Selenium is a mineral we need in tiny amounts – only 55 micrograms a day, which is less than one 10,000th of a gram! Despite this, it’s still vital for our health, including for our thyroid and our metabolism,... Read more
Selenium is a mineral we need in tiny amounts – only 55 micrograms a day, which is less than one 10,000th of a gram! Despite this, it’s still vital for our health, including for our thyroid and our metabolism, for supporting our cells against free radical damage, and for making healthy sperm. The best food source of selenium is Brazil nuts, with other good sources including organ meats, fish and shellfish.
Primary functions of Selenium
How much selenium do we need?
The nutrient reference value for selenium in the UK is just 55 µg (micrograms) for adults. Nutrient reference values refer to the amount needed to ensure that the needs of nearly all the population (97.5%) are being met.
The best common food sources of selenium are:
Deficiency signs and symptoms*
Symptoms of selenium deficiency may include :
*If you experience any of these symptoms, please consult your doctor or health practitioner.
Forms and bioavailability / What to look for when buying a supplement
There are a few different forms of supplemental selenium on the market. These include:
As well as these differences in absorption, these various forms of selenium may have different benefits for the body. For example, it’s said that organic forms of selenium (such as selenomethionine and yeast-bound selenium) may be better for increasing blood levels of selenium, yet the inorganic forms (such as sodium selenite) may actually be better for increasing levels of the antioxidant enzyme glutathione peroxidase.
In summary, it seems that there may be advantages to all of these different types of selenium, and there is not one that particularly stands out as better than the others.
Dosages: Lifestyle Labs’ recommendations
Adults: Selenium supplements for adults typically provide between 100 and 200 µg of selenium per daily dose. In general, we don’t advise taking more than 200 µg in supplement form on a long-term basis (also see ‘Safety’ below) unless otherwise advised by your healthcare practitioner.
Children: Selenium is not generally given as an individual supplement to children, although those over 8 years can take half an adult dose – up to 100 µg a day. Multivitamin and mineral supplements for children under this age may contain up to around 50 µg a day. More than this may be recommended by a healthcare practitioner.
If you are taking any medications or have any medical condition, please consult your healthcare practitioner before taking selenium.
For most people, selenium is a very safe supplement to take at the advised levels. However, high doses of this mineral can be toxic. It’s not advisable to regularly consume more than 400 µg of selenium a day in total from food and supplements, and so we recommend no more than 200 µg in supplement form if taken on a long-term basis (unless otherwise advised by your healthcare practitioner). If you’re already taking a multivitamin and mineral supplement, check how much selenium it contains
If you are regularly eating several Brazil nuts a day, it can be best to avoid supplements containing selenium.