
𧬠5. Zinc
Often overlooked. In pediatric IBD, zinc deficiency runs 10-53%. It can also be low in other autoimmune conditions where gut absorption is affected.
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