Does T1D affect my brainpower?

Hi All

Diagnosed few years ago with insulin dependent T1D. Does T1D affect your brainpower or make you less sharp and quick? I am not sure if it’s me thinking that or is that is actually the case?

I don’t mean during a low I am asking in general?


Well, I am not T1DM but T2DM - I don’t know about long term brain fog from diabetes, but when I am not in tight control - I don’t think right.

It is especially true if running above 180mg/dl. When I am low, I can have an emotional storm, mostly anger and don’t get between me and food - hangry some call it.

I have gotten as low as 40mg/dl and dropping that caused mental issues.

I have always assumed that since the brain is the largest consumer of glucose that BG out of range is going to affect brain function.

Did a search on the subject and there are lots of studies showing a correlation between type 1 DM and cognitive decline. For some reason there are differences in the cognitive decline of type 1 and type 2.


You personally, maybe, but in general, there are indications it might. I assume you did some googling, and you will see studies showing lower brain volume, but not lower IQ, or slower reflexes in older T1D.

That said, I would wonder why you are concerned. Understandably, any T1D might have concerns about effects, particularly as we age. At 62, I still get noticed for my intelligence as compared to others in the tech area I work in, but even then, I still wonder about future effects on my intellect. I do think some my some reflexes are slower, but much of that is simply age. On the other hand, some of us might overly fret if we don’t remember something, where we have some odd ‘bare patch’ that might be simply normal.

If there is such a likelihood of greater brain loss, it would mean we should try even harder to avoid it. Some of the following might simply be correlations, not something that can help, but to the best of my knowledge, the usuals:

  • Good glucose control
  • Avoiding severe hypoglycemia, in particular
  • Exercise
  • Mediterranean diet (or similar)
  • No smoking
  • Good relationships
  • Intellectual pursuits
  • Learning new…

There are others, but it’s senseless to worry, but useful to improve.

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At 72 and after having been a type 1 for 64 yrs, I haven’t noticed much change. I don’t think my IQ has changed, but I do search for words more often. I think that is due to aging more than anything else. I do try to follow all of the suggestions that James mentioned. Staying in excellent control takes a lot of thinking and constant decisions have to be made, so that helps to keep my brain working well.


Probably true, but keep in mind that we ALL also have more things these days vying for our attention. With our perception of events being pulled in 20 directions as once, I wonder how any of us can function as well as we used to do! James and you both are correct: If you take care of yourself and continue to exercise your brain, your body and brain will serve you well.


Certainly the preservatives used in insulin can have an adverse affect on one’s system in various ways.


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On and off, yeah.

I wouldn’t worry abiut it because that will stress you. Any kind of chronic stress can negatively affect all kinds of performance unless you learn how to handle it. PWT1D are known to have generally impaired quality of sleep, which directly effects perfomance. The simplest way to hande it is to use the best tech avalable and learn how to get your BG under, not good, but great control.

Ignore the naysayers. There’s a learning curve, but it isn’t as hard as what you’ve already learned to do well and you have time on your side all the way to the end. All you have to do is want to do it, keep learning a little more every day, and not brood over mistakes.

I do know that the brain uses ~25% of our glucose when resting, and I believe that when it doesn’t get enough, that’s what causes/triggers the symptoms of hypo.

I know that if I let myself get below 70mg/dL I get short tempered, and below 50 mg/dL it get very hard for me to make decisions. Fortunately I haven’t been hypo since I’d started using a CGM, wish I’d started sooner. .

Hyperglycemia, on the other hand, has never been a problem for me, at least not short term. I used to handle emergencies by chugging a bottle of regular cola. That could keep me going for hours of restoring servers that crashed without stopping except for bathroom breaks. I wouldn’t recommend this to anyone or do myself it today, but it worked for me back then.

After 30 years of T1D, I was a +50 YO in IT, self-taught and directly competing with 20-30 YOs, and outperforming them. Few of them were enthusiastic about it. If T1D effected my “brainpower” negatively, it would be a problem for me to not have it. Being slightly smarter than average in some ways is hard enough to handle. Being a harder worker is just as bad. Being even more of an outlier would have made it harder for me to get along with people than it did.

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I don’t think it makes you less intelligent, but having low blood sugar can impact how your brain works. I remember a long time ago when I was still in school, I was a part-time bank teller. I was having a low and counting became an issue. Counting is a huge deal when you are a teller.

I’m much older now and don’t get lows that bad anymore because I wear a CGM, but hypoglycemia does negatively impact how quick you are.