Micronutrients support many aspects of immune function, including:
- Immune cell signaling
- Cytokine production
- Antioxidant defense
- Immune cell differentiation
- Regulation of inflammatory pathways
Autoimmune diseases occur when immune tolerance breaks down and immune cells begin attacking the body’s own tissues. Researchers have identified several immune pathways involved in this process, including the balance between inflammatory immune responses and regulatory immune responses.
Some micronutrients appear to influence these pathways, which has led researchers to explore their potential role in autoimmune disease.¹
However, a key challenge in interpreting this research is determining cause versus consequence. Autoimmune diseases can affect nutrient absorption, metabolism, appetite, and dietary intake. As a result, nutrient differences observed in people with autoimmune conditions may reflect disease effects rather than underlying causes.
Zinc and Immune Regulation
Zinc is an essential trace element involved in many immune processes.
Within immune cells, zinc functions as a signaling molecule that influences pathways involved in T-cell activation and cytokine production.¹²
One immune pathway frequently discussed in autoimmune research involves the balance between:
- Th17 cells, which promote inflammatory immune responses
- Regulatory T cells, which help maintain immune tolerance
Disruption of this balance has been implicated in several autoimmune diseases. Zinc appears to influence these immune pathways and may help regulate inflammatory signaling.¹
Researchers have also observed lower circulating zinc levels in several autoimmune diseases, including rheumatoid arthritis and multiple sclerosis.¹
However, most of the evidence in this area comes from mechanistic studies, animal models, or observational research. Large clinical trials examining zinc supplementation in autoimmune disease are still limited.
Food Sources of Zinc
- Oysters and other shellfish
- Beef and poultry
- Pumpkin seeds
- Legumes
- Nuts
- Whole grains
Vitamin D and Immune Tolerance
Vitamin D is another nutrient frequently studied in autoimmune disease.
Unlike many vitamins, vitamin D functions more like a hormone. Many immune cells — including T cells, B cells, and dendritic cells — express the vitamin D receptor, allowing vitamin D to influence immune cell activity and gene expression.¹
Mechanistically, vitamin D appears to:
- Reduce pro-inflammatory Th17 responses
- Promote regulatory T-cell activity
- Support immune tolerance
Observational studies have found associations between low vitamin D levels and several autoimmune diseases.
However, clinical trials examining vitamin D supplementation have produced mixed results. Systematic reviews of dietary interventions in rheumatoid arthritis report inconsistent improvements in clinical outcomes.³⁴
This means vitamin D clearly plays a role in immune biology, but its role as a treatment strategy remains uncertain.
Food Sources of Vitamin D
- Fatty fish such as salmon and sardines
- Fortified dairy products
- Fortified plant milks
- Egg yolks
- Fortified cereals
Sunlight exposure also contributes to vitamin D production in the skin.
Omega-3 Fatty Acids and Rheumatoid Arthritis
Omega-3 fatty acids are among the most extensively studied nutritional interventions for rheumatoid arthritis.
The omega-3 fatty acids most commonly examined are EPA and DHA, which are found in fatty fish and fish oil supplements.
Omega-3 fatty acids influence inflammatory signaling by altering the production of eicosanoids — molecules that play a role in inflammatory responses.⁵
Some randomized trials have reported modest improvements in rheumatoid arthritis symptoms such as:
- Joint pain
- Morning stiffness
- Reduced use of NSAIDs
However, systematic reviews and umbrella reviews of randomized trials report heterogeneous results and generally modest clinical effects.³⁴
For this reason, omega-3 fatty acids are generally considered supportive nutritional strategies rather than primary treatments.
Food Sources of Omega-3 Fatty Acids
- Salmon
- Sardines
- Mackerel
- Anchovies
- Walnuts
- Chia seeds
- Flax seeds
Selenium and Autoimmune Thyroid Disease
Selenium plays an important role in thyroid health.
The thyroid gland contains one of the highest selenium concentrations in the body because selenium is incorporated into selenoproteins that help regulate thyroid hormone metabolism and protect thyroid tissue from oxidative stress.⁶⁷
Oxidative stress is thought to contribute to autoimmune thyroid diseases such as Hashimoto’s thyroiditis.
Some studies suggest selenium supplementation may reduce thyroid antibody levels in certain individuals with Hashimoto’s disease.
However, many studies measure changes in antibody levels rather than meaningful clinical outcomes, such as symptoms or disease progression.⁸ Because of this, the clinical significance of selenium supplementation remains an area of ongoing research.
Food Sources of Selenium
- Brazil nuts
- Seafood
- Eggs
- Poultry
- Whole grains
Iodine and Thyroid Autoimmunity
Iodine is essential for thyroid hormone production.
However, unlike many nutrients, both deficiency and excess intake can affect thyroid health. High iodine intake has been associated with increased risk of autoimmune thyroid disease in genetically susceptible individuals.⁹
This highlights an important principle in nutrition and autoimmune disease: more is not always better. Maintaining appropriate nutrient intake ranges is often more important than increasing intake above typical levels.
Food Sources of Iodine
- Iodized salt
- Seafood
- Dairy products
- Seaweed
Key Takeaways
Micronutrients clearly play important roles in immune function. Nutrients such as zinc, vitamin D, selenium, and omega-3 fatty acids influence immune signaling, inflammation, and oxidative stress.
However, much of the research in this area focuses on biologic mechanisms and associations, rather than definitive clinical treatments.
For people living with autoimmune disease, nutrition can support overall health and complement medical care — but it is rarely a stand-alone treatment strategy. Understanding these nutrient-immune interactions helps researchers better understand autoimmune disease biology and may eventually inform more targeted therapies in the future.
References
- Wessels I, Rink L. Micronutrients in autoimmune diseases: possible therapeutic benefits of zinc and vitamin D. J Nutr Biochem. 2020;77:108240.
- Bonaventura P, Benedetti G, Albarède F, Miossec P. Zinc and its role in immunity and inflammation. Autoimmun Rev. 2015;14(4):277-285.
- Philippou E, Petersson SD, Rodomar C, Nikiphorou E. Rheumatoid arthritis and dietary interventions: systematic review of clinical trials. Nutr Rev. 2021;79(4):410-428.
- Cheng XE, Hu X, Tang J, et al. Effects of nutritional supplements and dietary interventions on rheumatoid arthritis: an umbrella review of meta-analyses of randomized controlled trials. Autoimmun Rev. 2025.
- Nikiphorou E, Philippou E. Nutrition and its role in prevention and management of rheumatoid arthritis. Autoimmun Rev. 2023;22(7):103333.
- Hu S, Rayman MP. Multiple nutritional factors and the risk of Hashimoto’s thyroiditis. Thyroid. 2017;27(5):597-610.
- Rayman MP. Multiple nutritional factors and thyroid disease, with particular reference to autoimmune thyroid disease. Proc Nutr Soc. 2019;78(1):34-44.
- Morasiewicz-Jeziorek J, Buczyńska A, Krętowski AJ, Adamska A. The role of immunological challenges, oxidative stress, and dietary interventions in managing Hashimoto’s thyroiditis: a narrative review. Nutr Rev. 2026.
- Duntas LH. Nutrition and thyroid disease. Curr Opin Endocrinol Diabetes Obes. 2023;30(6):324-329.
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This article is for informational purposes only and is not intended as medical advice. Before incorporating any of these suggestions, consult with a qualified healthcare professional. If you are seeking personalized guidance, schedule a consultation with me, an integrative registered dietitian nutritionist (RDN), to ensure you make safe, evidence-based choices.