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Children thrive on dozens of nutrients that work together to promote growth and development. While no single nutrient, or group of nutrients, is any more important to a child's well-being, these five come up a lot when the subject is kids' nutrition.
Calcium, the most abundant mineral in the body, maximizes bone growth and shores up the skeleton during childhood and beyond. A small but significant amount of calcium in the bloodstream is necessary for normal heart beat, blood clotting, and muscle function. The body "withdraws" the calcium it needs from bones to maintain blood levels, which is partly why children need adequate calcium every day. Many kids don't get enough for their nutritional needs.
"American kids are suffering from a calcium crisis," says Keith-Thomas Ayoob, EdD, RD, associate professor in the department of pediatrics at Albert Einstein College of Medicine in New York. "And it does not bode well for their bone health, now or in the future."
Teenage girls in particular are among those with the lowest calcium intake relative to their needs. Calcium deficiency is especially dicey during adolescence, when the body forms about half the bone mass it will ever have. Consistently coming up short for calcium during these years is one of the risk factors for bone-thinning osteoporosis decades later. It's even worse for females because of their greater risk for the condition.
How much calcium is enough? According the Institute of Medicine, the group that determines nutrient needs, kids' daily needs for calcium vary by age:
Ayoob says part of the solution to low calcium intake is offering young children and teens calcium-rich beverages and snacks rather than soft drinks, snack chips, and candy. Eight ounces of white or flavored milk, 8 ounces of yogurt, and 1.5 ounces of hard cheese each contain about 300 milligrams of calcium.
While dairy foods are concentrated calcium sources, calcium is also plentiful in plant products, such as fortified orange juice and soy beverages, tofu processed with calcium sulfate, and certain breakfast cereals (check the box label to be sure).
The benefits of making high-calcium foods, particularly dairy, part of your child's daily diet may extend beyond building strong bones. "Emerging research suggests the calcium in dairy foods as part of a balanced diet helps adults achieve and maintain a healthy weight, and the same may be true for children," according to Sheah Rarback, MS, RD, director of nutrition and associate professor at the Mailman Center for Child Development at the University of Miami.
Preliminary evidence shows dairy does work for kids. A Journal of the American Dietetic Association study linked higher calcium intake to lower body fat levels in children aged 2 to 8. Milk and dairy foods were the main sources of calcium in the children's diets in the study.
"Protein is part of every single body tissue," says Rarback, "so that gives you an idea of how important it is to children who are, by their very nature, growing nearly all the time."
Protein provides calories, but its amino acids are what the body really needs. Amino acids are the raw materials for building new cells and tissues and the compounds that direct bodily processes, including enzymes and hormones.
Protein is found in animal and plant foods, with a difference. Animal foods, particularly eggs, supply the amino acids, known as essential amino acids (EAA), that your child's body cannot make. No plant food supplies all of the amino acids, so vegans (those who eat no animal food products) must eat an array of protein-packed plant foods to get the EAA they need. Vegetarians who include dairy foods and eggs typically satisfy EAA needs as long as they eat enough.
Protein needs are highest on a pound-per-pound basis during infancy. They increase again just before adolescence as the body readies for another growth spurt. Kids' daily needs for protein:
"Protein is not a problem for most kids, even those who don't eat meat or don't eat it consistently," Ayoob says. For example, just 16 ounces of milk or yogurt, or 2 ounces of meat, chicken, or seafood, and an egg satisfy a 3-year-old's daily protein needs.
Kids need fiber for good nutrition and healthy growth. But fiber is an oddity among carbohydrates. It's a complex carbohydrate minus the calories. Your child can't digest dietary fiber to get at the energy it provides, so what's so good about it?
"Kids need fiber for the same reasons adults do," says Rarback. "And like their elders, children get way less fiber than they need."
Rarback says studies show fiber wards off type 2 diabetes and elevated blood cholesterol levels in adults, and, possibly, in children. Fiber's confirmed benefits for kids include fending off constipation and promoting fullness. High-fiber foods, including whole grains, legumes, fruits, and vegetables, keep kids fuller for longer, a boon in the battle of the bulge. And fiber-filled foods are rich in vitamins and minerals.
To figure fiber for kids, Rarback uses the method endorsed by the American Academy of Pediatrics, and you can, too. Simply add five to your child's age to determine daily fiber needs in grams. So, a 13-year-old needs about 18 grams a day.
Having a number in mind helps with reading food labels, but it's not necessary to track every gram of fiber your child eats. "Instead, make whole grains, fruits, and vegetables available to your child every day, and consider adding legumes to your family's meals to get the fiber your child needs," recommends Rarback.
Antioxidant nutrients, including vitamins C and E, beta-carotene, and the mineral selenium, receive a lot of attention for their potential to head off chronic conditions in adults, including cancerand heart disease. While their effects are still under study, experts regard antioxidants as the "superheroes" of nutrients.
Antioxidants battle the effects of free radicals. Free radicals are by-products of normal metabolism that also form when you're exposed to air pollution, cigarette smoke, and strong sunlight. As free radicals accumulate, they can damage DNA, the genetic blueprint for cell reproduction, as well as other cell parts.
"Antioxidants may give your child's immune system a boost," Ayoob says. "Since they're not available in pills, kids need food for antioxidants."
While there's no research to back up the effects of antioxidants on a child's well-being, Ayoob and Rarback agree that you can't go wrong by offering children antioxidant-rich foods, such as whole grains and produce.
Brightly colored fruits and vegetables, including blueberries and other berries, broccoli, spinach, tomatoes, sweet potatoes, cantaloupe, cherries, and carrots are among the produce offering the most antioxidants.
Your child depends on iron to grow. Red blood cells need iron to ferry oxygen to every cell in the body. Iron also plays a role in brain development and function.
"Iron is so critical to brain development that the negative effects of a daily iron deficiency on cognition may be irreversible, even when the shortfall is small," Rarback says.
According to the American Academy of Pediatrics, iron deficiency is the most common nutritional deficiency in America, affecting mostly older infants, young children, and women in the childbearing years. Small children are at risk because they grow so fast. Teenage girls and women must make up for monthly blood losses with iron-rich foods or dietary supplements. An iron deficiency can lead to anemia, which often saps a child's energy.
Both animal and plant foods provide iron. Animal products, such as meat, dark meat poultry, and seafood, supply heme iron, the form of iron the body absorbs the best. Plant foods, including spinach and legumes, supply nonheme iron. Nonheme iron is also the type of iron added to breads, cereals, pasta, rice, and fortified grains.
A steady supply of fortified grains can provide enough iron, even for those who don't eat meat and who should take a daily multivitamin with iron for safety's sake.
Also, "you can boost nonheme iron absorption by adding a source of vitamin C," says Ayoob. "Offer kids foods such as oranges, orange juice, tomatoes, kiwi, strawberries, or red bell pepper with each meal to make the most of nonheme iron."