The Alterrans achieved immortality through their rejuvenation chambers. However, when they were damaged, En.Ki developed a Tree of Life -- its nourishing fruit cured most illness and prolonged life.

Immortality, the Elixir of Life and the Food of the Gods

www.ancient-origins.net

When we look into the accounts of many different mythologies and religions, it becomes clear that the gods are either immortal or live a life of many thousands of years.  What is rarely mentioned