An element of helpfulness in diet (4)
I believe the answer is:
iron
This could be a double definition.
'an element' is the first definition.
(iron is a kind of element)
'helpfulness in diet' is the second definition.
Both the definition and answer are adjectives. Perhaps they are linked in a way I don't understand?
'of' is the link.
Can you help me to learn more?
(Other definitions for iron that I've seen before include "Hard metal" , "Smooth - driver?" , "Metallic element, symbol Fe" , "Metal - press" , "sports club" .)