Nutrient games

Growing children need a host of nutrients to grow and develop properly, including these two nutrient superstars:

• Vitamin D plays many roles in the body including regulating cell growth, bone development, calcium balance, and immune system function. Before the widespread fortification of milk with vitamin D, rickets was a common problem.
• Iron is equally important for children, as it aids in proper neurological development. Iron deficiency can cause anemia, as well as developmental delays and behavioral problems.

Have your vitamin D and iron, too

To see just how much milk it takes to boost vitamin D levels without lowering iron stores, Canadian researchers looked at 1,311 healthy children between 2 and 5 years old. Parents gave information about their children's milk consumption and bottle use, and the children's blood levels of vitamin D and iron stores were measured.

• Vitamin D levels increased and iron stores decreased as children drank more milk.
• Most children who drank 2 cups of milk per day maintained adequate vitamin D levels without depleting their iron stores.
• Children with darker skin pigmentation needed up to 4 cups of milk per day to get enough vitamin D.
• Bottle use did not raise vitamin D levels but led to dramatic decreases in iron stores.

Since 4 cups of cow's milk resulted in a larger decrease in iron stores, researchers point out "the importance of vitamin D supplementation during the winter among children with darker skin pigmentation to maintain vitamin D stores." They also noted that bottle use isn't helpful for improving iron or vitamin D status in children, possibly because whatever is in the bottle might be replacing other foods and drinks in the diet containing these nutrients.

D without dairy?

Making sure kids get enough vitamin D can be a challenge. Food sources usually can't be relied on alone, and many of us live too far north to get appreciable amounts from sunlight year round. But beyond giving your kids more milk, there are some other things you can do.

• Take cod liver oil. Some brands of cod liver oil contain up to 400 IU of vitamin D per teaspoon. Flavored varieties are a hit with most kids.
• Catch some rays when they're around. During the spring, summer, and fall, make sure your little ones get some sun on their faces, arms, and legs. Just 5 to 15 minutes, 2 to 3 times per week will help boost their vitamin D levels.
• Try these foods. Egg yolks, fatty fish like salmon, tuna, and mackerel, and fortified foods all provide extra D. You can increase the vitamin D content of mushrooms by placing them in the summer sun for several hours before eating them. The mushrooms can maintain their vitamin D content for up to one year.
• Take a supplement. Your child's doctor may recommend giving your child a vitamin D supplement to boost their levels. Oil-based supplements tend to be better absorbed, as vitamin D is a fat-soluble nutrient. To avoid a rare but serious condition, children should not be given iron supplements unless directed by a doctor.

(Pediatrics 2013;131;e144)