Avoid supplements that provide megadoses. In general, choose a multivitamin-mineral supplement that provides about 100 percent of the Daily Value (DV) of all the vitamins and minerals. Try to avoid those that, for example, have 500 percent of the DV for one vitamin and only 20 percent of the DV for another. The exception to this is calcium. You may notice that calcium-containing supplements don't provide 100 percent of the DV. If they did, the tablets would be too large to swallow.