Vitamins for Birds??

I have a question for the parrot owners who read this forum!

Do you give your bird vitamin supplements, in addition to seeds and table-foods? Do you buy pellets or regular seeds with the sunflower seed? I know that some bird owners say that allowing the bird to have sunflower seed is not healthy for parrots. Too much fat and cholesterol in the seeds. But, isn't the same true of food from the dinner table???

Do you really need to feed extra vitamins??? If you do, what brand and in what form (powder, etc.)???