We all leak tiny amounts of albumin (a protein which has a small molecular size and is water-soluble) into our urine. If the filters in our kidneys are damaged, increased amounts of albumin and other larger proteins from our blood can pass through and escape into the urine.
Definition of aftertaste. : persistence of a sensation (as of flavor or an emotion) after the stimulating agent or experience has gone.
Incidental means secondary in time or importance. If you lose weight because you moved and must walk further to school, the weight loss was incidental to the move. When something is incidental, it is never the main thing. It's okay to include incidental details as they can add depth to your storytelling, but they are never crucial to the story.