Vitamin D in Breastmilk and My Daughter’s Diagnosis with Type 1 Diabetes

Sydney, catching bubbles at her birthday party this month.

A few weeks ago, I was all set to write about the vitamin D needs of pregnant and nursing women. Increased sunscreen use and less time spent outdoors means that few women can meet their vitamin D needs through sunlight exposure alone. As a result, many pregnant women are insufficient in the vitamin.

The medical community is clearly concerned about women’s low levels of vitamin D: The American Pregnancy Association recently raised their recommended vitamin D intake for pregnant and nursing women from 400 IU to 4000 IU, a tenfold increase. The change was precipitated by a recent randomized control trial, in which supplementation with 4,000 IUs a day was shown to be safe and highly effective at reducing vitamin D deficiency among pregnant women.

I only wish these changes had come sooner.

I say this because last weekend, my daughter Sydney, who turned two this month, was diagnosed with Type 1 Diabetes–a disease that may be staved off, in part, by high levels of vitamin D during infancy.

What is Type 1 Diabetes?

Unlike its much more common cousin, Type 2 Diabetes, Type 1 is not driven largely by obesity, a sedentary lifestyle, and a poor diet.

Type 1 Diabetes is an autoimmune disease, in which the body’s immune system, for unknown reasons, launches a targeted and fatal attack on the islet cells of the pancreas.

These pancreatic islet cells are essential for life. They act as the body’s blood sugar thermostat, secreting insulin–the hormone that allows our muscle and liver cells to absorb sugar. Without insulin, we cannot make use of the carbohydrates we eat.

Once the islet cells are gone, the body goes into starvation mode, burning fat in a desperate attempt to fuel itself–a process which, without treatment, leads inexorably to kidney failure and death. Before the development of insulin therapy, Type 1 Diabetes was always fatal. A hundred years ago, my daughter would have had at most another year or two to live.

Insulin provides the down arrow on the body’s sugar thermostat. But no less critically, the islet cells also control the up arrow on the thermostat: a hormone called glucagon. When our blood sugar levels drop, glucagon prompts the liver to release some of its sugar stores into the blood. During times of fasting or intense exercise, glucagon protects us from hypoglycemia.

Because people with Type 1 lack glucagon, they must, at all times, carry rapid-acting sugars and injectable glucagon (the equivalent of an epi-pen for diabetes). Their bodies can no longer compensate for an excess of insulin or a precipitous drop in blood sugar. Something as simple as a mistimed or overly large dose of insulin can lead to hypoglycemia, disorientation, coma, and even death.

The disease is now manageable, albeit with considerable effort and oversight. Even with sound management, though, my daughter faces a greatly increased odds of kidney failure, retinopathy, and heart disease. And because she was diagnosed so young, she is at high risk for subtle cognitive problems later in life.

Children’s rapidly growing brains need a steady supply of glucose, but not too much. The cognitive problems found in people with diabetes were once believed to be mainly caused by episodes of severe hypoglycemia. New research, though, suggests that brain development is harmed by both too low and too high levels of blood sugar. We must chart a narrow and uncertain course at my daughter’s every meal.

The difficulty of keeping my daughter in balance illustrates how beautifully our biology normally does its job. To manage her condition, we must now check my daughter’s blood sugar 6-10 times a day, including at midnight. We must count her carbohydrate intake at every meal–no easy task with a two-year-old–and inject her with insulin whenever she eats bread, pasta, fruit, or any other food containing significant amounts of carbohydrates.

Why Did This Happen To My Daughter?

When your small child falls ill, nothing plagues you like the question of why. Why? What could I have done differently?

When it comes to Type 1 Diabetes, there is no good answer. But it’s a big question these days, because Type 1 Diabetes is on the rise, especially for children under 5, among whom the incidence has increased sevenfold. Genetics certainly plays a role, but concordance between identical twins is only about 30-40%, and genetics cannot account for the rapid worldwide increase in Type 1 over the last 50 to 60 years. Environmental factors have to contribute.

One popular theory holds that a viral infection can trigger the condition in the genetically predisposed. In mice and rats genetically modified to have a high risk of diabetes, certain viral infections can cause their immune systems to attack their pancreatic islet cells. Alterations in the gut microbiome may also play a role. We do not really know.

Another possible contributor is our historically low levels of vitamin D. Vitamin D is a known immune system modulator, and is believed to have a critical role in preventing autoimmune diseases. In one large study prospective study conducted in Finland, the country with the highest rate of Type 1 Diabetes in the world, regular supplementation with vitamin D reduced the odds of developing Type 1 Diabetes tenfold. Perhaps not coincidentally, for much of the year in Finland, there is too little sunlight for skin-based vitamin D synthesis, making supplementation with vitamin D or consumption of good dietary sources, such as fatty fish, essential. A meta-analysis using data from seven European countries found the same effect: vitamin D supplementation during infancy reduced the risk of childhood diabetes, although the effect was not as large as found in the Finnish study.

Vitamin D

For exclusively breastfeeding mothers, supplementation may be especially important. The amount of vitamin D in breast milk corresponds to the mother’s own levels. With our reduced exposure to sunlight and increased use of sunscreen, many nursing women are deficient. As a result, most breastfeeding babies do not receive enough vitamin D during their first year of life.

The old recommendation for nursing mothers of 400 IUs a day is not enough to boost the levels of vitamin D in breastmilk. Supplementation of around 4000 IUs a day is needed to provide an exclusively breastfeeding infant with 400 IUs, the current recommended daily allowance for infants.

I gave my daughter vitamin D drops, but with her being my second, and with the insane-a-thon of wrangling my then two-year-old son while caring for a newborn, I do not remember if I did so every day. And in my prenatal vitamins, I only took the old recommended amount of about 400 IU.

What if I had taken 4000 IU during her first year of life? Would it have made a difference? Would she have been diagnosed with diabetes later, or not at all? I will never know. It is an ultimately fruitless line of inquiry, but one I have trouble letting go of. Could something so simple have made such a difference to her life?

I know that I cannot beat myself up over this, that whatever I may have done wrong, I also did lots of things right. After all, we still do not know, and may never know, the true reasons why she developed this terrible disease. After all, while the vast majority of infants in the U.S. do not receive vitamin D supplements and do not meet the recommended daily allowance of 400 IUs a day, only a very few will ever develop Type 1 Diabetes. Even if a low level of vitamin D somehow contributed, it is far from sufficient to explain her diagnosis.


Sydney in the hospital following her diagnosis. She has a brace on her arm to cover her IV.


My daughter’s diagnosis was a shock. She has always been such a healthy, happy, playful little thing. In the weeks leading up to her diagnosis, she was not sick or weak or obviously unhappy; she just had a nasty-looking yeast diaper rash that would not go away, despite treatment.

It was odd, and it troubled me. At first, I blamed her daycare, wondering if her teachers were not changing her diaper often enough. But her teachers were clearly responsible and caring, so that explanation did not really hold water. Eventually, I looked up causes of yeast infections in children and saw that the they could the result of untreated diabetes.

And then, worryingly, the symptoms lined up: she did pee a lot, she was always thirsty, she had been unusually cranky of late. I bought urine strips to test for glucose, and they came back faintly positive. I reassured myself that they were just contaminated, but took her straight to the doctor anyway.

After a brief physical exam, the doctor told us that she was not concerned. Sydney seemed perfectly healthy. But she would test her blood sugar just as a precaution.

It came back at 470, sky high. For people without diabetes, a blood sugar level above 200 is rare.

Despite my initial concerns, her diagnosis was a shock. In the space of an instant, I became a grieving mother of a very sick little girl. You are present as they rush to treat her, to bring her blood sugar down by IV, to test her blood for other awful consequences of hyperglycemia, but you are also not present. You somehow hold in your tears, you cradle your child and sing to her, and you force a big smile as the nurse inserts her IV. The whole process passes as if in a blur. It feels so surreal.

My daughter is doing well now, under our careful supervision. But I am still grieving for the life I once pictured for us, which in retrospect seems so carefree. I am grieving for the additional stress and anxiety that my husband and I feel as parents, and for the unexpected lifelong burden my daughter will have to bear.

Her diagnosis upended what I now realize was major mental life raft for me, amidst the vast sea of potential parental angst and guilt. When you have a child, as the saying goes, your heart lives outside your body. To counter the continual, crazy-making anxiety that something might happen to your child, you have to repeatedly talk yourself down. You remind yourself that kids are pretty resilient, and that most of what you do or do not do probably will does not matter that much anyway–regardless of what their psychoanalyst might claim 30 years from now. Children need love, attention, and a safe and reasonably happy home. The rest is pretty much up to them.

For my daughter, and for my husband and me, that is no longer true. Sydney now needs careful monitoring, all day long, of her food intake, her blood sugar, her activity levels, her moods, and her insulin doses. Multiple times a day I have to inject her with insulin, a nerve-wracking task. Inject too much and I could send her into a coma. Inject too little and high blood sugar will slowly wreak havoc with her eyes, heart, brain, and kidneys.

It is scary and stressful, and we are still adjusting, in ways big and small. At the same time, I know that we will get through this, that this is not the worst thing that could happen, not by far. And I know we will find ways to manage her condition.

We have to be grateful: recent advances in medical treatment for diabetes, such as insulin pumps and implantable glucose monitors, mean that Sydney stands a very good shot at having a full, adventurous, happy life.

And for me, I find that having small children provides remarkable emotional clarity. The answer to will you hold your shit together? has to be, simply: Yes.

Like this post? Don’t forget, sharing is sweet!

Author: Amy Kiefer

As a former research scientist and proud mama of three little munchkins, I love digging into the research on all things baby-related and sharing it with my readers.

14 thoughts on “Vitamin D in Breastmilk and My Daughter’s Diagnosis with Type 1 Diabetes”

  1. Amy, I can only imagine what you and your family have gone through and are going through. You are right that we wear our hearts outside of ourselves and we have to find ways to live with that and all that entails. I appreciate this beautiful piece and I wish you and your family the best as you adapt to the new normal.

    1. Thank you, Jessica, for your kind words. We are hanging in there, and Sydney is doing great, but I still have my days. One of the diabetes educators told me “we all have bad diabetes days,” and that sounds about right.

  2. It is scary… Very glad to hear that you will be supplementing. The recent increase in recommended amount of vitamin D was made with surprisingly little fanfare. I do not remember my pediatrician mentioning *anything* about vitamin D to me, let alone that I was supposed to be taking 4000 IUs a day.

    By the way, what was the other post on vitamin D deficiency?

  3. Hi,
    I realize this is a late reply, but as a fellow type 1 diabetic, I just wanted to say hang in there, as those first few months dealing with T1 are the worst…I was diagnosed after being on study abroad in a cloudy European country for a year, and always wonder if decreased vitamin D had a role…I also wanted to give an enthusiastic plug for both cgms and pumping, whenever your endo team feels comfortable with it– the data to look at trends and ability to make small tweaks with a pump are both great management tools. I think at this rate we’ll have a ‘technological’ cure long before a ‘biological’ one.

    1. Thanks for the encouragement! We still have our ups and downs, but yes, the first few months were much worse. There’s just a lot to figure out. It took about a month to get set up with a pump, her insulin dose was all over the place, etc. We do have a CGM, and it is the best thing ever. The two hours a week it has to reboot are the worst! I cannot imagine trying to manage blood sugar without one. It would be like flying blind.

      As for the vitamin D, who knows? Of late, I’ve also started wondering about the role of the gut microbiome and antibiotics. I ended up on two courses of antibiotics (unnecessarily, as it turned out) in my last month of pregnancy, and then IV antibiotics during labor for Group B strep. The research on antibiotics is unclear, but there is accumulating evidence for derangement of the gut flora.

    1. This is an area of active research, but I don’t think anyone has figured out minimum requirements yet. An article in JAMA found that 2800 IU in the third trimester appeared safe and, while did not reduce the incidence of asthma, corresponded to less severe asthma.

  4. I’m glad to hear managing your daughter’sillness is getting better. I have several cousins with Type 1 and I wonder if the family’s non-fortified goats milK contributed.

    1. Interesting! I have not heard anything about goats milk. I’ve only seen solid research on one possible food-related contributor to Type 1: introducing wheat before 4 months of age. Of course, I didn’t do that with my daughter. Bad genetic luck is probably the main cause 🙁

  5. I’m so sorry to hear about your daughter, and am glad you have identified the issue early. I really feel for you.
    As a woman in early pregnancy (6 weeks), this caused me to sit up and worry that I’m not getting enough vitamin d. My prenatal has 400 IU. I looked around for more information on updated guidelines, and wonder if your recent identification of a serious medical concern for your daughter might be influencing your perception of this strength of evidence? It can be reassuring in a way to find out you did something wrong; that means you can fix it in the future (and that it’s your fault and controlled, not just a combination of factors you don’t control and can’t influence). I feel strongly for you and your beautiful daughter, but I don’t see a lot of evidence here to support this high level of supplementation.
    I don’t see any good scientific credentials for the website. Not all nonprofits are created equal, and the about page lists nothing about any scientific credentials or contributors to the recommendations given. The way the article is written reads as poorly supported, especially when they start recommending specific brands for specious reasons (organic extra virgin olive oil????) that also happen to be corporate sponsors of the non-profit. The ACOG reaffirmed their consensus from 2011 in 2015 which does not recommend 4000 IU. I didn’t go digging into the most recent literature, but a single study from 2011, looking at 2nd and 3rd trimester supplementation only, is not enough evidence for me to change my supplementation without a serious talk with my ob at this time. I might request a vitamin d blood test be taken at my first prenatal, however.
    Best wishes for you, your daughter, and family.

    1. A large meta-analysis (only of observational studies) found a lower risk with supplementation. As have the Finnish studies I cited earlier. There is also a small but consistent birth month effect on autoimmune diseases, high risk of born in the Spring in the Northern hemisphere and highest in the Fall in the Southern. Is there a smoking gun study yet? No. but supplementation up to 4000 IU has been found safe and so there is little downside.

  6. It is worth looking into the connection between cows milk and type 1 diabetes…I have read that in medical literature during college but I never see it discussed anywhere. I’m so sorry about your little one.

    1. This study doesn’t seem to have very good evidence pointing to the cell towers cause diabetes, only that some kids near the cell towers had higher A1Cs but correlation is not causation. Plus there could be other factors like what the cafeteria was serving. And it only looked at type 2 diabetes so I’m not concerned that my own type 1 or your granddaughters is caused by cell towers. I hope she is doing well and taking advantage of the wonderful technology advances that we are blessed to have as diabetics in the 21st century.

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