Selenium is a mineral that your body needs in small amounts to maintain good health. Although selenium deficiency is rare -- especially in the United States -- it may cause serious health problems, including poor immune function, heart disease or reduced thyroid hormone production, warns the Office of Dietary Supplements, or ODS. If you aren't getting enough selenium in your diet, your doctor may recommend treatment with a selenium supplement. Talk with your doctor about the benefits and risks associated with selenium supplements before you begin treatment.
Benefits
In addition to treating selenium deficiency, selenium supplements may help reduce your risk of heart disease, cancer, asthma and rheumatoid arthritis. These conditions are all associated with low blood levels of selenium. Selenium supplementation may also improve male fertility, although unusually high blood levels of selenium may reduce sperm motility. Research regarding the use of selenium supplements in people with HIV is controversial. In a November 2010 article published in the journal "Nutrition Review," Cosby Stone, M.D., and colleagues reviewed a number of studies evaluating the role of selenium in HIV infection. Stone noted that while several studies demonstrated that selenium may slow the reproduction and growth of the virus, separate studies have alternatively found selenium supplementation to have no effect on HIV. Additional research is necessary to further examine these purported benefits of selenium supplement.
Dosage
The ODS recommends adults receive between 55 and 70 mcg of selenium each day. Your doctor may also recommend short-term treatment with 200 mcg selenium supplements, depending on your individual health condition. Taking more than 400 mcg of selenium may increase your risk of developing selenium toxicity and may induce overdose symptoms.
Side Effects
Short-term treatment with selenium supplements is generally not associated with side effects. If you take more than 400 mcg of selenium daily, you may experience side effects, such as irritability, diminished energy, nausea, vomiting and nail changes, warns MedlinePlus, an online resource of the National Institutes of Health. Prolonged treatment with high doses of selenium may also cause tremors, facial flushing, odorous breath, fatigue, oral metallic taste, hair loss and lightheadedness. Seek prompt care from your medical provider if you develop any of these side effects while taking selenium.
Contraindications
Discuss all pre-existing health problems you may have with your medical provider before taking selenium supplements. If you have an underactive thyroid -- a condition called hypothyroidism -- or a personal or family history of skin cancer, do not take selenium unless otherwise instructed by your doctor. Avoid taking selenium supplements if you have diabetes or high cholesterol, as high doses of selenium may exacerbate your condition.
Medication Interactions
Talk with your physician about all medications you are currently taking before you begin treatment with selenium. Concomitant use of selenium and anticoagulants may increase your risk of bleeding or bruising. Selenium may also prolong the sedative effects of barbiturates, such as butabarbital and phenobarbital. The University of Maryland Medical Center also warns that taking selenium in conjunction with cholesterol-lowering medication may reduce the effectiveness of such drugs.
