Selenium
Known for making special proteins that are antioxidant enzymes, selenium is a trace mineral commonly found in plant food sources as well as animal food sources. Experiencing a deficiency or receiving too much selenium is rare.
Selenium benefits
The primary benefits of selenium are it's ability to make special proteins known as selenoproteins that fall into the antioxidant enzyme category. Selenoproteins assist in preventing cellular damage as well as assisting in the regulation of thyroid function and protecting the body while receiving a vaccination.
Medical studies suggest that selenium may also prevent certain types of cancer, aid in preventing cardiovascular disease, and protecting the body from poisonous heavy metals. For males, selenium may provide a fertility boost by means of improved sperm production and sperm movement.
Sources of selenium
Selenium is found in both plant and animal food sources. When found in plants, the amount of selenium varies greatly dependent on the amount of selenium found in the soil. Plant sources of selenium include:
- Nuts (it should be noted at Brazil nuts can contain abnormally high amounts of selenium and should be consumed sparingly)
- Seeds
- Oats
- Breads
- Rice
Animal based sources of selenium include:
- Tuna
- Cod
- Turkey
- Chicken
- Beef
- Eggs
Recommended amounts
Set forth by the Institute of Medicine, the Recommended Dietary Allowances (RDA) for selenium are below (some individuals may be placed on a plan that requires higher than normal amounts to manage a specific issue they may be experiencing).
| Table 1: Recommended Dietary Intakes for Selenium1 | ||||||
| Age | Amount | |||||
| 0-6 months | 15mcg/day (Adequate Intake) | |||||
| 7-12 months | 20mcg/day (Adequate Intake) | |||||
| 1-3 years | 20mcg/day | |||||
| 4-8 years | 30mcg/day | |||||
| 9-13 years | 40mcg/day | |||||
| 14+ years | 55mcg/day | |||||
| Pregnant Females | 60mcg/day | |||||
| Nursing Females | 70mcg/day | |||||
Selenium side effects
Due to the small amount of selenium needed per day, it is very rare for one to suffer a deficiency of selenium. Keshan disease (leading to abnormalities with the heart), Kashin-Beck disease (results in bone and joint disease), and Myxedematous endemic cretinism (results in mental retardation) are possible outcomes for those who are deficient in selenium2. Gastrointestinal issues such as Crohn's disease or if part of the stomach has been surgically removed may result in a selenium depletion or deficiency due to the body being unable to absorb the mineral.
While a rarity, an overabundance of selenium in the diet may cause a condition known as selenosis. This may result in hair loss, nail issues, nausea, irritability, fatigue, and mild nerve damage.
Sources:
1Selenium - http://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/
2Selenium in diet - All Information - http://www.umm.edu/ency/article/002414all.htm