It's great to have access to all the nutrients you need in pill form. But when you eat healthfully and take a supplement, then you may be getting more than you need. Even if you're not the healthiest eater, experts say that our food is so fortified that there is concern about vitamin overload. Here are a few vitamins and nutrients to watch. Red, yellow and orange fruits and vegetables contain vitamin A, which promotes healthy teeth, bones, skin and vision. But too much A - more than 3,000 IU per day - can have the opposite effect, causing reduced bone density and hair loss. Pork loin, roast beef and baked potatoes are loaded with B vitamins, but high doses of B6 can cause nervous system damage. Folate - necessary for pregnant women and fetal development, plus healthy circulation - is found in many fortified foods, but it can cause nausea and other digestive issues in excess.