2. Grade your child's diet.
Once you've pinpointed the target amount, try to determine whether your child's intake is in the ballpark. The best way: Record all the meals, snacks, and drinks your child consumes on two weekdays and Saturday or Sunday; note the portion size too.
Then go to the University of Illinois Urbana-Champaign Web site at www.nat.uiuc.edu, where you can plug in the foods and portion sizes for each day. The site analyzes your child's diet and gives you a chart noting each day's total calories, protein, carbs, fat, and essential nutrients compared to the recommended amounts for a child of that gender and age. Average the results of the three days. Don't sweat it if your child misses 100% of all the nutrients on one day -- it's the average that counts.
If the program fails to detect a shortfall of any nutrient, your child doesn't need a vitamin supplement. "While giving a healthy eater a children's supplement wouldn't result in an overdose of nutrients -- even iron -- it's not necessary," says Dr. Picciano. Plus, some nutrients work best in a narrow range close to the RDA. For instance, a bit too little or too much zinc wears down the immune system. If the program identifies a problem, however, highlight the nutrients in question and move on to the next step.
3. Fill in nutrient gaps.
You'll have an easy time correcting a shortage in one or two nutrients. Suppose your 6-year-old meets 75% of her calcium needs. By substituting a cup of milk or calcium-fortified o.j. for a cup of soda, fruit punch, or juice, she'll exceed her calcium needs. Is iron the issue? Trade a jelly-topped bagel for a tuna sandwich or add chicken to pasta and her iron intake will rise by at least one-third. To find food sources for specific nutrients, go to www.nutrition.org/nutinfo.
But if your child is deficient in many nutrients, one or two switches are unlikely to fix the problem -- and he'll probably balk if you make sweeping changes at once. So how should you begin? Rethink the snacks you offer, suggests Elizabeth Ward, R.D., Reading, MA-based author of Healthy Foods, Healthy Kids. For instance, if your child noshes on potato chips and fruit punch, switch to trail mix and a fruit smoothie made with milk to considerably up her intake of calcium, vitamin C, and B vitamins. If she usually munches on cookies or cupcakes, replace them with banana bread (loaded with potassium), carrot cake made with whole wheat flour, or pumpkin muffins (both rich in vitamin A).