Selenium
Other name(s):
selenious acid, selenium methylselenocysteine, selenomethionine, sodium selenite
General description
Selenium is an essential trace element and antioxidant. It’s a cofactor in enzyme
regulation. It also helps maintain the health of tissue and muscle. Selenium may help
treat and prevent prostate cancer.
Selenium has antioxidant effects. It may serve some of the same antioxidant functions
as vitamin E.
Medically valid uses
Selenium is needed to maintain the heart and blood vessels. It also keeps the heart
muscle and skin tissue healthy. It may also aid in the treatment and prevention of
cancer.
Selenium compounds are used in some shampoos. An example is selenium sulfide. It’s
used in this form to treat seborrhea and dandruff.
Unsubstantiated claims
There may be benefits that have not yet been proven through research.
Selenium may prevent aging of the skin. It also slows the aging process. It may enhance
immune system function. It may also protect against heart disease. It may also bind
to heavy metals and reduce the toxicity of mercury.
Recommended intake
Selenium is measured in micrograms (mcg). It’s available as 50 mcg to 200 mcg tablets.
The RDA is the recommended dietary allowance.
|
Group
|
RDA
|
|
Infants (0 to 6 months)
|
15 mcg*
|
|
Infants (7 months to 1 year)
|
20 mcg*
|
|
Children (1 to 3 years)
|
20 mcg
|
|
Children (4 to 8 years)
|
30 mcg
|
|
Children (9 to 13 years)
|
40 mcg
|
|
Children (14 to 18 years)
|
55 mcg
|
|
Adults (19 years and older)
|
55 mcg
|
|
Pregnancy
|
60 mcg
|
|
Breastfeeding
|
70 mcg
|
*Adequate Intake (AI)
|
Food source
|
Selenium content per 100 grams
|
|
Wheat germ
|
79 mcg
|
|
Brazil nuts
|
1912 mcg
|
|
Whole wheat bread
|
25.6 mcg
|
|
Oats, dry
|
28.8 mcg
|
|
Brown rice
|
5.8 mcg
|
|
Orange juice
|
0.1 mcg
|
*mcg = microgram
The amount of selenium in vegetables and grains depends on the soil in which they
are grown.
Selenium is suggested in doses of no more than 200 mcg per day. The treatment range
for selenium is narrow. You shouldn’t take too much. The recommended dose is 100 mcg
to 200 mcg per day.
Selenium deficiency can cause symptoms. These can include:
In parts of the world where selenium isn’t found in the soil and water, people may
develop Keshan disease. This is a form of cardiomyopathy. This condition is weakness
of the heart muscle. Selenium deficiency has also been seen in children with Kwashiorkor,
a protein malnutrition disorder.
Side effects, toxicity, and interactions
Getting selenium from food sources doesn’t seem to cause side effects. However, having
more than 200 mcg of selenium per day from supplements for an extended period of time
may cause side effects. These can include:
-
Itchy skin
-
Diarrhea
-
Weakening and loss of fingernails and hair
-
Discolored teeth
-
Nausea
-
Vomiting
-
Peripheral neuropathy
-
Severe tiredness (fatigue)
-
A garlic-like odor to your breath
Adults who work in industrialized areas with high selenium content have a higher chance
of liver and heart disease.
Even though optimal amounts of selenium may reduce the risk of cancer, having too
much can be harmful. It may increase the risk for cancer.
Women who are pregnant or breastfeeding should talk to their healthcare providers
before taking any supplements. Too much selenium can lead to bone and cartilage problems
in unborn babies.
Kidney problems can cause high selenium levels in the body.
There are no known food interactions with selenium. It can interact with some antibiotics.
It can also interact with some medicines used to treat osteoporosis.
Talk to your healthcare provider about selenium before taking it.