Selenium is a trace mineral that is essential to good health but required only in small amounts.
Selenium is incorporated into proteins to make selenoproteins, which
are important antioxidant enzymes. The antioxidant properties of
selenoproteins help prevent cellular damage from free radicals. Free
radicals are natural by-products of oxygen metabolism that may
contribute to the development of chronic diseases such as cancer and
heart disease. Other selenoproteins help regulate thyroid function and play a role in the immune system.
Foods that Provide Selenium
Plant
foods are the major dietary sources of selenium in most countries
throughout the world. The content of selenium in food depends on the
selenium content of the soil where plants are grown or animals are
raised.
Selenium also can be found in some meats and seafood. Animals that eat
grains or plants that were grown in selenium-rich soil have higher
levels of selenium in their muscle. In the U.S., meats and bread are
common sources of dietary selenium. Some nuts are also sources of selenium.
Selenium content of foods can vary. For example, Brazil nuts may
contain as much as 544 micrograms of selenium per ounce. They also may
contain far less selenium. It is wise to eat Brazil nuts only
occasionally because of their unusually high intake of selenium.
Selected food sources of selenium include:
| Food | Micrograms
(μg) | Percent
DV* |
| Brazil nuts, dried, unblanched, 1 ounce |
544 |
780 |
| Tuna, light, canned in oil, drained, 3 ounces |
63 |
95 |
| Beef, cooked, 3½ ounces |
35 |
50 |
| Spaghetti w/ meat sauce, frozen entrée, 1 serving |
34 |
50 |
| Cod, cooked, 3 ounces |
32 |
45 |
| Turkey, light meat, roasted, 3½ ounces |
32 |
45 |
| Beef chuck roast, lean only, roasted, 3 ounces |
23 |
35 |
| Chicken Breast, meat only, roasted, 3½ ounces |
20 |
30 |
| Noodles, enriched, boiled, 1/2 cup |
17 |
25 |
| Macaroni, elbow, enriched, boiled, 1/2 cup |
15 |
20 |
| Egg, whole, 1 medium |
14 |
20 |
| Cottage cheese, low fat 2%, 1/2 cup |
12 |
15 |
| Oatmeal, instant, fortified, cooked, 1 cup |
12 |
15 |
| Rice, white, enriched, long grain, cooked, 1/2 cup |
12 |
15 |
| Rice, brown, long-grained, cooked, 1/2 cup |
10 |
15 |
| Bread, enriched, whole wheat, commercially prepared, 1 slice |
10 |
15 |
| Walnuts, black, dried, 1 ounce |
5 |
8 |
| Bread, enriched, white, commercially prepared, 1 slice |
4 |
6 |
| Cheddar cheese, 1 ounce |
4 |
6 |
*DV = Daily
Value. DVs are reference numbers developed by the Food and Drug
Administration (FDA) to help consumers determine if a food contains a
lot or a little of a specific nutrient. The DV for selenium is 70
micrograms (ug). Most food labels do not list a food's selenium
content. The percent DV (%DV) listed on the table indicates the
percentage of the DV provided in one serving. A food providing 5% of
the DV or less is a low source while a food that provides 10-19% of the
DV is a good source. A food that provides 20% or more of the DV is high
in that nutrient. It is important to remember that foods that provide
lower percentages of the DV also contribute to a healthful diet. For
foods not listed in this table, please refer to the U.S. Department of
Agriculture's Nutrient Database Web site: http://www.nal.usda.gov/fnic/cgi-bin/nut_search.pl.
Selenium Recommended Dietary Allowance (RDA)
The RDA recommends the average daily dietary intake level that is
sufficient to meet the nutrient requirements of nearly all (97-98%)
healthy individuals in each age and gender group.
Selenium Recommended Dietary Allowances (RDA) for
Age
(years) | Males and Females
(μg/day) | Pregnancy
(μg/day) | Lactation
(μg/day) |
| 1-3 y |
20 |
N/A |
N/A |
| 4-8 y |
30 |
N/A |
N/A |
| 9-13 y |
40 |
N/A |
N/A |
| 14-18 y |
55 |
60 |
70 |
| 19 y + |
55 |
60 |
70 |
Selenium Deficiency
Human
selenium deficiency is rare in the U.S. but is seen in other countries,
most notably China, where soil concentration of selenium is low.
There is evidence that selenium deficiency may contribute to
development of a form of heart disease, hypothyroidism, and a weakened
immune system.
There is also evidence that selenium deficiency does not usually cause
illness by itself. Rather, it can make the body more susceptible to
illnesses caused by other nutritional, biochemical or infectious
stresses.
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Nutrition 
