Recently The Seattle Times ran an article posing this question: Is it time to stop taking vitamin D?
The article and several others like it that ran in news outlets across the county, detailing a growing body of research that has debunked high doses of vitamin D as a sort of wonder drug for for numerous medical conditions.
And yet, the American Academy of Pediatrics, the Centers for Disease Control and Prevention and working pediatricians have long stressed the importance of vitamin D supplementation for infants, children and young adults.
Do the studies challenging the efficacy of high-dose vitamin D supplementation in adults change that advice?
The answer is no, according to Dr. Kate Ness, a clinical professor at Seattle Children’s Hospital. Dr. Ness says it is very difficult for children – or adults for that matter – to get enough vitamin D from food sources or the sun, particularly in the Pacific Northwest. Almost all children, she says, need an extra boost of D in the form of a multivitamin or vitamin D drop.
Dr. Ness sat down with Seattle’s Child to discuss vitamin D and what parents need to know to keep kids healthy — especially as they read or learn about research on high-dose supplementation in adults.
Seattle’s Child: Do headlines questioning vitamin D supplementation concern you?
Dr. Ness. They do. When the most recent study was first published it made the New York Times, the Seattle Times, the science papers. And I immediately worried ‘Are families going to be less likely to give their kids vitamin D as a result of seeing this?’ News about research can get confusing.
But, I’ll cut to the chase: I don’t think children should stop taking vitamin D. It’s important for parents to understand that the study that made the headlines only looked at adults aged 50 and older. No children were included, and no conclusions can be made from the article about vitamin D and children. So I’m not changing my practice of advising parents to supplement kids.
Seattle’s Child: What does vitamin D do in the body? Why is it important?
Dr. Ness: We need vitamin D to help us absorb calcium. If we don’t have enough vitamin D, we’re not able to absorb the calcium in our diet adequately. As a result, you can wind up having low calcium levels in your blood, which can lead to real problems.
Seattle’s Child: Kids are growing bones and tissue, is low Vitamin D particularly worrisome for them?
Dr. Ness: That’s exactly right. Vitamin D deficiency can cause rickets, a condition in which a child is not getting enough minerals, calcium and phosphorus in particular, into their bones. As a result of that inadequate mineralization of the bones, the bones start to form differently, and you can see changes in the bone structure.
Specifically what we might see is the bowing of the legs or very pronounced knock knees, widening of the wrists and delayed closure of the soft spot (fontanelle) in the skull. Kids can experience slow growth and developmental delays. They may have pain and irritability. Sometimes even just giving them a hug can cause discomfort.
Seattle’s Child: Isn’t rickets a disease of centuries past? Is it a real issue here in the Pacific Northwest?
Dr. Ness: We absolutely still see rickets and in fact one of my recent cases was a child with rickets. It seems like something that used to happen 100 years ago, but it still happens here and now in Seattle.
Seattle’s Child: So how do we get vitamin D?
Dr. Ness: Vitamin D occurs naturally in foods, but it’s very limited. For example, it’s in fatty fish, egg yolks and organ meats like liver and kidney. But I don’t know many kids that eat a lot of fatty fish and liver. So there are foods like milk, including alternative milks, and formulas that are fortified with vitamin D to help. The trick is kids that have to drink a full liter of milk or formula a day to get the 400 units of vitamin D that is the minimum recommendation for them.
Sun exposure is another source of vitamin D. But, we are at a fairly high latitude in Seattle, which means we really only get adequate sun exposure to make vitamin D efficiently through our skin during a couple of months in the summer. Also, the lighter your skin, the more efficiently that process happens. People who have more pigment or who have darker skin require much more sun exposure to make vitamin D in their skin so they are at higher risk for developing vitamin D deficiency.
Seattle’s Child: How much vitamin D do kids need?
Dr. Ness: The minimum vitamin D intake is 400 international units (IUs) for an infant and 600 to 800 IUs for children age 1 year to adulthood.
Seattle’s Child: Can they get enough from the food sources you mentioned?
Dr. Ness: Given the limited natural sources for vitamin D, the months with less sun we experience here, and fact that most kids aren’t drinking a liter of milk a day, it’s hard. Which is why supplementing vitamin D is important for most children in this area.
Just for some perspective: girls grow in height until about age 15 years. Boys, on average, grow in height until age 17 years. But even when kids are done growing in height, they continue to build their bone density into their mid-20s. They need vitamin D supplementation to prevent things like rickets because their bones are growing and developing so rapidly. And this makes them a very different population from the middle and older age adults included in the recent study who long ago completed their growth and achieved their maximum bone density.
Vitamin D supplements are something that I recommend for just about all kids at all ages in Seattle.
Seattle’s Child: Do childrens’ multivitamins meet the vitamin D most recommendations?
Dr. Ness: Kids can get the recommended amount through multivitamins, but I also think it’s important for parents to look at labels to find out exactly how much they’re getting. Vitamin D drops can also be easily given and are especially good for babies. If an infant is drinking from a bottle, you can put that drop of vitamin D right in the bottle. Or, if they’re nursing exclusively, put it on the mother’s breast so the baby can get it directly that way.
I’m not particularly directive in terms of what form of vitamin D is given to kids, only that they get it.
Seattle’s Child: Don’t exclusively nursing babies get all they need from breast milk?
Dr. Ness: No. One of the main populations where we see clinically significant vitamin D deficiency is exclusively breastfed babies who are not getting a supplement. Breast milk is wonderful in many, many ways, but it does not have very much vitamin D in it.
Remember I said a child would have to drink a liter of cow’s milk fortified with vitamin D to get 400 IUs? By comparison, a liter of breast milk has somewhere in the range of 10 to 50 IUs of vitamin D. So unless the mother is taking very high doses of vitamin D, it’s really unlikely a breastfed child is going to get enough vitamin D without supplementation.
We recommend supplemental vitamin D as long as babies are exclusively breastfed, until the point where they’re getting at least a liter of formula and or cow’s milk a day.
Seattle’s Child: Do homemade formulas cover vitamin D?
Dr. Ness: Over the last few years, we have seen several children with severe vitamin D deficiency and rickets caused by homemade formulas. Families put a tremendous amount of work into making the formulas, but they didn’t have vitamin D or much calcium. It’s kind of heartbreaking because as a provider you can see how hard the families were working to try to do what they thought was right for their child, but it didn’t meet all of their child’s needs.
Seattle’s Child: Some vitamin D supplements come in doses higher than 1,000 IUs. Is there a problem with giving kids higher doses just to be sure they are covered?
Dr. Ness: Dosing does get a little nuanced. That 400 to 800 IUs is enough as long as the child is vitamin D sufficient.
If they are truly vitamin D deficient we sometimes will recommend higher doses but only for a limited period of time — generally a couple of months to get their levels up into the normal range. Then we back off to that 400 to 800 IU level.
There is, in fact, some risk to giving 1,000 or more units of vitamin D a day. Specifically, it can cause very high calcium levels in the blood and can lead to kidney stones. We really want to avoid that.
There are some older kids and teenagers for whom I will sometimes recommend a higher dose, but only if I think they’re at higher risk of deficiency related to underlying medical conditions.
Seattle’s Child: Which medical conditions can lead to vitamin d deficiency?
Dr. Ness: Medical conditions which reduce gastrointestinal absorption can lead to low levels, such as celiac disease, inflammatory bowel disease and cystic fibrosis. There are also medications which can reduce vitamin D levels and effectiveness, such as anti-seizure medications and steroids.
Seattle’s Child: Should kids be regularly tested for vitamin D?
Dr. Ness: We don’t recommend it routinely for otherwise healthy children. Instead, we suggest trying to get kids the recommended daily amount of vitamin D. We do recommend testing for kids who have certain chronic diseases, concerns about bone fragility, or symptoms of rickets.
Seattle’s Child: You mentioned developmental delays, knock knees, leg bowing and pain are signs of rickets. Can rickets be reversed?
Dr. Ness: Yes! Nutritional rickets is preventable, but it’s also very treatable. We give the kids higher doses of vitamin D and calcium to replenish their bones and get their vitamin D levels up to the normal range. And it fixes the problems. Developmental delays typically catch up.
Seattle’s Child: Where should families get the vitamin information they need to make good decisions?
Dr. Ness: It’s important that families have conversations with their pediatricians. These sources are also helpful: Vitamin D for Babies, Children & Adolescents from Healthychildren.org and Vitamin D from the Centers for Disease Control and Prevention.