Lets talk about basic functions of Vitamins:

Vitamin A is the defender of the body making white blood cells and well maintains our visions.
B Complex: To release the energy from food. Other B vitamins use that power for our body.
Vitamin C : To fight against the infections and from making collagen helping to make teeth, bones & to fix wounds.
Vitamin D is building calcium and phosphorus to make bones and
Vitamins E is antioxidants helps to Clear the elements from our body that could damage our cells.
Vitamin K composite proteins.