The Importance of Getting Adequate Selenium Levels

The Importance of Getting Adequate Selenium Levels

When you don’t have enough mineral or you have too much of it in your body, your health suffers.

When you have the right quantity of selenium from your diet, you can have a strong immune system and decreased risk of death. But if you get more than the necessary quantity of selenium, you may have issues with type 2 diabetes, some types of cancer and hair loss.

Margaret Rayman, who is a Nutritional Medicine professor at the University of Surrey, England, said that there is a particular level of selenium that the body should have to maintain optimum health. Taking a bit more of selenium from a very low level results in improved health. But going beyond a certain level of selenium can be toxic to health and the effects will be visible.

What is Selenium?

Many food items contain the mineral selenium. Generally, selenium comes from plants and its quantity depends a lot on the selenium content of the soil where they are grown. Aside from plants, animals may also be a source of selenium if they eat plants containing selenium. Foods that are good sources of selenium are Brazil nuts, wheat, fish and poultry. Selenium supplements are also available in the market.

Countries that have high consumption of selenium are Canada, Venezuela, Japan and the United States. Europe and some parts of China have low consumption of selenium.

The recommended daily intake of selenium for men is 60 micrograms a day and for women it is 53 micrograms a day.

Varying Selenium Intake

Rayman reviewed the available medical literature for studies on selenium. He found that in different countries, the selenium daily intake varies ranging from a low 7 micrograms a day to a high 4,990 micrograms a day. European’s daily average intake is 40 micrograms. American women’s daily average intake is 93 micrograms while men’s daily intake average is 134 micrograms. The varying selenium intake of the different population is likely affected as well by the availability of selenium supplements. In the United States, this is quite significant with approximately half of the population taking dietary supplements or multivitamins with selenium.

The Risk of Low Selenium Intake


There are several studies that link low selenium levels to a higher risk of cancer deaths and deaths from other causes.

Weak Immune System

There are studies that show the importance of selenium to the function of the immune system. Rayman pointed out the role of selenium supplementation on the reduction of people being admitted to hospitals due to HIV infection.

Worsening Brain Function

Proper brain function requires selenium. A study involving adults who are 65 years old or older and had low levels of selenium showed worsening coordination performance, increased cases of Parkinson’s disease and increased risk of dementia.

If low selenium levels increase the risk of mortality, poor immune function and cognitive decline, then increasing selenium levels can most likely help reverse these problems. It would be possible to fight viruses, increase the success rate of male and female reproduction, lower the autoimmune thyroid disease risk and perhaps lower the risk of cancer.

The Risk of High Selenium Intake

Now, increasing the levels of selenium also comes with a risk. Rayman mentions the higher risk of having type 2 diabetes, hair loss, non-melanoma skin cancer and skin rashes for people with the highest selenium levels.

Duffy Mackay of the Council for Responsible Nutrition states that it is an established fact that adequate selenium intake has some health benefits, but there are some evidences showing that too much of selenium also carries a risk.

Mackay mentioned that it is likely that Americans have normal to higher selenium levels because of taking supplements. This does not mean, however, that taking supplements should be stopped.

The key is to get adequate levels of selenium. So, how do you know you’re not getting too much or too little of this mineral? The answer is to take a blood test to know your selenium levels.

If you don’t want to have a blood test, it is all right to say that you most likely don’t need more selenium if you’re living in North America. But this advice may not hold true in Europe.

There is no reason to worry that people will get higher than normal levels of selenium through diet. This may only be a concern if you’re consuming a lot of Brazil nuts frequently.

Photo credits: Brazil nuts by Jean Marconi via Flickr, CC by 2.0

Categories: Nutrition
Tags: selenium

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