If you already eat a nutritious diet, you may not need a supplement

While it’s true that a majority of Americans don’t get all of the vitamins and minerals needed through food, if you do eat a nutritious, balanced diet comprised mostly of whole foods, you most likely won’t gain any benefits from supplementation. “A healthy diet still seems superior to taking a multivitamin, and if you already eat a healthy diet, there may be less overall benefit from taking the extra vitamins,” Kormos said.
“If people ask me if they should take a multivitamin, I usually ask, 'Why do you think you need one?' They say, 'Well, I don’t eat this, I don’t eat that.' But a multivitamin is not going to replace the things missing from your diet. Whatever money you are spending on your multivitamin, it’s probably better to spend it at the farmer’s market or the grocery store on healthy foods.”