“... supplementing the diet of well-nourished adults with (most) mineral or vitamin supplements has no clear benefit...”
This is a great example of how a precise statement by a researcher is misinterpreted or misrepresented when presented to the general public. The above statement is a useful result with a well-defined meaning which is being used in a context that makes it sound like supplements have zero benefit. It's no surprise that that supplements have no clear benefit... when you are a "well-nourished adult'! The danger is that this result can cause people who are not well-nourished to stop taking supplements that may be keeping them outside of harm.
Writers looking to make a story where there isn't one cause much more harm than supplements ever could. (No facts were harmed in the making of that statement.)