Amy,
The problem with vitamins is that they are isolated nutrition -- any excess just gets flushed out of your system soon after you take it. If you want to prevent illness, you need to boost your immune system, and that means more antioxidants (disease fighters in the body) that you get from fresh whole fruits and veggies. It can be really difficult to get enough of those, especially raw, which is when they provide the most nutrition and disease-fighting phytonutrients. I'm a distributor for a product called Juice Plus+ -- it's basically 17 servings of fruits, veggies and grains in capsule form (and if you wanted to give it to your daughter, it comes in chewables or gummies). It's whole food based nutrition, so you get all the good aspects of those foods, with phytonutrients that work together -- much better than one or a few vitamins alone. My personal experience, and why I started taking it myself, was after my first year as a teacher. I was sick 6 or 7 times that year, cold, flu, you name it. I started taking Juice Plus+ and my second year, I wasn't sick at all! That doesn't mean I never get sick, but I can see a big difference in the frequency and severity of any illnesses I do get. I'd be happy to get more info to you if you're interested. You can also check out my website and contact me from there -- http://www.juiceplus.com/+ah81530