Riboflavin
Why you need it: Riboflavin—yet another B vitamin—is an antioxidant that helps the body fight disease, create energy, and produce red blood cells.
Where to get it: At nearly 3 milligrams per 3-ounce serving, beef liver is the richest source of naturally occurring riboflavin. Not in the mood for liver? Luckily, fortified cereals (like Total or Kellogg’s All-Bran) provide nearly as much of the vitamin in a far more convenient (and palatable) package.