That got Invisibilia co-host Lulu Miller wondering if anything about us stays the same. Do all the cells in our body turn over every seven years as is sometimes claimed, with new cells replacing old ones? Or is there something that we hang on to for life?
It turns out that each body part has its own very distinct lifespan. The lining of the stomach, constantly under assault by digestive acid, is renewed every few days.
But bones are refreshed once a decade. And there are a few parts of you that stay with you from birth to death.