When discussing diet during a teen's checkup, I usually try to address the two things that can be lacking in a teen girl's diet -– calcium and iron.
Calcium is important for a teen girl to have because of her future risk of osteoporosis. Girls build bone from puberty until their late twenties, so inadequate calcium during this time puts them at future risk for brittle bones. Teen girls need 1300 mg a day but they often get much less than that. Great sources of calcium include fortified cereals, fortified soy milk, dairy products, certain fish (with bones), tofu, and leafy greens. Calcium needs vitamin D (400 IU a day) to be absorbed so sources of calcium that have vitamin D like fortified cereals are helpful. Additionally, getting enough time outside in the sunlight allows our bodies to make vitamin D –- another reason to encourage your teen to get up from the computer and get outside!
Dietary iron is also important for teen girls. Teen girls can sometimes develop iron-deficiency anemia, particularly after menstruation starts to happen more often. Teen girls need approximately 15 mg of iron a day to meet their needs. Good sources of iron include clams, fortified cereals, soybeans, beans, blackstrap molasses and various kinds of meat. Vitamin C can help with the absorption of iron, so eating high iron foods along with citrus and other vitamin C-containing foods is a good idea.
Cereal with milk (or soy milk) and a glass of orange juice, anyone?
America's Teen Girls Lack Calcium. National Women's Health Resource Center. April 27, 2009. http://www.healthywomen.org/resources/womenshealthinthenews/dbhealthnews/americasteengirlslackcalcium
Dietary Supplement Fact Sheet: Iron. National Institute of Health. April 27, 2009. http://ods.od.nih.gov/factsheets/iron.asp
U. S. Department of Health and Human Services. Dietary Guidelines for Americans 2005. April 27, 2009. http://www.health.gov/Dietaryguidelines/dga2005/document/html/AppendixB.htm