New rake can provide protein (7)
I believe the answer is:
keratin
'protein' is the definition.
(keratin is a kind of protein)
'new rake can' is the wordplay.
'new' is an anagram indicator.
'can' becomes 'tin' (both are metal containers).
'rake' anagrammed gives 'kera'.
'kera'+'tin'='KERATIN'
'provide' is the link.
(Other definitions for keratin that I've seen before include "Protein found in hair and nails" , "Hair, nails substance" , "Rate ink (anag) - fibrous protein" , "Material in hooves and nails" , "Constituent of hair/nails" .)