Vitamin D for Kids: How I Think About It as a Pediatrician and Mom

Vitamin D gets a lot of attention, and for good reason. It plays an important role in calcium absorption and bone health, and it also has functions in muscles, nerves, and the immune system.

But vitamin D is also a perfect example of why I do not like simplistic supplement advice. I see parents get pulled in two directions: either vitamin D is treated as something every child needs in very high amounts, or it is treated as an afterthought. I think the better approach is somewhere in the middle—understand what the nutrient does, know the reference points, look at the child’s actual situation, and avoid assuming that more is always better.

Children do need vitamin D

For children ages 1–18, the U.S. Recommended Dietary Allowance is 15 mcg, or 600 IU, per day. Infants have separate recommendations: the American Academy of Pediatrics recommends 400 IU (10 mcg) a day for infants under one year.

That number is useful because it gives us a population-level reference point. It is not a personalized prescription for every child, and it does not tell you everything about what a specific child may need in a specific situation.

Food, sunlight, and supplements all contribute

Vitamin D can come from foods, fortified foods, supplements, and production in the skin after sun exposure. In practice, children can have very different total intake even if their families feel they are eating similarly.

Some children drink fortified milk every day. Some drink plant milks that vary widely in fortification. Some eat eggs or fatty fish regularly. Others eat almost none of those foods. Sun exposure also varies with season, geography, skin pigmentation, sunscreen use, clothing, and lifestyle.

This is why I prefer to look at the whole picture instead of assuming that every child needs the same plan.

Do not forget fortified foods

Fortified foods are easy to overlook because they do not feel like “supplements,” but they count. Milk, some plant milks, breakfast cereals, and other foods can contribute meaningful vitamin D.

When I review a child’s intake, I count those sources too. The practical lesson is simple: look at the whole day, not just one bottle.

Why a pediatrician may sometimes check a vitamin D level

There are situations where measuring vitamin D can be useful, especially when there is a clinical reason to look more closely. But I do not think every healthy child needs repeated testing simply because testing exists.

Laboratory testing is most useful when it helps answer a question or guide a plan. That might include a history of deficiency, certain medical conditions, concerns about bone health, or a situation where a clinician is monitoring treatment.

For me, the point is not “test everyone.” It is “test when the result will actually help you make a better decision.”

What the newest guidance says

In 2024, the Endocrine Society suggested vitamin D supplementation for children and adolescents ages 1–18 to prevent nutritional rickets and potentially lower the risk of respiratory infections. Supplementation in that guideline could come from fortified foods, a multivitamin, or a vitamin D supplement.

It was graded as a weak recommendation based on low-certainty evidence, and I think that is the honest way to describe it to parents: a reasonable, everyday amount makes sense for many children, but it is not a miracle and it is not a reason to megadose.

Know the upper limits

Vitamin D has age-specific Tolerable Upper Intake Levels. For healthy children, those limits rise with age—from 2,500 IU per day for ages 1–3 to 3,000 IU for ages 4–8 and 4,000 IU for ages 9–18. Those limits include intake from food, beverages, and supplements.

A clinician may use higher amounts temporarily to treat a documented deficiency, but that is medical treatment—not a reason for families to assume that megadosing is better.

This is one of the reasons I dislike supplement advice that focuses only on the largest number. A higher number on the front of a bottle does not automatically mean a better product or a better plan.

Look at the whole supplement stack

This matters especially when children take more than one product. A multivitamin may contain vitamin D. An omega-3 may contain vitamin D. Then a separate vitamin D product may be added on top. Families can unintentionally stack the same nutrient from several directions.

I always want parents to add up overlapping nutrients rather than thinking about each bottle in isolation. The same principle applies to other nutrients as well.

What I think about at home

As a mom, I want a plan that is simple enough to follow consistently. I do not want to turn breakfast into a chemistry experiment. I want to know what my children are getting from food, what is already in the products we use, and whether there is actually a reason to add more.

I will admit that curiosity got the best of me, and I checked vitamin D levels on all of my kids, and my husband. Our family eats fairly well. Even so, most of them came back low. I do not share that to suggest every family needs lab work. I share it because it changed how I think about the “they eat healthy, so they’re fine” assumption, especially for a nutrient that is hard to get from food alone.

That is also how I think in practice. Thoughtful does not have to mean complicated.

My bottom line

Vitamin D matters. Context matters too.

I prefer thoughtful dosing over chasing the biggest number on the label. Look at food, fortified foods, overlapping supplements, age, and the individual child. And when a child needs something different from the general recommendation, that should be a deliberate decision—not an accident of stacking products.

— Dr. Katie Good, MD

Sources & further reading

This article is for general education and is not a substitute for individualized medical advice. If you have questions about your child’s nutrition, supplements, growth, medications, or laboratory results, talk with your child’s pediatrician or healthcare professional.