Compare to the root part you usually eat, the leaf part has more than twice of vitamin A, third times of protein, five times of calcium, and etc.*
Don't throw it away...
I usually make furikake(sprinkle on rice) out of the leaves.
This is how:
1. cut the leaf part and wash well,and pick the leaves from the stem.
2. put the leaves on a parchment sheet and microwave it (about 3 min? It depends how much leaves you put on. Put the sheet 1 min and see how the leaves look like, put 1 min again, continue till the wetness of leaves is gone.)