Sweetener for tabloid America backed (5)
I believe the answer is:
sugar
'sweetener' is the definition.
(sugar is a kind of sweetener)
'tabloid america backed' is the wordplay.
'tabloid' becomes 'rag' ('rag' can be a synonym of 'tabloid').
'america' becomes 'us' (abbreviation for the United States).
'backed' says the letters should be written in reverse.
'rag'+'us'='ragus'
'ragus' reversed gives 'SUGAR'.
'for' acts as a link.
(Other definitions for sugar that I've seen before include "White or brown sweetener" , "e.g. Glucose" , "See 11" , "Cane or beet sweet stuff" , "Cane or beet product" .)