5 Important Nutrients for Families

Keep kids of all ages healthy and strong

Photo: Two young girls drinking glasses of milk

Parents have a lot to remember. Keeping show-and-tell dates and carpooling details straight are just the beginning. Specific nutrient needs for each age? That could be pushing it.

Fortunately, Jill Castle, RD, pediatric dietitian and co-author of Fearless Feeding, has you covered. “If you look at most nutrition books, they try to tell you about every nutrient under the sun, and it tends to be very overwhelming and hard for parents,” she says. “So what we’ve tried to do is keep it very simple so they can really do it.” Here, she identifies the five most important nutrients for every family by age group.
Infants: Birth to Age 1

Most important nutrient: Iron 

Why it’s essential: “The brain is where it’s at in infancy,” Castle says. She says infants need 11 milligrams (mg) of iron per day to support their rapid body and brain growth. “Iron is carried in every cell,” she says. “It transports oxygen to all the cells and is critical for brain growth.” 

Best sources: “Most babies meet their iron requirements with breast milk or infant formula,” she says. “But once you start transitioning around 4 to 6 months to feeding them solid foods, parents need to make sure that they’re introducing either an iron-fortified cereal source or strained meats.”

Toddlers and Preschoolers: Ages 2 to 5

Most important nutrient: Vitamin D

Why it’s essential: “Its major role is to help bones get hard,” Castle says. “You can drink all the calcium in the world, but if you don’t have vitamin D there with it, the absorption into the bone doesn’t happen properly.” She says toddlers need 600 IUs of vitamin D per day, but 1 cup of milk is only 100 IUs. “It’s one of those nutrients that you have to pay a little bit of attention to,” she says. “And toddlers are famous for not liking milk or not wanting to eat fish.” 

Best sources: “It’s really hard to find foods that are natural sources of vitamin D,” Castle says. Fish and vitamin D–fortified products like milk, orange juice, and eggs are good options. For these youngsters, presentation matters. She suggests calling salmon by the more appealing name “pink fish,” and serving tuna sandwiches or crackers topped with tuna. 

School-Age Kids: Ages 6 to 12

Most important nutrient: Potassium 

Why it’s essential: “Potassium does a ton of stuff,” Castle says. “It helps the muscles contract, maintains fluid and electrolyte balance in the body, helps the nerves do their thing. It’s pretty important, and we know kids aren’t getting enough.” She says the deficiency can be most attributed to low fruit and vegetable intake. Every day, 4- to 8-year-olds need 3,800 mg, and 9- to 13-year-olds need 4,500 mg.

Best sources: “Parents might be avoiding potato for their kids, because they think for themselves it’s a bad thing to eat,” Castle says. “But the truth is it’s a great source of potassium, and kids need potassium.” A small baked potato has about 750 mg.  Other good sources include low-fat yogurt, tomatoes, oranges, orange juice, and bananas.

Teenagers: Ages 13 to 18

Most important nutrient: Calcium

Why it’s essential: “For teens, I singled this one out because there’s that limited window when teens are able to deposit all that calcium and vitamin D and build up their bone status,” Castle says. “Between age 19 and the early 20s, they start to just lose bone mass—there’s no more building.” She says teenagers need about 1,300 mg of calcium a day, but most aren’t getting that much. 

Best sources: “They don’t have to love milk,” Castle says. “Teens like pizza and that has mozzarella cheese, which is a great source of calcium.” She recommends calcium-fortified dry cereals, which can contain up to 1,000 mg per 1/2 cup. Fortified orange juice and low-fat yogurt are other good options.
The Whole Family: All Ages

Most important nutrient: Fiber

Why it’s essential: “Fiber acts like a broom for your intestinal tract,” Castle says. “It brushes out the debris and in turn helps reduce our rates of colon cancer, other cancers, and heart disease.” It also keeps things running smoothly and helps prevent constipation, which is a common concern in toddlers, preschoolers, and young children. Fiber is filling and has staying power, which can help prevent overeating and childhood obesity. “Less than 3% of children 4 to 8 years old are getting enough fiber,” Castle says. And adults aren’t doing much better. Adult women need 28 grams (g) per day, and men need 35 g. For kids, Castle uses the Rule of 5: start with 5 g of fiber then add the age of the child. So, a 5-year-old needs 10 g, a 10-year-old needs 15 g, and so on. 

Best sources: Beans, lentils, bran, vegetables, pears, berries, apples, and almonds are all good sources.