Supply of food providing assistance (7)
I believe the answer is:
helping
'assistance' is the definition.
(synonyms)
'supply of food' is the wordplay.
'supply' becomes 'help' (helping is a kind of supplying).
'of food' becomes 'ing' (I can't explain this - if you can you should give a lot more credence to this answer).
'help'+'ing'='HELPING'
'providing' acts as a link.
Can you help me to learn more?
(Other definitions for helping that I've seen before include "Food portion" , "Assisting" , "Serving" , "Portion; giving aid" , "Giving assistance" .)