Ascorbic acid is the main cure for this disease (6)
I believe the answer is:
scurvy
(Other definitions for scurvy that I've seen before include "Sailors' old disease" , "(Of knaves) despicable" , "Lime-juice prevented it" , "Disease from lack of vitamin C - or dishonourable as knave may be" , "Disease once associated with poorly-nourished sailors" .)