In Great Britain, sailors were given limes to eat - when aboard long-distance sailing vessels. Thus, they were called "Limeys". The vitamin C in limes prevented scurvy - as this is a disease which results from vitamin C deficiency.
Nowadays, just eating some citrus fruits and/or taking vitamin C supplements prevent scurvy from occurring.
Scurvy is very rare - in the United States, today. It does occur, however, in less developed parts of the world, especially in Africa.