Did you know that more people are diagnosed with diabetes in the colder months of the year? Also, type 1 diabetes is more common in European countries than in African or South American countries. And Finland has the highest rate of type 1 diabetes in the world. What do these things have in common? Yes, it seems there’s a connection between diabetes and cold weather!
Would you believe that in the book Survival of the Sickest, Dr. Sharon Moalem theorizes that type 1 diabetes is actually an evolutionary adaption to the cold?
Image: Blue Sky Studios
By way of explanation, here’s a quick history lesson: Way, way back in prehistoric days, there was a severe drop in temperature called the Younger Dryas, in which the temperature dropped violently in a matter of a few years. While many thousands of people likely froze to death, humans clearly survived. Dr. Moalem theorizes that there might be a genetic trait that helped certain humans withstand the cold. “Just because we can’t survive a true deep freeze doesn’t mean our bodies haven’t evolved in many ways to manage the cold,” Dr. Moalem says. “Not only is your body keenly aware of the danger cold poses, it’s got a whole arsenal of natural defense.”
To get a real quick picture of how this relates to diabetes, Dr. Moalem illustrated his point with a story of ice wine, created in Germany 400 years ago. A German vintner discovered that if he used nearly-frozen grapes to make wine, the wine was incredibly sweet. How did this happen? A grape naturally does two things at the first sign of frost: first, it reduces water to prevent ice crystals from forming inside the grape (which would puncture the delicate membranes of the fruit) and second, it raises the sugar concentration of the water that remains. Why 
raise the sugar concentration? Because sugar is a natural anti-freeze. Ever had a Slurpee? It’s all ice, but never quite freezes because of the massive amount of sugar inside.
A second example is a type of frog in Canada nicknamed the incredible freezing frog, which, after being exposed to near-freezing temperatures, slowly moves water out of its blood and organ cells (to protect it from ice) and at the same time, the frog’s liver dumps massive amounts of glucose into its bloodstream, skyrocketing the blood sugar level.
So, we see two examples in nature of this unique phenomenon, and now the questions is… could humans do this too? In his book, Dr. Moalem suggests that diabetes “may have helped our European ancestors survive the sudden cold of the Younger Dryas.”
OK, but how exactly? Faced with frigid temperatures, Dr. Moalem suggests that our ancestors’ bodies slowed their output of insulin, allowing for their blood sugar to rise. Our ancestors also had something called “brown fat,” which is a type of fat that generates heat as long as it has fuel. Unlike most other tissues, it doesn’t need insulin to bring sugar into its cells. The problem is that most of us don’t have much brown fat anymore, and those who do have enough for this phenomenon to work are those who live in permanently in extreme cold — you know, like igloo dwellers. With our modern technology constantly heating our homes and cars, we’re not exposed to that kind of cold anymore.
But because our ancestors were in constant freezing temperatures, they had lots of brown fat, so their bodies could have simultaneously become insulin resistant in the cold to raise blood sugar (to raise the freezing point of their bodies) while also giving their brown fat plenty of fuel to keep them warm. Essentially, their diabetes functioned as an anti-freeze, and because they had brown fat, their blood sugar levels never reached critical levels and they were able to survive.
Which brings us back to the increase in type 1 diabetics in Finland and why the majority of us are diagnosed between November and February. Could there be a latent evolutionary reaction to the cold weather that puts our body on the diabetes track? It’s been theorized that diabetes is a combination of genetic and environmental factors. Could one of the genetic factors be this adaption from thousands of years ago? And could the environmental factor simply be cold weather? In modern-day humans, unfortunately, if the body slows down its insulin production to increase blood sugar level, there is no brown fat present to use up the blood sugar to keep warm, and that could be where our modern-day diabetes comes from. In theory, of course.
Might seem crazy, but as Dr. Moalem points out, “Evolution is amazing — but it isn’t perfect. Just about every adaptation is a compromise of sorts, an improvement in some circumstances, a liability in others.”
This certainly doesn’t explain every single case of diabetes, but it could help explain many.
In addition to the onset of diabetes, cold weather has anecdotally been shown to raise A1C levels in folks who already have diabetes. As the cold weather sets in, PWDs occasionally complain of a strange phenomenon in which they suddenly need more insulin, and every Spring, as the weather warms up, they suddenly need less. While there could be a variety of reasons for this happens (i.e. holiday food, less exercise), cold weather seems to play a bigger role in our diabetes management than we might think. Or, at least we have something else to blame our wonky BGs on!
What do you think of the Ice Age theory? Were you diagnosed in the winter or do you see an increase in blood sugar during the colder months? Weather-sensitive PWDs, we’d like to hear from you!
Interesting! Thanks for sharing!
[...] This post was mentioned on Twitter by DiabetesMine, diabetesblogs and JCampbell, 2diabetes. 2diabetes said: http://goo.gl/v62Z » Diabetes and the Ice Age – DiabetesMine: the all things diabetes …: Did you know that mor… http://bit.ly/hvXG4d [...]
This is simply fascinating! Thanks for sharing it, Amy!
Interesting theory, but can we connect it with the tendency that till 2020 almost half of Americans will be diagnosed diabetes. We can’t say that our country is so cold. It seems to me that the main cause of diabetes widespread is in culture of nutrition.
I can’t say I notice any change in blood sugars during the cold months of the year. I was diagnosed in November however, and my sister in February. The ice age theory is interesing to say the least.
Personally, the data I’ve read about vitamin D levels affecting type 1 diabetes cases makes more sense. In cold places people also don’t get a lot of sunlight and this lack of vitamin D serves as a risk factor for type 1- or so I’ve heard/read.
For example, I’m originally from Venezuela, just near the equator, and cases of type 1 are very rare there. Doctors have told me that had I stayed in Venezuela, I may not have developed type 1 diabetes. I would have received adequate vitamin D from the sun and ate a very different diet. Can’t really confirm any of this of course, but, it’s something to think about-just like this ice age theory!
Thanks for posting.
I read her book, it was amazing. Not sure if I truly believe the “theory” but some of it makes evolutionary sense.
I was diagnosed in May but I may have had symptoms sooner. Then again, in CNY, it can be Cold in May. Ha.
Not sure I notice “needing” more insulin in colder months, I do notice I need less when it’s hot out though.
I cant say I ever noticed the changes but winter is upon us here in the north east and it might be time to put it to the test and see what happens
I’ve heard this “theory” before and it seems like this “Dr.” has confused Type 1 diabetes (a rapidly fatal autoimmune disease) with Type 2 diabetes (insulin resistance at a cellular level that typically has a mild and slow onset).
There is absolutely no evolutionary advanatge to Type 1 diabetes…it was always a rapidly fatal disease. And it still is if we cannot get our insulin for any reason. Onset is typically in childhood or at a very young age. And onset can be rather quick. I was in a coma within 1-2 weeks of symptoms. It’s not like you can be a “symptomatic carrier” or have a “mild” form. Even in the unlikely event a child with Type 1 diabetes survived to reach puberty, or perhaps developed it in adulthood, it would be unlikely they would be well enough to mate/carry a healthy pregnancy to term to pass on their genes. I just can’t picture all of these hunter gatherer types wasting away and falling into diabetic comas as they procreate.
Not buying it.
Also, we know that Type 1 diabetes, Celiac, Multiple Sclerosis, autoimmune thyroid disease, etc. all share common genetic background and similar pathology. What advantage does the body have to kill off healthy beta cells? Or a healthy thryoid gland? Or the nervous system? There simply is no benefit, with any of these diseases, Type 1 diabetes included. This theory neglects to take into the account the known science of disease pathology. Maybe I’m wrong and they’re right, but that theory seems rather limited.
My personal opinion is that those from Northern Europe (and places populated with NEs) simply share a common genetic background that especially predisposes to certain autoimmune diseases (I.e. Type 1 diabetes, Celiac). The genetic background matters, no matter where you live. Even in the southern US or southern countries, most Type 1 diabetics are white, typically of Northern European ancestory somewhere down the line. That, combined with viruses that tend to be more common in winter months, plus a possible lack of Vitamin D exposure is a more likely explanation. The modern increase in Type 1 diabetes (although minimal compared to the obesity and diet related Type 2 diabetes) may be linked to the increase in vaccinations (immune system stimulus) we give our children during the cold “flu season” months. Your doctor will say there is no evidence to support this, but the simple fact is that no one knows.
Just for the record….Yes, I was diagnosed in Sept….a fall month. But I’ve never noticed the weather affecting my insulin needs. Maybe that’s because they’re always been affected by one unknown thing or another anyways….:)
I have to say, I really agree with what Sarah commented.
Hi, I live in Australia. I was diagnosed at 10 in the middle of our summer 35 C (hot). In Australia the facts are a steady stream are diagnosed, not seasonly. Interesting read though. Yes I do use different amounts of insulin depending on the season.
interesting theory. I’ve certainly been having more trouble keeping my sugars ‘normal’ since things turned really cold around here. But, I don’t normally go out in the cold, I stay in where it’s warm. So, I’m not sure the theory applies to me. lol
Dx in July (onset a few months earlier), but on some levels it’s fun (amidst all the downer news and day-to-day challenges of T1) to read a theory that says T1 is part of an evolved higher survival mechanism!
Well, It seems to me , it’s expected to have BG’s rise during the Colder /winter Months up here in the Midwest, etc. simply because we are alot less Active..Motabolisum slows down , we eat more layaround more, Circulation problems, etc..and alot less Physical activity and Excercise.
takes me about 2 mos into the colder season to adjust, get more Hyper’s and Hypo’s , increase Insulins, reduce I:CR’s etc.. then come Jan things start getting under tight control again.. then come spring reverse it..
I was diagnosed in February, but in Southern California so it wasn’t exactly icy
I do need more insulin in the winter though, but now I am in South Florida so how cold is it really?!
I do believe evolution is involved. Global warming will change things, diet has change things, lifestyle has change things. There are many theroies in discussion. I read Diabetes Rising last year and author pointed out many theroies. They all make sense.
As for me now, I live in the cold of WI now, but I was diagnosed with T1 almost 39 years ago, in sunny South Florida in the month of Feb. So, where do I fit in on these evolution theroies?
Interesting theory, but seems a bit of a stretch. Unless I’m missing something the T1′s would drop dead when the weather warmed up. Removing yourself from the gene pool isn’t a good strategy for any kind of adaptation.
The wine-theory makes sense until you ask a meter. Blood containing 2g gloucose per litre reads 200mg/dl. And 400mg/dl = 4g per litre can buy the ticket for an ER visit.
Dry wine starts about 1.200mg/dl and would not keep anyone from freezing, but there are records of the one or the other type2 still walking on their own into a hospital.
Ice-wines start far beyond that with 70.000mg/dl in the less sweet bottom range reaching up to around 140.000mg/dl in their top range.
So I take the wine-theory for a poor diabetics wine-dream
Yeah, but Nov to Feb does not represent cold to much of the world. It’s only cold during those months in the Nortern hemisphere. In the equator and the soutern hemisphere, it’s hot out, so the correlation bet. months and season is not accurate.
I think it’s the holiday season–much over indulgence may speed the appearance of symptoms and lead to dx. Christmas cookies and lack of excercise will start showing signs of high bs sooner, even thought the dx is inevitable.
Higher insulin needs in winter is I think a result of lower excercise rates. I do think cold weather has a tendency to raise bs, but in non-D’s that just means greater insulin production. In D’s it means higher doses. I don’t think cold leads to an autoimmune reaction that kills off insulin producing cells, although it could lead to insulin resistance.
I was diagnosed with type 1 during November 2006, and am part Danish (my grandfather immigrated to the US from Denmark after WW2). Explains things well, fascinating!
Interesting! It’s compelling, except for the fact that type 1 diabetes has little to do with insulin resistance. And we have little to no insulin production at all, and it seems like their regular (non brown fat) cells would still need SOME glucose (and therefore, some insulin).
But then again, the body is not perfect in its “evolution.” There are theories that sickle cell anemia is so common in people who come from regions susceptible to maleria because someone who has sickle cell cannot catch malaria (the deformed cells aren’t large enough to carry it). So someone with sickle cell in the middle of a maleria epidemic is more likely to survive and pass on their genes than an individual without it. Maybe our ancestors with diabetes survived long enough in the same way, since that brown fat would have absorbed SOME of the glucose and kept them going for a much longer time than a modern day human without insulin treatment.
I wasn’t actually diagnosed in winter, but I’m pretty sue I’m type 1.5 and have no clue what time of year this disease really started for me (but I’m pretty sure it was like 2 years before diagnosis).
I was diagnosed with type 2 diabetes in January 1999. I’ve also noticed that my blood sugar gets higher when it is colder outside. Maybe now I know why… Thanks!