Actually, there are some absorption problems with some of the minerals. Calcium is only absorbed in the presence of magnesium and activated vitamin D (not the vitamin D you get in the multivitamin: vitamin D that has already been processed twice in your body, by the liver and the kidney). Iron is only absorbed if it is in the Fe++ state and not the Fe+++ state (rust); therefore, it absorbs better in the presence of acid.
The best clue I have ever been given was from a nutritionist doc who told me to take the vitamin with the sort of food it’s normally found in. If you have a shot at absorbing the contents of the vitamin, rather than turning it into expensive feces, it’s best in the company of the sort of food you would expect to absorb the vitamin from. This was one of those “Duh!” moments that had me thumping my head. Those delicately specific transmitters in the intestinal lining cell membranes are tuned to pick up the vitamins and minerals in the presence of the sorts of food your ancestors got them from. Well, duh…
For which reason, not to disagree with Dr. Paprkia, you may well have a better shot at absorbing A, D, E, and K in the presence of fat. But very little fat is required: that’s why vitamin K supplements are enclosed in a couple of cc of vegetable oil. If I were having cereal with milk with my multivitamin in the morning, and I was particularly concerned with absorbing the calcium, I would make sure it was 1% milk and not nonfat. Unless I also had a piece of toast with a pat of butter. Don’t need much to have enough.
The problem with A, D, E, and K is that it is possible to absorb too much of them, whereas if you overdo it on C or B vitamins, you’ll piss them away. Nevertheless, you can get your body used to way-overdoing it levels of water-soluble vitamins. I remember reading a paper years ago (sorry, no cite) about an experiment feeding young men major megadoses of vitamin C for six weeks (part of the investigation into vitamin C and colds that followed Linus Pauling’s hysteria). By major megadoses I mean several grams a day. When the experiment stopped and they quit cold turkey, several of them promptly came down with scurvy. Fortunately the experimenters kept an eye on them and were able to prescribe a few grams a day of vitamin C, backing it down slowly to one gram and then half a gram and then no grams, and to report this unforeseen consequence in their paper.
All this begs the question of whether you really need the multivitamin. Your ancestors got by fine without it, and they produced you. If we really needed multivitamin supplementation to survive, we wouldn’t be here.