# Micronutrients in Autoimmune Diseases: Shining a Light on Vitamin D, Cobalamin, Folate, and Iron Metabolism

**Authors:** Paola Triggianese, Giuseppe A. Ramirez, Francesca Cedola, Stefania Nicola, Giulia Costanzo, Luisa Brussino, Francesca Chiereghin, Davide Firinu, David Della-Morte, Vincenzo Patella, Cinzia Milito

PMC · DOI: 10.3390/nu18040561 · 2026-02-08

## TL;DR

This paper reviews how vitamin D, B12, folate, and iron deficiencies contribute to autoimmune diseases and suggests that addressing these deficiencies could improve treatment outcomes.

## Contribution

The paper highlights the role of micronutrient deficiencies in autoimmune disease progression and advocates for routine screening and supplementation.

## Key findings

- Micronutrient deficiencies are common in autoimmune disease patients and worsen immune dysregulation and inflammation.
- Vitamin D, B12, folate, and iron each have distinct immunomodulatory roles in autoimmune disease pathogenesis.
- Targeted micronutrient supplementation may offer adjunctive benefits in managing autoimmune diseases.

## Abstract

Background: Autoimmune diseases (AIDs) are characterized by chronic inflammation and tissue damage resulting from abnormal immune responses. While genetic and environmental factors play significant roles in disease development, essential micronutrient deficiencies (MNDs) represent a critical and often overlooked contributor. Methods: This review examines the interactions between micronutrients and immune cells, focusing on vitamin D, vitamin B12, folate (FA), and iron, and their roles in AIDs, such as rheumatoid arthritis, autoimmune thyroid disorders, multiple sclerosis, systemic lupus erythematosus, and other connective tissue diseases. We explore the immunomodulatory effects of these micronutrients, their impact on immune tolerance, and the mechanisms by which MNDs contribute to disease progression. Results: MNDs are commonly observed in patients with AIDs and are associated with worsening immune dysregulation, increased inflammation, and disease severity. Vitamin D plays a pivotal role in modulating immune responses and attenuating inflammation, while iron and FA are essential for immune cell proliferation and function. Vitamin B12 supports methylation processes and genomic stability. Conclusions: MNDs significantly influence the pathogenesis and progression of AIDs. Routine micronutrient screening and targeted supplementation should be considered as part of clinical management, offering potential adjunctive benefits alongside conventional therapies. Further research is needed to define optimal dosing strategies and to identify patient subgroups most likely to benefit from nutrition-based interventions.

## Linked entities

- **Chemicals:** vitamin B12 (PubChem CID 73415824), folate (PubChem CID 135405876), iron (PubChem CID 23925)
- **Diseases:** rheumatoid arthritis (MONDO:0008383), multiple sclerosis (MONDO:0005301), systemic lupus erythematosus (MONDO:0007915), connective tissue diseases (MONDO:0003900)

## Full-text entities

- **Genes:** NFKB1 (nuclear factor kappa B subunit 1) [NCBI Gene 4790] {aka CVID12, EBP-1, KBF1, NF-kB, NF-kB1, NF-kappa-B1}, CD4 (CD4 molecule) [NCBI Gene 920] {aka CD4mut, IMD79, Leu-3, OKT4D, T4}, TPO (thyroid peroxidase) [NCBI Gene 7173] {aka MSA, TDH2A, TPX}, IFNG (interferon gamma) [NCBI Gene 3458] {aka IFG, IFI, IMD69}, HAMP (hepcidin antimicrobial peptide) [NCBI Gene 57817] {aka HEPC, HFE2B, LEAP1, PLTR}, DEFB4B (defensin beta 4B) [NCBI Gene 100289462] {aka DEFB4P}, DHFR (dihydrofolate reductase) [NCBI Gene 1719] {aka DHFR1, DYR}, IL6 (interleukin 6) [NCBI Gene 3569] {aka BSF-2, BSF2, CDF, HGF, HSF, IFN-beta-2}, TG (thyroglobulin) [NCBI Gene 7038] {aka AITD3, TGN}, IL17A (interleukin 17A) [NCBI Gene 3605] {aka CTLA-8, CTLA8, IL-17, IL-17A, IL17, ILA17}, IL10 (interleukin 10) [NCBI Gene 3586] {aka CSIF, GVHDS, IL-10, IL10A, TGIF}, TNF (tumor necrosis factor) [NCBI Gene 7124] {aka DIF, IMD127, TNF-alpha, TNFA, TNFSF2, TNLG1F}, CD8A (CD8 subunit alpha) [NCBI Gene 925] {aka CD8, CD8alpha, IMD116, Leu2, p32}, VDR (vitamin D receptor) [NCBI Gene 7421] {aka NR1I1, PPP1R163}
- **Diseases:** thyroid dysfunction (MESH:D013959), ATD (MESH:D013967), respiratory insufficiency (MESH:D012131), IBD (MESH:D015212), AIDs (MESH:D001327), B12 Deficiency (MESH:D014806), fatigue (MESH:D005221), hepatic toxicity (MESH:D056486), Vitamin D deficiency (MESH:D014808), Subclinical hypothyroidism (MESH:D058345), immune-mediated disorders (MESH:C567355), SpA (MESH:D013167), T1D (MESH:D003922), MS (MESH:D009103), dysregulation (MESH:D021081), neurological deficits (MESH:D009461), immune dysregulation (OMIM:614878), autoinflammation (MESH:D056660), Iron-deficient anemia (MESH:D018798), psoriasis (MESH:D011565), autoimmune-mediated tissue damage (MESH:D017695), SLE (MESH:D008180), Hashimoto's thyroiditis (MESH:D050031), Graves' disease (MESH:D006111), impaired function (MESH:D003072), bone fragility (MESH:C536063), chronic (MESH:D002908), Iron deficiency (MESH:D000090463), absorption (MESH:C564600), axial skeleton (MESH:C537791), SSc (MESH:D012595), pulmonary hypertension (MESH:D006976), Inflammation (MESH:D007249), Gastrointestinal Symptom (MESH:D012817), injury to (MESH:D014947), neurodegeneration (MESH:D019636), anemia (MESH:D000740), RA (MESH:D001172), mouth ulcers (MESH:D019226), hypothyroid (MESH:D007037), MNDs (MESH:D007153), CRD (OMIM:120970), connective tissue diseases (MESH:D003240), malabsorption (MESH:D008286), ID (MESH:C537985), pulmonary arterial hypertension (MESH:D000081029), FA (MESH:C562799), neurocognitive dysfunction (MESH:D019965), lupus nephritis (MESH:D008181), calcinosis (MESH:D002114), Sjogren's Syndrome (MESH:D012859), thyroid insufficiency (MESH:D000309), dysbiosis (MESH:D064806), impaired immune function (MESH:D007154), bone marrow toxicity (MESH:D001855), gastrointestinal disturbance (MESH:D005767), Juvenile Idiopathic Arthritis (MESH:D001171), essential micronutrient deficiencies (MESH:D020329), sacroiliitis (MESH:D058566), neuroinflammatory (MESH:D000090862)
- **Chemicals:** eicosapentaenoic acid (MESH:D015118), B12 (MESH:C034730), MTX (MESH:D008727), Iron (MESH:D007501), arachidonic acid (MESH:D016718), nucleotide (MESH:D009711), docosahexaenoic acid (MESH:D004281), vanadium (MESH:D014639), Vitamin A (MESH:D014801), fluoride (MESH:D005459), retinoids (MESH:D012176), Cobalamin (MESH:D014805), iodine (MESH:D007455), S-adenosyl methionine (MESH:D012436), arsenate (MESH:C025657), 1,25-dihydroxyvitamin D3 (MESH:D002117), vitamin B6 (MESH:D025101), molybdenum (MESH:D008982), Vitamin C (MESH:D001205), copper (MESH:D003300), Magnesium (MESH:D008274), flavonoids (MESH:D005419), Manganese (MESH:D008345), FA (MESH:D005492), ROS (MESH:D017382), calcium (MESH:D002118), DHA (MESH:C027493), boron (MESH:D001895), SCFA (MESH:D005232), eicosanoids (MESH:D015777), methionine (MESH:D008715), 25(OH) vitamin D (-), secosteroid (MESH:D012632), Vitamin D (MESH:D014807), curcumin (MESH:D003474), phosphorus (MESH:D010758), salt (MESH:D012492), phosphate (MESH:D010710), potassium (MESH:D011188), sugars (MESH:D000073893), methylmalonyl-CoA (MESH:C015357), ACPA (MESH:C086759), Zn (MESH:D015032), sodium (MESH:D012964), chromium (MESH:D002857), homocysteine (MESH:D006710), Vitamin E (MESH:D014810), amino acid (MESH:D000596), chlorine (MESH:D002713), sulforaphane (MESH:C016766), succinyl-CoA (MESH:C012046), selenium (MESH:D012643), carbon (MESH:D002244)
- **Species:** Homo sapiens (human, species) [taxon 9606], Bifidobacterium (genus) [taxon 1678], Lactobacillus (genus) [taxon 1578]

## Figures

2 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12943589/full.md

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Source: https://tomesphere.com/paper/PMC12943589