1. Oatmeal

Fueling the brain with breakfast is important for thinking, acting and learning. Children who are undernourished perform poorly on cognitive tasks. Not just any breakfast will do: research shows that fueling your kids with slower-burning carbohydrates (also called low-glycemic-index foods) like oatmeal instead of faster-burning, or high-glycemic-index, breakfast foods (think: sugary cereals) helps them to maintain their concentration and attention. 

Try these food solutions too: Bran cereals or whole-wheat bagels. Or send your kid off to school with this grab-and-go breakfast: Apricot-Walnut Cereal Bars.

2. Beans

New studies show that being even mildly iron-deficient affects learning, memory and attention. (About 10 percent of young women are anemic—because of their monthly loss of iron-rich blood.) Luckily, restoring iron levels to normal also restores cognitive function.

Try these food solutions too: Dark leafy greens, meat, poultry, fish or soy.

3. Yogurt

During childhood and adolescence, the body uses calcium to build strong bones—a process that's all but complete by the end of the teen years. Giving your kids enough calcium at a young age will help them to prevent osteoporosis later on. Yet more than 85 percent of girls and 60 percent of boys aged 9 to 18 fail to get the recommended 1,300 milligrams of calcium per day (kids aged 4 to 8 years old need 800 mg; toddlers aged 1 to 2 years need 500 mg). The 2005 Dietary Guidelines recommend 2 cups of low-fat or nonfat milk or dairy products per day for children 2 to 8 years old and 3 cups for children 9 years and older.

Try these food solutions too: Low-fat milk or low-fat cottage cheese.