Could Vitamin D Supplements Have Prevented my Daughter’s Type 1 Diabetes?


A few months ago, our six-year-old daughter, Bisi, was diagnosed with type 1 diabetes. It’s a condition she will have to manage carefully for the rest of her life, to avoid the many terrible potential complications of the disease. Since the diagnosis, my husband and I have often said to one another things like: “What if we had…?” “Maybe if we had …” And the other will respond by (half) jokingly quoting back the text on the box of diabetes information we received at the hospital from the Lilly pharmaceutical company (which makes the insulin Bisi now must take with her meals): “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. It is as a disease where our own immune system attacks our pancreas, eventually shutting down its ability to produce insulin. But there are some emerging theories about what makes type 1 diabetes more likely. The most intriguing of these — the one that causes my husband and me to take the most deep breaths — is the theory that links 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 servicemembers diagnosed with type 1 diabetes with the vitamin D levels of a control group of servicemembers without diabetes. They found that those servicemembers 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.”

My husband and I don’t know that our daughter 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).

We live in New England, where 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 father was diagnosed with melanoma, a disease that killed him when the kids were 3 and 5. (My husband, 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 type 1 diabetes diagnosis, it was one of many causes–a kind of layering of effects. Bisi had a genetic susceptibility — we know now that type 1 diabetes is linked to other autoimmune diseases that run in our families. A virus like coxsackie, which many children get, may have increased her susceptibility. There may also be another, as yet undiscovered, environmental trigger. Type 1 diabetes 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 IU of vitamin D every day — Jamie, because as the sibling of someone with type 1 diabetes, he is at higher risk, and Bisi because there is some evidence that taking vitamin D can help extend the life of the few insulin-producing cells she still has.

This article originally appeared in the Atlantic.

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CarrieCatherinedave rothjoshJennifer Recent comment authors
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How did you decide on 2000 IU? I am Type 1, and give my 3-yr-old twins 1000 IU but am wondering if it is too much? The pediatrician always go with the general recommendation (I think it is only 400 for kids). I have read that if it is NOT fish oil (cod liver), it has to be a very high dose to be possibly effective. Do you have a resource for your dosage? I appreciate your post very much!!


Thanks, Katie, both for this article and for your blog. I’ve often felt grateful to have been diagnosed with T1 as a young adult (22) rather than as a child; at least I had a normal childhood, and — perhaps even more importantly — at least my parents didn’t have to worry about managing my blood sugars. I think that the parents of kids with type 1 are really unsung heroes.  As for Vitamin D, I’m writing a book about vitamins and thought you and others might be interested in this site put together by the Harvard School of Public… Read more »

dave roth
dave roth

Great article. You’re providing a valuable service in spreading the word about this issue.  We may not have the answer yet, but it only makes sense for parents to make sure that their children have adequate levels of Vitamin D.  It’s perfectly safe, so there’s little to lose. I’m amazed that more parents in sun-deprived areas don’t give supplements to their kids. That said, i agree that the what-if game  isn’t helpful.


What’s amazing about this piece is that it actually brings to light the fact that certain viruses can trigger auto-immunity and/or other chronic diseases later in life. This applies to cancers, too. Very interesting, and bravely helpful. I know a lot of people who don’t want to believe these things.


Great piece, and very good (and not so publicized) information for parents.


I believe your doctor is right.  Vitamin D, or the lack of it, can’t be blamed.  There are many factors involved and probably none of them are in our control.  Vitamin D is a good supplement that pretty much everyone should be taking.  But I think that it’s just one ingredient in the making of T1D.  Don’t play the “what if we had…” game.  It’s self-destructive.


The answer is yes, Type 1 diabetes is a vitamin D deficiency disease, overwhelmingly. Look at the research from northern Europe… Look at the rates of diagnosis in previous decades when vitamin D was supplemented in meaningful amounts… Since backing off in regards to mandatory/required supplementation Type 1 diabetes has SKYROCKETED. Regarding melanoma do your research on the latest findings…those who receive the least direct midday sun have the HIGHEST rates. I don’t care what your derm says- he/she is trying to protect their profession from the HORRIBLE advice to wear sunscreen before they were thoroughly tested. 98% of all… Read more »

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