Selenium is a strong antioxidant, reducing DNA damage and boosting immune system. It is believed to have some anti-cancer properties. It keeps cardiovascular health in check and boosts brain and memory performance. Lack of selenium can support development of certain diseases like Alzheimer’s. Selenium plays a role in proper function of thyroid gland, which contains highest levels of this mineral in our body. Thyroid gland and its function make sure to keep metabolism and proper development in order. Selenium also benefits skin health and can slow down ageing. Good sources include nuts, seafood, meat, as well as some mushrooms like shiitake.