According to WebMD, The health ‘benefits’ of multivitamins might just all be a trick of the mind, researchers say. U.S. adults who regularly take multivitamins self-reported 30% better overall health than people who don’t use the supplements, results of a federally funded survey show. However, a comprehensive medical history — assessing dozens of physical and mental illnesses — revealed zero actual health differences between people who did or did not take multivitamins.