Over two years ago I wrote my first blog post about vitamin D and children.
This post was timed to coincide with the release of new guidelines issued by the Institute of Medicine about vitamin D. Since the end of 2010, there has been a huge amount of publicity and literature about this topic. So, given the interest in this topic, let’s update the older blog post a bit with some new findings and discussion.
First, about infants and their need for vitamin D. Recent studies have continued to show that 400 IU of vitamin D daily is the right amount for nearly all infants. The study released this week in JAMA showed that babies in Canada who received that dose had good levels of vitamin D (the form called 25-hydroxyvitamin D) in their blood, although the level was not as high as some might hope for. The authors of this article also found that exceeding what is believed to be the maximum safe level for vitamin D of 1000 IU day might lead to blood levels that were too high. In an editorial about this paper, I concluded that families can use this information to be comfortable that 400 IU per day is the right dose. Sometime in the future, there may be evidence that higher doses of vitamin D have important immune or other effects, but for now, the 400 IU daily dose is reasonable for virtually all infants.
For older children, in 2010 the IOM recommended 600 IU each day. We tested a dose of 1000 IU daily in a group of 4 to 8 year old children. We found that the 1000 IU supplement did not improve the ability of the children to absorb calcium and concluded that, at least for that purpose, there was no reason to consider the 600 IU dose inadequate.
There remain a lot of important unanswered questions about vitamin D and children. These include trying to decide who should have their 25-hydroxyvitamin D level in the blood tested. Some groups advocate for widespread testing. Others do not. I tend to be among those who do not believe that routine testing of most healthy children is needed, even among those who have dark skin or have a high body weight. We will await more data to tell us whether there is any clear clinical benefit to testing and giving more vitamin D in that circumstance. For now, consultation with your child’s pediatrician is best to help make this decision.
Important questions also exist about the role of vitamin D in treating other conditions or preventing other diseases. Again, we are waiting for good science about this, but for now, it is important to note no reliable data indicate that vitamin D can be used in place of influenza vaccine for example or in place of routine immunizations. Some conditions in which vitamins are not absorbed fully, such as cystic fibrosis or inflammatory bowel disease might also benefit from extra vitamin D and testing of vitamin D levels. But, we are far from identifying exactly which diseases will respond to higher vitamin D doses or determining the risks and benefits of high doses of any vitamins.
The world of vitamin D research is an exciting and active one. Someday we may have the ability to clearly identify which children (and adults) benefit from high amounts of vitamin D and which ones might have harm from high doses. For now, the recommendations from 2010 remain, in my view, the best ones for most healthy children.
For further reading on the topic, CNN recently published an article about the importance of vitamin D supplements in breastfed babies.