Selenium is a micronutrient that plays an important role in the oxidative defense of cells and DNA against damage by harmful free radicals. Selenium is the main component of the selenoproteins that play important roles in reproductive function, immune system modulation, and thyroid hormone synthesis [Sahebari].
Low Serum Selenium Levels and Autoimmune Diseases
Decreased serum selenium levels have been associated with increased incidence of some autoimmune diseases. Furthermore, low levels of selenium may be a risk factor for systemic inflammation and for the initiation of some autoimmune diseases [Sahebari]:
- Rheumatoid arthritis
- Sjögren syndrome
- Behcet’s diseases
- Scleroderma (systemic sclerosis)
Selenium Supplementation and Autoimmune Diseases
Selenium supplementation has been shown to have beneficial effects in the management of rheumatoid arthritis and scleroderma [Sahebari].
Selenium supplementation may reduce the incidence and severity of some other autoimmune diseases through its role in the maintenance of thyroid function and through its anti-inflammatory effects [Sahebari].
There is a need for more clinical research into the impact of selenium supplementation on immune system function generally and into the impact of selenium supplementation on the risk of developing autoimmune diseases in particular [Sahebari].
Selenium and Autoimmune Diseases: The Evidence
Researchers reviewed the results of 32 published medical journal articles on the topic of selenium and autoimmune diseases. A majority of the articles showed an improvement in the clinical symptoms of autoimmune diseases after treatment of patients with varying dosages of l-selenomethionine, which is the primary species of selenium found in high-selenium yeast preparations [Sahebari].
The researchers’ review of the medical journal literature showed that low serum selenium concentrations are not uncommon in patients with autoimmune diseases [Sahebari].
At present, it is not clear whether the selenium deficiency found in patients with autoimmune diseases is a cause or a consequence (or both) of the development of the autoimmune diseases [Sahebari].
Selenium and Rheumatoid Arthritis
Research shows elevated levels of oxidative stress and reduced levels of blood antioxidants in patients with rheumatoid arthritis. Selenium deficiency may be a factor in the development of rheumatoid arthritis. Selenium supplementation alleviates symptoms and reduces inflammation levels in patients with rheumatoid arthritis [Sahebari].
Selenium and Systemic Lupus Erythematosus (SLE)
Serum selenium concentrations are low in patients diagnosed with SLE. The precise effect of selenium on SLE patients is not known at present. An animal study has shown that selenium supplementation has significant effects on natural killer cell activity in mice with SLE [Sahebari].
Selenium and Sjögren Syndrome
Studies have shown that serum selenium levels are low in untreated Sjögren syndrome patients, especially in older patients. One study has shown that supplementation of Sjögren syndrome patients with selenium and vitamin E stopped the disease progression in some but not all patients. There is insufficient evidence at present about the effect of selenium on Sjögren syndrome patients [Sahebari].
Selenium and Behcet’s Disease
Studies have shown that the serum selenium level in Behcet’s disease patients is much lower than in normal healthy controls. One study has shown that selenium deficiency is associated with impeded immune response in extra-cellular body fluids. However, the exact effect of selenium supplementation of Behcet’s disease patients is unknown [Sahebari].
Selenium and Scleroderma (Systemic Sclerosis)
Patients with scleroderma have generally low selenium levels. One study has shown low levels of the selenium containing antioxidant enzyme glutathione peroxidase in patients with scleroderma. There is a documented correlation between serum selenium concentration and scleroderma disease progression. Selenium supplementation may lessen the extent of the disease progression [Sahebari].
Conclusion: More Research on Selenium and Autoimmune Diseases is Needed
More research into the antioxidant and anti-inflammatory effects of selenium supplementation on the initiation of autoimmune diseases and on the clinical improvement of the symptoms of autoimmune diseases is needed. Selenium supplementation may have beneficial effects, especially antioxidant and anti-inflammatory effects, on some autoimmune diseases [Sahebari].
Sources
Sahebari, M, Rezaieyazdi, Z & Khodashi, M. (2019). Selenium and autoimmune diseases: a review. Current Rheumatology Reviews, 15: 123-134.
The information contained in this review article is not intended as medical advice and should not be used as such.
15 August 2019