I've been wondering about this for a while, since getting interested in knife sharpening.
When using a knife, it will get duller. One (the primary) reason being that you "bend" the edge. You fix this using a honing steel.
After a while though, you need to sharpen the knife again. Another setting: If you have a brittle knife and/or mistreat your knife you will chip it.
As far as I can tell, this should mean that small pieces of metal (dust, shavings, etc.) come lose, and then likely get in the food.
Is this correct? Are there no health considerations when digesting small pieces of very sharp metal?