Winter generally means less time outdoors in the sun, putting some kids at risk for vitamin D deficiency. Children need vitamin D, an important nutrient, to stay healthy.

What is vitamin D?

Vitamin D is a fat-soluble vitamin that acts as a mineral-controlling hormone in the body and helps to maintain normal blood levels of calcium and phosphorus. It is among the key determinants of bone health in children, along with genetics, the presence of chronic medical conditions, exercise and adequate calcium intake.

Sufficient levels of circulating vitamin D help prevent nutritional rickets in children and osteomalacia (softening of the bones, typically through a deficiency of vitamin D or calcium) in adults. A doctor can use a blood test to check your vitamin D levels.

Vitamin D precursors can be made in our skin from sunlight exposure or obtained from our diet in some of the foods we eat.

What foods provide vitamin D?

The U.S. Department of Agriculture provides a list of foods containing vitamin D. Some of the following foods provide it naturally, while others are fortified with vitamin D2 or D3:

• Fatty fish such as mackerel, salmon and tuna
• Beef liver, cheese, egg yolks and some mushrooms
• Most milk in the United States is fortified with 400 international units (IU) of vitamin D per quart
• Fortified foods include breakfast cereals, some orange juice, yogurt, margarine and soy beverages

Who is at risk of vitamin D deficiency?

Groups at risk of deficiency include exclusively breastfed infants, people with limited sun exposure, and people with conditions that disrupt their ability to absorb dietary fat such as ulcerative colitis, cystic fibrosis, and Crohn’s disease.

Most people get their vitamin D needs met through exposure to sunlight. However, concerns about staying protected from the sun due to skin cancer concerns may affect whether or not people are getting enough vitamin D from sun exposure. If possible, let your kids run around in the sun for five to 10 minutes before applying sunblock. It doesn’t take more than that amount of time for exposed skin to make a significant amount of vitamin D precursors.

In colder climates, when winter comes, people spend more time indoors, or if they are outdoors, they’re very bundled up so they get fewer opportunities to get vitamin D efficiently when the sun is less intense. In those cases, it may be necessary to add vitamin D supplements to your child’s diet.

How much vitamin D do I need?

The American Academy of Pediatrics’ (AAP) guidelines for vitamin D call for a minimum of 600 IUs daily in children ages 1 to 7 and 800 IUs daily for children 7 and older. The AAP’s recommended range is 600-1000 IUs daily for children.

However, it’s relatively safe to be on 1,000 IU per day without running the risk of vitamin D toxicity, especially in the winter and among individuals in high-risk groups. 

If you think your children are not getting enough vitamin D, ask your child’s pediatrician or healthcare provider for more information.