Cold days in the sun: How to get kids vitamin D in the winter

Because of winter's colder temperatures and shorter days, kids are likely spending more time indoors — limiting natural opportunities to absorb vitamin D. Vitamin D is a mineral that is necessary for your child's development, so it's important to make sure they get enough vitamin D in cold months, too. 

What is vitamin D? 

Conversations about bone health for kids often focus on calcium — a mineral found in milk and other foods. But vitamin D is crucial to bone health, too. Vitamin D regulates how much calcium and phosphorus are absorbed and stored in the bones. It also supports a healthy immune system response and has a positive impact on mental health. 

One of the body's major sources of vitamin D is exposure to sunlight, so during warmer months, children and adolescents can maintain healthy levels of vitamin D with time in direct sunlight. In colder months, kids may need to rely more heavily on dietary sources of vitamin D to meet their level of need. 

Where can kids get vitamin D? 

Direct exposure to sunlight allows the body to synthesize vitamin D, but throughout winter months when kids spend much of their time indoors, they're likely going to need to rely on dietary sources for vitamin D.

Vitamin D naturally occurs in a few foods. Try to work foods that are high in vitamin D into your child's diet, including: 

• Salmon (100-250 IU)
  
  
• Sardines (300 IU) 
  
  
• Tuna (236 IU)
  
  
• Mackerel (250 IU)
  
  
• Shiitake mushrooms (100 IU)
  
  
• Hard-boiled eggs (20 IU) 

For more kid-friendly options, look for foods that are fortified with vitamin D — meaning vitamin D is added during processing. Checking nutritional information on a food's label can help you determine how much vitamin D the food has been fortified with. Foods fortified with vitamin D often include: 

• Milk (100 IU per cup)
  
  
• Infant formula (100 IU per cup) 
  
  
• Yogurt (100 IU per cup) 
  
  
• Cheese (100 IU per 3 oz.)
  
  
• Breakfast cereal (40-100 IU per serving) 

Perhaps the easiest way to make sure your child is getting enough vitamin D is to have them take a daily multivitamin. Depending on the specific formula and brand, a multivitamin can contain anywhere from 400-1000 IU of vitamin D. A daily multivitamin can also provide other helpful nutrients that contribute to your child's overall health. 

How much vitamin D do kids need? 

The American Academy of Pediatrics recommends 400 IU of vitamin D per day for babies that are under one year old and 600 IU for toddlers, older children and adolescents.

A vitamin D deficiency can cause nutritional rickets, a condition that results in softening of the bones. Rickets is most easily recognized by bending or bowing of the leg bones, widening of the area above the wrists in infants or swelling of the ends of the ribs — conditions created from the stress of weight on soft bones that lack the necessary minerals. 

Other tips for bone health in kids 

Adequate levels of calcium and vitamin D are critical for bone health, but here are a few more things you can do to help kids develop healthy bones: 

• Serve vitamins with foods containing healthy fats. Vitamin D is fat-soluble, which means it's absorbed with other dietary fats. It'll be most efficiently absorbed when taken with another food containing healthy fats, like avocado. 

• Foster a well-balanced diet. Encourage kids to eat lots of nutrient-dense foods and foods that are high in protein, and limit foods that are high in sodium. High levels of sodium and low levels of protein can interfere with your child's ability to retain calcium. 

• Keep kids moving. The mechanical force from weight-bearing exercises improves the bones' abilities to accrue minerals. Engaging your child in high-impact, low-frequency activities like walking, jogging, jumping and dancing for at least 10 minutes, three times or more per week can also support healthy bone formation. Outdoor exercise can yield even more benefits for kids, so try to engage kids in active play outside — even when it’s cold. Bundle up and get out the sled, build a snowman, hike a winter trail or dig for treasure. 

As always, if you have any questions about your child’s health, please don’t hesitate to reach out to their pediatrician. That’s what we’re here for!

Roxanne Kane, MD Pediatrician Mayfair Pediatrics

Children’s Wisconsin has more than 20 primary care offices conveniently located throughout the Milwaukee area and southeast Wisconsin. Find a pediatrician near you.