You may get 100% of those particular nutrients, but not in a natural form, and not with the synergistic elements (some of which may not even have been identified yet) that they come with in foods.
Get the bulk of your nutrients from real foods (ie: not processed cereals, or "enriched" foods--with some exceptions to make sure that you are getting the nutrients that your diet may be low in, like B12 for vegans like me, or calcium for many people). Think of these enriched cereals as another form of a multivitamin and don't overdo!
Be careful not to get excess amounts in particular of vitamin D, Iron, or vitamin A (which in non-food sources is usually not beta-or alpha- carotene--the second of which was more recently discovered it seems--but retinol palmitate, which can lead to problems. Beta- and alpha-carotenes are the form vitamin A comes in through foods, and supposedly you can not overdoes on these, because the body just converts the amount it needs). If you eat a vitamin enriched cereal, take a meal replacement drink with vitamins and minerals on, AND take a multivitamin, you could easily take too much of certain nutrients.
I've read of experiments done where rats :-( are fed a diet that contains all the nutrients known to man, in the form of supplements, with sufficient calories and protein. They died! There is obviously something in real foods (or many "somethings") that a lab just cannot duplicate.
I've just recently been noticing some foods (real foods!) as containig beta-carotene and alpha-carotene. The second is something I've only seen in the last few months. I believe it's because it was just recently isolated, and not previously identified. If I'm wrong, somebody educate me!
