What vitamins are best for ensuring a teenager is healthy?

Whole Food Vitamins: Vitamins are widely available, and they are also widely VARIABLE in their quality. In general, vitamins made from whole foods (they will be labeled as such) are more easily absorbed and used by your body and are a better choice. These types of vitamins are generally only available at health food stores, both local and online. Opt for those labelled organic, and read dosing recommendations well.