Vitamin D is important for absorbing calcium, building strong bones and preventing fractures. It has also been associated with additional functions in the body, including maintaining the immune system.

“We develop almost all of our bone mass before age 25, and that means it is very important for children to get enough vitamin D from the start,” says Michelle Vanstone, MD, a pediatrician with the Pediatric Metabolic Bone Clinic at St. Louis Children’s Hospital. “There are many factors that can prevent children and adolescents from getting enough vitamin D, including diet and reduced sun exposure.”

How Much Is Enough?
The body does not automatically create vitamin D. It is created in the skin after a person spends time in the sun, but most children do not make enough vitamin D from sun exposure. So most of this vitamin comes from eating a balanced diet.

Children younger than age 1 should be getting at least 400 international units (IUs) of vitamin D each day. That often presents a problem for babies who are partially or exclusively breastfed.

“Though breast milk is an ideal food for infants, there is very little vitamin D in it, and those levels may be even lower if the mother is vitamin D-deficient,” says Paul Hruz, MD, PhD, director of endocrinology and diabetes care at St. Louis Children’s Hospital. “We recommend all children who are breastfed take a daily vitamin D supplement to avoid complications with bone growth, such as rickets. When they get older, being active and eating a balanced diet rich in fruits, vegetables, low-fat dairy and vitamin D-enriched foods can help promote healthy bone growth.”

As children age, the amount of vitamin D they need increases to 600 IUs a day. Your child’s pediatrician can perform a blood test to check vitamin D levels, and let you know whether your child needs a supplement.


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