Selenium is an essential trace element that supports an array of selenoproteins and selenium-dependent enzymes that are important for human health and well-being. One of these enzymes is glutathione peroxidase (GSH-Px), which has several important functions in the body. In addition, selenium supports a normal thyroid function. The thyroid function is important for keeping the metabolic rate in balance. Furthermore, selenium supports biological processes such as:

⦁        a normal immune system
⦁        production of normal sperm cells
⦁        cell protection
⦁        the maintenance of normal hair and nails

Most of the selenium in the body is found in two forms:
Selenomethionine (that is embedded in different proteins instead of methionine) and selenocysteine.
We only get selenomethionine from the diet because the body is unable to synthesize it. However, the body is able to convert selenomethionine into selenocysteine, which we are also able to get from the diet in the form of se-methylselenocysteine.
In situations where we get too little dietary selenium, the body uses stored selenium by converting the selenomethionine that is bound in different proteins.

SelenoPrecise contains both of these main selenium sources (selenomethionine and selenocysteine) plus several other selenium compounds.
 
The ability of selenium to bind to heavy metals
In the body, selenium binds to different heavy metals and forms insoluble compounds that are eventually discharged from the body. This process consumes some of the available selenium, leaving less for other important selenium-dependent processes*. Studies show that selenium binds mercury in a 1:1 ratio. When mercury and selenium bind, they form a chemically inert compound called mercury selenide, which is harmless to the body. However, the selenium that reacts with mercury is no longer available to selenoproteins that depend on the trace element. Insufficient selenoprotein synthesis can have a number of negative effects.
* Schrauzer GN Selenium and selenium-antagonistic elements in nutritional cancer prevention. Crit Rev Biotechnol. 2009;29(1):10-7.
 

What foods contain selenium?
Selenium is found in such things as fish, nuts, and whole-grain. People who do not consume these food items regularly may benefit from taking a selenium supplement to be on the safe side. The recommended daily allowance (RDA) for selenium is around 50-70 μg (it differs from country to country). Men generally need a little more selenium than women do.
 
Organically bound selenium has higher absorption
The selenium in the agricultural soil is inorganic. Once it gets absorbed by plants and ends up in animals who feed off the crops, it is converted into organic selenium. The selenium we get from our diet can be bound to amino acids such as methionine and cysteine. In contrast, selenium in supplements can either be organic or inorganic. It is known that organic selenium compounds are easier for the body to absorb and incorporate in the different selenium-dependent enzymes and selenoproteins.

The selenium content in agricultural soil differs
In countries where the agricultural soil is rich in selenium the population has a correspondingly high selenium intake. In the United States where there is a high selenium content in the soil (especially in the northern regions), the average selenium intake is around 60-220 μg daily.
As shown on the illustration, many European populations have low dietary selenium intake. The reason why the figures for Finland are not very low is that the country adds selenium to its agricultural fertilizers.

Selenium is many things
Selenium is a trace element and a mineral that is found in the soil in varying amounts. A country like the United States has a fairly high selenium content in the soil, while it is relatively low in most European countries. Grain and other plants absorb selenium from the soil. Therefore, the diet's selenium content depends on the amount of selenium in the agricultural soil.

Organic and inorganic selenium
It is important to pay attention to the different types of selenium when choosing supplements.

Inorganic selenium
In selenium supplements, inorganic selenium is often used in the form of simple selenium salts such as sodium selenite or sodium selenate. Selenium is usually insoluble in water, but selenium in the form of selenite and selenate is water-soluble. A little over 50% of these two inorganic selenium salts is absorbed in the body (selenite has slightly better absorption than selenate). However, they are excreted relatively quickly which limits their usefulness.

Organic selenium
Plants absorb inorganic selenium from the soil in the form of selenate. When the selenium is then incorporated into the plants as selenomethionine and, to a lesser extent, selenocysteine, it becomes organic selenium. The organic selenium compound L-selenomethionine - i.e., selenium attached to the amino acid methionine - can also be manufactured synthetically. Synthetic L-selenomethionine is widely used as an organic cell supplement and is one of the most thoroughly studied selenium compounds.
The selenium we get from animal food sources is primarily in the form of selenocysteine.

Selenium yeast
Selenium yeast originates from yeast cells that are grown in a selenium-containing nutrient substrate. It provides a high content of naturally occurring organic L-selenomethionine. The selenium yeast also contains methylselenocysteine as well as a variety of other organic selenium compounds that emulate the natural selenium variety that you get from a balanced diet. According to scientific studies, this broad scope of different selenium types is important. Before the selenium yeast is made into tablets it is inactivated by heat and turned into a powder, from which point it functions as a selenium- and protein-rich nutrient.

Selenium yeast differs in quality
There is also a difference between the quality of different yeast products. A non-standardized yeast is typically exposed to relatively large variations in the composition and amount of various selenium compounds. This also means that the absorbability of the selenium yeast can vary a lot. The yeast products with the best properties have pharmaceutical-grade quality with very tiny deviations in the composition and amount of different selenium compounds. Most importantly, these deviations are guaranteed to be within very narrow and predefined limits.