Selenium - Function, Sources, and Deficiency

Selenium - Function, Sources, and Deficiency

Did you know that selenium is a vital trace element for our body? It is responsible for numerous functions and ensures a robust immune system. Selenium strengthens our cells, hair, and nails and helps our body detoxify.

In this article, you will find out why selenium is so necessary for our body, what a selenium deficiency can look like and how you can cover your daily requirements without any problems.

What is Selenium?

Selenium is an antioxidant and is responsible for several functions in our body. On the one hand, selenium is a component of the enzyme glutathione peroxidase, and, on the other hand, it provides essential trace elements and minerals. These help the body to detoxify and thereby ensure a healthy body function. The enzyme glutathione peroxidase protects our cells from oxidative stress and thus from external damage.

Selenium Functions and Effects  

Selenium is found in animal and plant foods and is also produced by the human body. This essential trace element is responsible for many functions in our body and supports several areas of our health: 

  • helps our body to protect our cells from free radicals and thus strengthens our immune system;
  • prevent cell mutations by cancer cells, which can correspondingly defend us from some cancers;
  • reduces the risk of stroke or heart attack;
  • protects our tissue and keeps us young.
  • together with iodine, helps to boost the metabolism and supports the thyroid gland;
  • binds heavy metals and thus expel them from our bodies;
  • stabilizes and strengthens our body cells.

Another important function of selenium - especially in combination with zinc and biotin - is strengthening and maintaining our nails and hair.

Selenium Daily Requirements

A selenium deficiency is rare and only occurs in people who have problems absorbing this trace element, such as people with chronic intestinal problems.

The Recommended Dietary Allowance (RDA) for adult men and women 19+ years of age is 55 µg daily. Pregnant and lactating women need about 60 and 70 µg daily, respectively.

This is how you can cover your daily selenium requirement with natural foods:

Food

Micrograms

(mcg) per

serving

Percent

DV*

Brazil nuts, 1 ounce (6–8 nuts)

544

989

Tuna, yellowfin, cooked, dry heat, 3 ounces

92

167

Halibut, cooked, dry heat, 3 ounces

47

85

Sardines, canned in oil, drained solids with bone, 3 ounces

45

82

Ham, roasted, 3 ounces

42

76

Shrimp, canned, 3 ounces

40

73

Macaroni, enriched, cooked, 1 cup

37

67

Beef steak, bottom round, roasted, 3 ounces

33

60

Turkey, boneless, roasted, 3 ounces

31

56

Beef liver, pan fried, 3 ounces

28

51

Chicken, light meat, roasted, 3 ounces

22

40

Cottage cheese, 1% milkfat, 1 cup

20

36

Rice, brown, long-grain, cooked, 1 cup

19

35

Beef, ground, 25% fat, broiled, 3 ounces

18

33

Egg, hard-boiled, 1 large

15

27

Bread, whole-wheat, 1 slice

13

24

Baked beans, canned, plain or vegetarian, 1 cup

13

24

Oatmeal, regular and quick, unenriched, cooked with water, 1 cup

13

24

Milk, 1% fat, 1 cup

8

15

Yogurt, plain, low fat, 1 cup

8

15

Lentils, boiled, 1 cup

6

11

Bread, white, 1 slice

6

11

Spinach, frozen, boiled, ½ cup

5

9

Spaghetti sauce, marinara, 1 cup

4

7

Cashew nuts, dry roasted, 1 ounce

3

5

Corn flakes, 1 cup

2

4

Green peas, frozen, boiled, ½ cup

1

2

Bananas, sliced, ½ cup

1

2


Source: U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, 2019.

* Since the selenium content in food can vary greatly depending on the growing area, information on the selenium content is limited in its informative value.

What Products Contain Selenium?

Our foods contain plenty of selenium. Excellent sources of selenium are meat, eggs, fish, asparagus, legumes, lentils, nuts, and Brazil nuts (caution: do not eat too many of these as they are contaminated with radioactive radium), collard greens, bulb vegetables, brown rice, and millet.

The selenium content in food depends on the selenium content in the soil. Due to climate change and changes in external environmental influences, the selenium content in our soil has been reduced. On the other hand, heavy metals are increasingly found in the ground. In Europe, the selenium content in plant-based foods is therefore relatively low. In the US, on the other hand, the soils are more affluent in selenium and supply their plant foods more than we do. The animal feed may be supplemented externally with selenium, which means that animal foods such as meat contain more selenium than plants.

Selenium Deficiency Symptoms

As already mentioned, a selenium deficiency is relatively rare. Nevertheless, it can have substantial consequences, which we want to take up briefly here.

A selenium deficiency can, for example, lead to thin and brittle hair or white spots on the nail surface. The immune system is weakened, and thyroid function can be impaired. It can also harm male fertility by reducing sperm production. Other deficiency symptoms can be headaches, joint pain, sleep disorders, or a general increase in the risk of infection.

Conclusion: Selenium Dietary Supplements

Here is a summary of all the essential information about selenium for you at a glance:

  • Selenium secures our entire immune system and protects us from hostile attackers who want to destroy our cells. At the same time, selenium, together with zinc and biotin, strengthens our hair and nails.
  • Since there could be a selenium deficiency in our society, it is advisable to supplement selenium with dietary supplements if you need it. Your family doctor can determine the selenium level in the body with a simple blood test. It then also gives instructions on the quantities in which selenium should ideally be supplied.
  • A balanced, colorful, and healthy diet is the be-all and end-all, but we can significantly improve our health with the supply of selenium. We strengthen our hair and skin, protect the immune system and strengthen our cells, prevent fatigue and headaches and support our cells in fighting free radicals.
  • However, too much selenium should not be supplemented, as this could have adverse effects.

Sources:

  • https://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/
  • https://www.hsph.harvard.edu/nutritionsource/selenium/
  • https://www.healthline.com/health/selenium-deficiency
  • https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6480557/
  • https://www.medicalnewstoday.com/articles/287842

Disclaimer: This article is a collaborative effort of the CLAV editorial team, created on the current literature base. All our publications are supplemented with passion and expertise for naturopathy and a healthy lifestyle. Our medical experts approve all texts before publication. Please Note: Dietary supplements are no substitute for a balanced, healthy diet or medical advice.

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