Vitamin could be a bonus not something that you always need. =)
i think in a pirate game, we don't search to survive (eat and drink), just want to hide or discover treasure, fight other boats and have fun ! ^^
So eating meat give you more strenght, vitamin speed or stamina, etc. And drinking water give you fortitude, beer more stronger but less clear-cut, etc.
Devs, make the experience better please, we don't want to waste our time to survive and we want to fight ! =D and discover things =)