Selenium Dietary Supplement Fact Sheet

Selenium refers to a trace mineral naturally found in many foods, such as Brazil nuts. Some people take selenium supplements to improve their health. Selenium may increase the ability of antioxidants to protect your body’s cells, according to Medline Plus.


Selenium is found in a variety of plant products and meats, such as tuna, beef, chicken, pasta and oatmeal. The amount of selenium in foods varies according the selenium content in the soil or local ecosystem.


Adults should consume at least 55 micrograms of selenium each day, according to the National Institutes of Health. Selenium deficiency is rare in the United States.


Selenium supplements are “likely effective” in preventing or treating selenium deficiency, according to Natural Medicines Comprehensive Database ratings cited by the National Institutes of Health. Selenium deficiency, resulting from very low selenium consumption, can cause heart problems and mental retardation. Selenium supplements are considered “possibly ineffective” for preventing cancer, heart disease and diabetes.


Consuming too much selenium leads to selenosis, which causes nausea, vomiting, garlic breath odor, fatigue and white or blotchy nails. Long-term consumption of selenium supplements may also increase the chance of developing type 2 diabetes or skin cancer, according to Medline Plus.

Selenium refers to a trace mineral naturally found in many foods