Whether you’re a junk food junkie or a health nut, you may be wondering whether you’re getting enough essential vitamins and minerals. If your typical diet consists of fast food and supersized sodas, you probably have a hunch that you’re missing out on certain nutrients. But even if you’re eating a well-rounded diet full of fruits, vegetables, lean protein, whole grains and healthy fats, you still may be deficient in a few key vitamins and minerals. “There are certain nutrients that are hard to obtain through food, and some populations may need supplementation,” says Christine Gerbstadt, M.D., R.D., spokesperson for the American Dietetic Association based in Sarasota, Fla., and author of Doctor’s Detox Diet. “Almost anyone can benefit from more vitamin D, E and calcium, and women of childbearing age still don’t seem to be getting enough folic acid,” she notes. Keep reading to see which nutrients you can’t live without, which ones you may be lacking -- and the smartest, safest ways to get more of them.