I can’t remember learning in medical school anything about selenium[I knew about it from chemistry lessons]
Anyhow about 1965, I think I read the first time about it in a medical journal [letter to the editor] from a doctor who described how he treated successfully parents with Osgood Schlatter problems [young boys with pain in the lower leg[around the tuberosity of the tibia[ who has to stop doing sport/gymnastics because of pain.
He treated them with selenium and some vitamin E. This so much impressed me that I never forgot it and treated a patient this way during the years now and then. When I started working with complementary medicine in Israel, I learned a lot about t selenium.
Selenium has many medical applications; below, you can read some of the stories of selenium shortage in China and about the serious heart problems this causeds[cardiomyopathy] [Keshan disease]
Selenium has become more known with doctors in Israel since Corona but is not as known as zinc. It has been found that there is a strong relationship between various cancers and low selenium intake. One of the richest sources of selenium is Brazil nuts!
Selenium is extremely important for a good working thyroid, but for the moment, I want to mention one more indication which is extremely difficult to treat5: Lymphedema [for example, after breast cancer surgery ], where selenium seems to be very helpful even in oral form as capsules[it has also been given as intravenous]
Another time more about Selenium.