Stardust or the elements in our bodies
The saying that you are referring to is from Carl Sagan, when he stated that:


  "We are a way for the universe to know itself. Some part of our being knows this is where we came from. We long to return. And we can, because the cosmos is also within us. We're made of star stuff," 


Quote source

In answer to your question, yes, we are 'repurposing' the elements that make us up, as are all living and non-living matter.

Chris Impey, professor of astronomy at the University of Arizona is quoted in the article Are We Really All Made of Stars? (Melina, 2010) as stating:


  the fact that the carbon, nitrogen and oxygen atoms in our bodies, as well as atoms of all other heavy elements, were created in previous generations of stars over 4.5 billion years ago. Because humans and every other animal as well as most of the matter on Earth contain these elements, we are literally made of star stuff


The elements that make up the cells etc in humans and any life forms, as with the materials that make up the Earth itself were ultimately formed by nucleosynthesis processes (mostly fusion and neutron capture) in stars, explained in the webpage Origin of the Chemical Elements as being:


  the early Universe consisted almost entirely of the element hydrogen, with a small amount of helium present too. Hydrogen, therefore, is thought to be the starting material from which all other elements have been built. This is consistent with the very high abundance of hydrogen in the solar abundance profile. The process may be thought of as a series of fusion reactions which weld together simple atomic nuclei to build increasing complex atomic nuclei.