Is one multivitin a day enough?

This depends on a number of factors, including gender, activity level, dietary habits, and health status. Believe it or not, regular multivitamin consumption has never been proven to be beneficial for long-term health. It has also never been proven harmful. The idea behind a multivitamin—or MVI, in nutrition parlance—is that it incorporates the majority of vitamins and minerals in a single, convenient, relatively inexpensive pill. Most MVIs contain 50 to 150 percent of the Daily Value (formerly known as the RDI or recommended daily intake) of all vitamins.

For the average 35-year-old active male, I would recommend taking a daily multivitamin as backup. That will deliver all the vitamins and minerals that are hard to obtain without a balanced diet loaded with fruits and vegetables—which most of us, sadly, are not getting.

As for other supplements, endurance athletes who eat little to no red meat might consider a multivitamin with iron. And anyone with a family history of heart disease or who doesn’t regularly exercise should add a fish oil supplement for its heart-protective effects.