As a supplement selenium comes either in its inorganic (elemental) form, or as an organic compound attached to an amino acid.
Selenium is a trace mineral that we need to consume regularly to support, in particular, a healthy thyroid. Selenium also helps regulate blood pressure and cholesterol levels, and works as an antioxidant to support the immune system. Another role of selenium is reducing toxicity caused by heavy metals. Deficiency can affect healthy ovulation, male fertility and successful pregnancy. Deficiency can also lead to thyroid problems, such as hypothyroidism, abnormal weight gain and chronic fatigue.
Selenium deficiency in Kiwis
Selenium deficiency is relatively uncommon in many parts of the world, because it occurs naturally in the soil and is absorbed by the plants grown to produce food. However, selenium deficiency is a problem in New Zealand, because it is lacking in our soil. Some foods are fortified with selenium and other trace minerals, and some food producers have also attempted to introduce selenium to the soil.
Different types of selenium
Selenium is a chemical element (atom) that is also found in combination with amino acids, called ‘selenomethionine’ or ‘selenium methionine’ after the amino acid it is attached to: methionine. This form of selenium is the most readily absorbed by the human body, and is the form most common in brazil nuts, some fish and legumes. Other selenium-containing amino acids are selenocysteine and methylselenocysteine. Methylselenocysteine is the form most common in vegetables such as onions, broccoli, cauliflower and garlic. There are two forms of selenomethionine: L-selenomethionine and D-selenomethionine. L-selenomethionine is the one that is biologically significant.
There are also inorganic forms, selenite and selenite, as well as selenium-enriched yeast, which contains inorganic selenium that binds to the yeast proteins.
All forms of selenium are well absorbed, but especially selenomethionine. This is because it’s absorbed in place of methionine, an essential amino acid obtained from food, and this increases absorption efficiency compared to inorganic forms of selenium.
About Health’s Element 12 magnesium relaxation formula and our Multiva multivitamin both contain this form of selenium and are specially formulated for New Zealand men and women.
The main reasons for taking a health supplement containing L-selenomethionine are to support the thyroid, immune system and healthy cholesterol levels. Selenium is necessary for building selenoproteins, which are needed to activate the thyroid hormone, and several of which are also important antioxidants. Of course, like any essential nutrient, you can have too much of a good thing. The recommended daily intake for New Zealand adults is 60-75mcg/day.
Foods that contain selenium include brazil nuts, eggs, liver, tuna and poultry, as well as some grains, legumes and vegetables, but local New Zealand produce may contain less, because our soil lacks selenium.