What parents should know about vitamin D for kids

Vitamin D helps regulate calcium and phosphate levels in the body that are important for bone development and strength.

But vitamin D's role in promoting good health may go even further. Research has explored vitamin D's role in boosting the body's immune system. Recently, several studies have even looked at the role of vitamin D in reducing risk of illness from COVID‑19.

While more is being learned about the benefits of vitamin D, it's an essential part of keeping your child's bones strong as they develop. Sarah E. Barlow, M.D., a pediatric gastroenterologist and Director of Children's Health℠ Integrated Program in Childhood Obesity and Professor at UT Southwestern, explains how to ensure your kids are getting enough vitamin D.

What does vitamin D do?

Vitamin D helps the body appropriately absorb and regulate calcium, which is essential for bone health. Without enough vitamin D, kids may suffer from weak or brittle bones that break easily. They can also develop rickets, a bone condition caused by severe vitamin D deficiency. Rickets can lead to bowed legs and stunted growth.

"The primary function for vitamin D, the one we focus on the most, is bone health," explains Dr. Barlow. "Vitamin D acts almost like a construction site supervisor. It makes sure the materials we need for strong bones – such as calcium and phosphate – are where they need to be, and in the correct amounts."

How much vitamin D do kids need?

Different amounts of vitamin D are recommended based on a child's age. The National Institutes of Health (NIH) recommends the following:

• Infants should receive at least 400 International Units (IU) of vitamin D daily from birth to 12 months.
• Children ages 1 through 18 should aim for 600 IU of vitamin D daily.

What are sources of vitamin D?

Sources of vitamin D include sunshine and certain foods. Our skin naturally produces vitamin D when exposed to sunlight. That's why vitamin D is referred to as "the sunshine vitamin." Most people can get the right amount of vitamin D from just 10-15 minutes of direct sun exposure a few times a week. However, during winter, or for children in a cloudy climate or who do not spend much time outdoors, vitamin D would need to come from food sources. As a reminder, it's important not to overdo sun exposure, as it can increase risk of skin cancer later in life. Always apply sunscreen if your child is outside for more than 15 minutes.

Vitamin D can also be found naturally in fish like salmon, herring and tuna. Many children do not eat fish like these every day, but thankfully, other foods and beverages are fortified with vitamin D – such as milk, yogurt and breakfast cereals. Including these enriched foods as part of a well-balanced diet is an excellent way to help your child get enough vitamin D.

"It's always important for families to take a good, overall look at their children's diet to make sure they're getting the right nutrients," Dr. Barlow recommends.

Does my child need a vitamin D supplement?

Because breast milk is not a good source of vitamin D, breastfed infants should be given 400 IU of vitamin D daily, beginning soon after birth and continuing at least until they start eating solid foods. This supplement can be given through liquid vitamin D drops. Formula-fed babies should also receive a liquid vitamin D supplement until they drink at least 32 ounces of vitamin D-fortified formula per day.

If you are concerned that your child or teenager is not receiving enough vitamin D from diet or sun exposure, ask your pediatrician if a supplement is needed. A daily multivitamin for kids would include the recommended daily allowance for vitamin D.

If you opt to give your child vitamin D supplements, be mindful of the recommended daily allowances for your child's age. "It's possible to have too much vitamin D, and when that happens, kids can develop kidney stones," Dr. Barlow says.

What are signs of vitamin D deficiency in children?

Children with only a mild vitamin D deficiency will likely show few, if any, symptoms. Kids with extremely low levels of vitamin D may feel tired and complain of bone or muscle pain. In the most severe cases, they may experience frequent bone breaks or develop rickets.

Children with darker skin may be more at risk for developing vitamin D deficiency than others. "If you have dark skin, the melanin – or pigment – in the skin reduces the body's ability to produce vitamin D as effectively," Dr. Barlow explains.

If you feel your child is not getting enough vitamin D, ask your pediatrician to check their levels using a simple blood test.

Vitamin D and COVID-19

Recent studies have explored a possible link between vitamin D deficiency and risk for COVID-19. One study suggests that healthy vitamin D levels may reduce the chance of developing COVID-19.

"The study took patients who tested positive for COVID-19 and then looked back to see if they had been diagnosed with a vitamin D deficiency in the previous 12 months," Dr. Barlow explains. "It found that patients who had lower vitamin D levels were more likely to have a positive COVID-19 test. It's not completely clear why, but it's possible low vitamin D levels may not be the cause of virus susceptibility but rather a marker, which is tagging along with other underlying health problems."

It's important to know that research on COVID-19 is ongoing, and these results are not definitive. Also, there is no research suggesting that taking extra vitamin D would be helpful to anyone who has enough vitamin D already.

While more research is needed to understand vitamin D's role in staying healthy during the coronavirus pandemic, there is no question that it has other proven benefits for your child's health.

"Kids need vitamin D," says Dr. Barlow. "It plays an essential role in regulating bone-building and ensuring there is the right amount of calcium to build strong bones – which is, of course, very important for growing children."

Learn more

Have additional questions about your child's nutritional health? Children's Health is home to one of the largest pediatric nutrition teams in Texas. Learn more about the benefits of healthy eating and see more tips for eating healthy at home.

For more information about COVID-19 and resources to help keep your family healthy during this time, visit the Children's Health COVID-19 hub.