This Is Why Vitamin D Is Important for Kids

drawing that illustrates how vitamin D is absorbed
Illustration by Dr. Gina Lamb-Amato

Vitamin D is a fat soluble vitamin needed by all babies and children. Vitamin D for kids is important, and they get vitamin D from sunlight and food. From April to the end of October, children who are outside playing for 15 to 30 minutes a day can absorb the daily recommended dose of vitamin D if their hands and faces are exposed. However, if children are wearing sunscreen, vitamin D cannot be absorbed through the skin and vitamin D supplements from food are necessary.

The following explains how vitamin D is absorbed and why vitamin D for kids is important, especially while COVID continues to be a challenge.

How does the absorption of vitamin D work?

When the skin is exposed to ultraviolet (UV) light, ultraviolet B (UVB) rays from the sun are converted in the body to vitamin D3. Vitamin D3 is transported to the liver, where it becomes 25-hydroxy vitamin D3, the major form of vitamin D that circulates in the body. It is then converted to 1, 25-dihydroxyvitamin D, which is the active form of vitamin D. Vitamin D works with calcium to help with children’s bone metabolism.

What are the benefits of vitamin D for kids? 

  • Supports kids’ immune systems against viral and bacterial respiratory infections
  • Is important in the growth and development of white blood cells, a type of immune cell
  • Contributes to brain development
  • Strengthens muscular development
  • Bone growth

Can vitamin D for kids help prevent COVID and other illnesses? 

During the COVID-19 pandemic lockdown, common childhood viral infections were, until recently, seen at a much lower rate in the pediatric population. COVID-19 preventive measures like lockdowns, mask-wearing, social distancing, staying inside, and cleaning surfaces at an increased frequency, prevented common respiratory and gastrointestinal viral infections from spreading in children.

Now that children, for the most part, are not in lockdown and the above COVID-19 preventive protocols have become more universally relaxed, pediatricians are seeing an uptick in respiratory and gastrointestinal diseases. Vitamin D is one of several immunity boosters for kids. As explained above, the natural way to get vitamin D is through sun exposure, but that is difficult because children often use sunscreen when outdoors.

Read Next | These Are the Health Benefits of Sunlight for Kids

What is the importance of bone growth?

Bones support kids’ bodies to support their weight despite bones not weighing a lot. Bones are essential to protect the body’s organs. The skull for example protects the brain. If children do not have strong bones to protect organs like the brain they will be at risk for injuries. Children with strong bones will take their strong bones into their adult and eventually older lives where they will be less likely to have bone weakness later when they are older.

Exercise is important for building strong bones. Weight bearing exercises like running, jumping, dancing, basketball, etc are good for building kids bones. Weight bearing exercises with muscles and gravity put pressure on bones. This pressure builds stronger bones. It is important that children spend at least 1 hour a day doing physical activities including weight bearing exercises.

Bones store Calcium which is vital for other body parts. It is important that children eat foods fortified with Vitamin D and Calcium because the amount of Vitamin D and Calcium and other minerals eaten is directly related to how much Calcium is stored in bones. This can be compared to giving a baby a bank account. Putting money in the bank account each year is like taking in Calcium and Vitamin D everyday. The more that is put into the bones or bank the more that will be there when a child becomes an adult. The bones of babies, children, and teens contain growth plates. These plates are made up of cartilage cells that grow and then become hard mineralized bone. Bone building and remodeling continues throughout life. However, the foundations that a child lays down developing their bones affects their bone health throughout their life as adults.

What are foods with vitamin D?

  • Salmon
  • Tuna
  • Liver
  • Fish oils

If children are not eating the above foods, it is important that they eat foods fortified with vitamin D, such as:

  • Milk
  • Yogurt
  • Cereal
  • Baby formula
  • Juice

What is the amount of vitamin D needed for babies, children, and adolescents?

Babies younger than 1 year of age need 400 IU vitamin D a day. Babies who are taking 32 ounces of formula a day are getting enough vitamin D. If they are breastfed or taking less than 32 ounces of formula then babies need a vitamin D supplement. Babies who are breastfed should be given a vitamin D supplement of 400 IU a day starting right after they are born.

Children older than 1 year to teen years of age need to take 400 to 600 IU of vitamin D a day.

What are the consequences of vitamin D deficiency?

Severe vitamin D deficiency causes rickets and osteomalacia, which are now usually only seen with very minimal sun exposure, nutrition where there is no fortified vitamin D foods, and in malabsorption syndromes.

There have been cases recently reported in the US of rickets because of children not taking in enough vitamin D either through sunlight absorption or through vitamin D-fortified foods. Rickets patients have enlarged skulls, joints of long bones, and rib cage curvature of the spine and femurs with generalized weakness. However, children have months of vitamin D deficiency before they present with these symptoms. Children with vitamin D deficiency can also present with growth failure, frequent respiratory infections, lethargy, and seizures. Children with chronic illnesses often need more than a 400 to 600 IU supplement a day.


Dr. Gina Lamb-Amato is a general pediatrician and developmental pediatrician who has worked in conjunction with Mount Sinai’s pediatric team. She has a master’s degree in child development and child psychology and works with various child psychologists, performing consultations and evaluations for children 0-12 years old. She also runs parent-child playgroups, where play, art, baby massage, and other techniques are used to help children develop optimally. She has training and expertise in Covid-19, having been on the frontlines. She does consultations for parents to help their children cope with the stress of the pandemic.

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