The Wood Frog

Coming from Malaysia I had attempted to mentally prepare for the weather here in NZ. I thought about refusing to wear a jumper in our local cinema (it does get pretty chilly when you’re inside) and perhaps thought about tactically positioning myself in front of the air conditioning in my school classes (these were military grade cooling machines… don’t fact check this one!). You may have established that I am not hardy as my efforts to face to cold were really just my thoughts.

I was fascinated when I stumbled across an article in the New York Times which referenced the March 30 online edition of “Medical Hypotheses”. This, in their words, is journal a devoted to “publishing bold, even radical biomedical theories that are potentially important for the development of medicine.”  

Before I delve into the article’s theory, just a quickie to remind you that Type 1 diabetes is a condition where your blood sugar is too high because your body cannot make a hormone called insulin.

The theory suggests that Type 1 diabetes made its debut 12,000 years in ancestral people in Northern Europe when temperatures fell by 10 F in only a few decades and an ice age practically arrived overnight. Some people froze to death (supported by archaeological evidence). Some people fled south. Some people may have adapted to the extreme cold. This is the belief of Dr Sharon Moalem (an expert in evolutionary medicine at the Mount Sinai School of Medicine in New York) who thinks that “high levels of blood glucose prevent cells and tissues from forming ice crystals.” 

Perhaps I don’t bear much of a resemblance to these olde Northern Europeans form back in the day but rather a little wood frog.

Picture a frog about the size of your big thumb. He’s brown with a few chocolate stripes. This little fella’s ability to tolerate the cold mirrors the metabolic changes seen in a Type 1 diabetic’s body. The frog’s skin freezes up during the winter and in the process, blood glucose is poured into its blood by the liver. The excess glucose completely protects the frog from the cold.  At this point the frog is frozen solid with no movement, heartbeat or circulation. In the Spring the frog thaws out and resumes its existence.  Its diabetes is reversible.

There is still so much more research to be done surrounding the evolutionary theory around supposedly cold tolerant animals like the wood frog and me. 

I will think about Dr Moalem’s theory and the wood frog as winter approaches here in Dunedin.

Glucose upon publishing: 5.5mmol/L
Air temperature upon publishing: (redacted as a friend pointed out to me that this is NO WAY as cold as it’s going to get)