The Diabetes Coffee Effect

The Diabetes Coffee Effect

Maybe it’s a symptom of my longtime type 1 but I’ve never enjoyed “polluting” my coffee with cream milk sugar or artificial sweetener. Uck… no thanks! I’m a guy who likes his coffee black which is fortunate in that I’m not tempted to add anything in my coffee that may boost my blood sugars unnecessarily.
{Fellow Coffee Lovers: If you’re in need of your own cup or warm up here’s a good chance — go on I’ll wait…}
A few years ago when I was going through a diligent diabetes monitoring phase I wondered about coffee. So I paid a bit more attention and noticed that it seemed to raising my blood sugars some in the morning hours. But that may have been caused also by Dawn Phenomenon making my glucose numbers rise anyhow and/or by inaccurate carb-counting the night before.
Doing some basal testing it eventually became clear that my sugars were rising on a “typical day ” which always included mass coffee consumption. I wasn’t sure if caffeine was causing the problem but decided to increase my basal rates by about 50% for two or three hours in the mornings and got to the point where I could maintain a flat line if all else was in line (IF being the operative word here!). There were also times I’d take a a couple extra units and spread them out over a few hours and that also seemed to work.
But what if I wasn’t using my insulin pump?
During one of my insulin pump hiatuses was actually the first time I noticed my blood sugars were definitely going up more when I consumed black coffee but didn’t compensate with insulin. A couple of units of insulin mid-morning would usually do the trick.
Good stuff to know for any type 1 coffee lover!

My Great Coffee Experiment of 2015
Now recently I’ve been more closely tracking this Coffee Effect as it relates to my blood sugars.
With the new year my wife and I have been working to eat better and live healthier — especially since Feb. 1 marked my 36th birthday so it’s long past the point where I should be concentrating on this…
For the past of couple weeks I got serious about it cutting down on coffee consumption to make tracking easier. And after about 10 days of CGM data analysis and coffee trial and error I concluded my blood sugars rise as much as 50 points on a given day due to coffee.
Magically I didn’t fall over dead from coffee withdrawal (pretty amazing to me!) And rather than feel pressured to write everything down I snapped a whole bunch of photos with this one capturing what I saw as a trend during this experiment:
A couple of days without any coffee while hooked up to my insulin pump: As far as I could tell all other factors that can mess with BGs aside I definitely didn’t rise as much as I usually do when drinking coffee.
A few days with coffee while pumping (two with higher basal rate; one with “non-coffee” basal): This pic shows how my glucose fared when the basal rates had coffee factored in: pretty well!
Two days without coffee and no pump just injections: Wow – I didn’t see any of the typical mid-to-late morning BG spikes.
Two days with coffee on injections (one with bolus one without): Yep saw a boost when there wasn’t any insulin to combat the caffeine. Of course there may have also been some Dawn Phenom at play but I don’t know for sure…
Obviously it’s pretty near impossible to control for every other factor and be able to say with 100% certainty that stress the weather or the dog’s tail-wagging didn’t play into my BG shifts. But for the most part I think these 10 days gave me a good idea of what the Coffee Effect does to me. Caffeine makes me go up not dramatically but significantly.
No this changes nothing about my coffee-drinking habits and just reinforces what I was pretty certain of before: that I need a little insulin boost when coffee’s at play. And I’d much rather calculate that into my basal rates than take an extra bolus by shot if possible.
With everything related to diabetes Your Diabetes May Vary and medical opinions do too; some experts claim caffeine does not affect blood sugar but others state with authority that “caffeine makes it hard for people with diabetes to control their blood sugar.”
That’s why I think it’s important for us PWDs (people with diabetes) to do these real-world experiments and share our results. And while we’re waiting we can grab another cup before reading through the stories PWDs share.
Sounds like healthy coffee and conversation to me!

Mike Hoskins is Managing Editor of DiabetesMine. He was diagnosed with type 1 diabetes at age five in 1984 and his mom was also diagnosed with T1D at the same young age. He wrote for various daily weekly and specialty publications before joining DiabetesMine. Mike lives in Southeast Michigan with his wife Suzi and their black lab Riley.