Are multivitamins worth it?
A multivitamin can be a reasonable backup when intake is limited, calories are low, food variety is poor, or a clinician recommends one. It is not a replacement for a nutritious diet.
Evidence does not support treating multivitamins as a general solution for cardiovascular disease or cancer prevention in otherwise well-nourished adults.
If you suspect a deficiency, testing and targeted replacement are often better than guessing with high doses.