Selenium along with vitamin E is important antioxidant which means it protects animal tissues from the oxidative damage caused by reactive oxygen species (ROS), actively formed during the normal functioning of cells. Production of such ROS depends on activity of the cells; more active the cell, more ROS will be produced. There is a dire need to clear such compounds from the body because they damage tissues. Due to antioxidant properties of vitamin E and selenium, they are important part of cells, which are very busy in metabolic processes like immune cells, which are basically white blood cells. There are two types of immunity. One is specific, which means a specific reaction is started in the body against a specific pathogenic invader. This type of immunity is for only one specific pathogen and does not protect against others. On the other hand, there is a second type of immune system, which is a general defence system. This means it protects all types of invaders. This is quicker and nonspecific and deals with all pathogenic invaders coming to body. It is observed in many studies that selenium deficiency alone or along with vitamin E deficiency impairs both types of immune responses.
