Children don’t spend any time thinking about their bones. So here’s some news for those who care for children: Make sure they get enough vitamin D. A recent study published in the Archives of Pediatrics and Adolescent Medicine found that low vitamin D levels were associated with stress fractures.
The study followed 6,712 athletic girls aged nine to sixteen for seven years, monitoring dairy, calcium, and vitamin D intakes. Over the seven years, 3.9 % developed stress fractures. Those with the highest vitamin D intake, though, suffered the fewest fractures.
This agrees with the correlation that many researchers are finding between bone health and vitamin D levels, and points to the need to protect bones even in childhood.
I recently listened to a fascinating lecture by Dr. Stasha Gominak on vitamin D. She’s a neurologist who has identified a most interesting connection between low vitamin D levels and poor sleep quality. She makes so many fascinating comments on the subject that I recommend you listen to all four parts of the lecture. However, something she brought to my attention that particularly relates to this post about children is the extent to which our vitamin D intake from sun exposure (the optimum kind of D) has dropped in one generation.
When I was growing up in the 60s and 70s no one in my suburb had central air conditioning; we played outdoors, and when the house got really hot we even ate outside, with no gazebo. We hadn’t yet heard of sunscreen, so our skin was fully exposed to the sun. Kids walked or biked to their destinations, and we were free to wander the neighbourhood. Our favourite activities involved a lot of moving around, usually with others, especially since there was nothing to watch on TV for most of the day. At least for the summer, we got all the vitamin D we needed (as well as a good bit of bone-building exercise).
By contrast, when my children came along in the late 80s the house was pleasantly cooled, so they stayed indoors a whole lot more to keep comfortable. Whenever they were outside we made sure they were slathered in sunscreen, effectively preventing their skin from making that essential vitamin D. Furthermore, since the world had grown much more aware of predators and other nasties, we drove them around as much as we could. And by then VCRs and video games gave them a lot of indoor entertainment. All told, in the name of improving their lifestyle, we deprived them from what’s proving to be a vital vitamin in preventing a dizzying number of diseases.
My conclusion from reading about vitamin D? When possible I must get 15 minutes per day of sun exposure on bare skin, no sunscreen. If I had children now I’d make sure they did, too. The rest of the year, supplements are essential.
Now back to the study I mentioned above. To the surprise of researchers, those with the highest dairy and calcium intakes also suffered the most fractures:
“In contrast, there was no evidence that calcium and dairy intakes were protective against developing a stress fracture or that soda intake was predictive of an increased risk of stress fracture or confounded the association between dairy, calcium or vitamin D intakes and fracture risk,” the authors comment.
The authors also note that in a stratified analysis that high calcium intake was associated with a greater risk of developing a stress fracture, although they suggest that “unexpected finding” warrants more study.”
Yup, calcium is not the key bone-builder. Make sure you get your vitamin D.