I have seven letters and am something you eat. My only anagram can help your pain. If you remove my first 2 letters I wear things down. Removing my first 3 letters is an adjective and removing my first 4 letters leaves a measure of time.
What am I?
Sausage. You eat sausage, assuage is the only single-word anagram and provides relief from pain. Usage wears things down, sage is an adjective and age is a measure of time.