That said, if you are deficient in a certain vitamin (or are looking to supplement, not substitute your diet), there are ways to navigate the vitamin industry with intelligence and intention. First and foremost, any vitamin regimen should be always discussed with your medical provider to avoid potential drug interactions. Also, be mindful of dosages — according to Michos, there's no need to exceed the recommended daily value of anything. "[Ask yourself] why are you taking this? What is the purpose? What are you trying to treat or correct?," she says. "It’s important to note that high doses — too much of a good thing — can have side effects, so more is not necessarily better."