BEthan
if you just want to know what vitamins and nutrients are found where and what their function is, you would do just as well to look up a GCSE biology textbook or even a revision guide.
If you want to find what is "healthy" to eat, you need to search the inernet for different theories of nutrition. I believe in the paleo diet myself, but there are lots of other theories. I can also recommend a book. "The Diet Deception", by Gary Taubes. It uncovers much of the rubbish that's been said about healthy balanced diets over the years.
Hana