Connecting the Dots between Diabetes and Vitamin D

When we were in the hospital, Bisi received a box of diabetes information from the Lilly pharmaceutical company (the same company that produced the Disney diabetes cookbook and that makes the insulin Bisi takes with her meals). The text on the box never failed to crack Mark and me up, in a black humor kind of way. It became especially useful in those inevitable moments where one of us would say something like: “if only we had…” “what if we had…?” The other would respond by  (half) jokingly quoting back the text on the Lilly box: “Pause. Take a deep breath. And remember: You couldn’t have prevented what’s happening with your child, so try not to beat yourself up.”

The truth is, there is no known way to prevent type 1 diabetes, an autoimmune disease where the immune system attacks the pancreas, eventually shutting down its ability to produce insulin, which regulates our blood sugar when we eat. But there are some emerging theories about what makes type 1 diabetes more likely. The most intriguing of these—the one that causes Mark and me to take the most deep breaths—is the vitamin D theory, linking low vitamin D levels to type 1 diabetes.

Several studies have shown this link, including one published in September in the journal Diabetologia. In that study, researchers from the Naval Health Research Center in San Diego and from universities in California and Florida compared the vitamin D levels of military service members diagnosed with T1D with the vitamin D levels of a control group of service members without diabetes. They found that those service members with the lowest concentration of vitamin D in their blood were 3.5 times more likely to develop diabetes than their peers with the highest vitamin D levels.  In 2008, the Archives of Disease in Childhood published a meta-analysis of observational data from four studies of vitamin D intake by young children in various European countries. Their conclusion:  “children being supplemented had a 29% reduction in risk of developing type 1 diabetes compared with their peers who were not being supplemented.”

Mark and I don’t know that Bisi was vitamin D deficient—blood tests for vitamin D levels in children are not standard, even though the American Academy of Pediatrics estimates that more than 75% of infants aren’t given the recommended amount of vitamin D, and even though low levels of vitamin D have been implicated in a wide range of conditions, including cardiovascular disease, osteoporosis, multiple sclerosis, and some cancers. But we think it’s pretty likely her level was low. We weren’t all that great about giving her the vitamin D drops that her pediatrician recommended for breastfed infants (formula is fortified with vitamin D). In New England, the angle of the sun is such that the summer months are the only ones where you can get sufficient vitamin D from the sun’s rays. And I had been obsessively slathering Bisi and her brother, Jamie, with sunscreen ever since my dad was diagnosed with melanoma, a disease that killed him when the kids were 3 and 5. (Mark, and it seems in retrospect that he was right, always argued for the kids to get their 15 minutes in the sun with no sunscreen, so they could get their vitamin D.) In any case, many of the health benefits of vitamin D are thought to begin at much higher levels than the current RDA of 400 IUs for infants and children (the recommendation was upped from 200 in 2008).

In the hospital, Bisi’s endocrinologist told us that if low vitamin D levels contributed to Bisi’s diagnosis, it was one of many causes—a kind of layering of effects. Bisi had a genetic susceptibility—we know now that T1D is linked to other autoimmune diseases that run in our families. A virus like coxsackie, which many children get, may have increased her susceptibility. (This is another “take a deep breath” topic for us. I can’t help thinking back to the time when ten-month-old Bisi got a raging case of coxsackie, which is transmitted through feces, after spending a vacation in the Caribbean crawling around on an outdoor veranda where wild rabbits hopped around and inevitably pooped. We tried to keep her hands clean, but…) There may also be another, as yet undiscovered, environmental trigger. T1D increased 23% in the U.S. from 2001-2009, and worldwide it’s increasing at a rate of about 3% a year. No one knows exactly why.  Still, at least in Bisi’s doctor’s view, vitamin D is an important part of the puzzle. “Do you have another child?” he asked us in the hospital. We told him about Jamie, who is 8. “Give him vitamin D supplements.”

Now, both of our children are taking 2,000 IUs of vitamin D a day—Jamie, because as the sibling of someone with T1D, he is at higher risk. Bisi, because there is some evidence that taking vitamin D can help extend the life of the few insulin-producing cells she still has. (They're also getting tested to make sure they're not taking too much.)

So, pause. Take a deep breath. And remember:  You should make sure your kids are getting enough vitamin D.