I know CD contains 100% RDA of vitamins and minerals, but RDA is really the very MINIMUM amount your body needs (most people think is is the maximum). Probably wouldn't be a problem to take an extra supplement. Safe maximum levels are usually many, many times the RDA but of course it would be worth checking these first, especially fat soluble vitamins. As for the water soluble ones, no problem because what your body doesn't use it gets rid of.