I recently read an article about combatting malnutrition with vitamins. It was about a program that was helping malnourished people in third world countries by supplying vitamins instead of food. They were able to help ALOT of people on relatively little money. The head of the program said that even with a poor amount of food intake, the effects of malnutrition were remarkably reduced / held off with vitamins. (The before/after photos were remarkable indeed.)

This makes me think that vitamins would be a must-have for a survival kit, to have on hand during times of trouble and a potential lack of food.
So stock up on vitamins as well as food.
Could really make a difference during extended periods of trouble.