Salad ingredient consumed by undergrad is healthy (6)
I believe the answer is:
radish
'salad ingredient' is the definition.
(radishes are often used in salads)
'consumed by undergrad is healthy' is the wordplay.
'consumed by' indicates a hidden word (I've seen this in other clues).
'RADISH' is hidden in the letters of 'undergrad is healthy'.
(Other definitions for radish that I've seen before include "Daikon or mooli" , "Bit of salad" , "Pungent fleshy edible root eaten in salads" , "Sir had this vegetable" , "3 down" .)