Selenium plays a key role in metabolism. Selenium is an essential trace element that plays a key role in helping the immune system and preventing damage to cells and tissue .
In some countries, the UK included, selenium levels in the soil are very low. Plants get selenium from the soil, and so the levels of selenium available in the soil will affect how much is available in plant-based foods . Brazil nuts are a brilliant source of selenium. Just one a day can provide all your needs , or you can make sure you get some via a supplement.