Insulin's Role in Vascular Damage

Curious what others think of this and if there is any other research to corroborate or refute it. It might explain some of those studies showing higher mortality rates at both low and high A1Cs. It might also validate Bernstein’s approach a bit as he is advocating using small amounts of insulin to achieve control.


I will ask my cardiologist about it at tomorrow’s visit.

1 Like

I didn’t know there was any debate about this. Maybe there is, but I just took it for a fact that insulin is not so hot for cardio.

This morning my cardiologist advised that there has not yet been enough evidence developed regarding the effectiveness Of DPP 4 to be included in The “general guidelines” so, accordingly, it is not regularly prescribed.

I always thought it was the high levels of sugar and not the insulin that causes vascular damage.

1 Like

From the source cited in the post:

This explains why even in an otherwise healthy diabetic with good blood sugar control, insulin treatment may cause insulin resistance in the cells of the vascular system. And this insulin resistance can lead to vascular damage over time.

My history with insulin use involved an over-use of insulin inspired by an over-emphasis of glucose control without regard to insulin dose size. It wasn’t until I started to limit carbs in my diet that I cut daily insulin doses from 80/day to < 30/day. I have severe coronary artery disease as detected by a coronary artery CT scan. This hypothesis seems to explain my experience.

Less insulin, providing in-range glucose levels, is always better than more insulin. I don’t see how any system that fails to limit carbs* can benefit the heart if the conclusions hinted at in this study hold true. It certainly appears that Bernstein was right.

*Or abundantly increase insulin sensitivity by severely limiting fat consumption thereby also limiting total daily insulin use.

1 Like

It may be why for anyone on insulin, T1 or T2, treating any insulin resistance is a good idea. I’m on metformin along with my insulin, as of a few years ago, and that’s been working really well. My TDD is pretty low now, for my weight.

I lowered my insulin resistance by eating a very low fat plant based diet. Even though I eat close to 275 healthy carbs a day I use just 2 or 3 more units of insulin then when eating 30 carbs a day. It makes sense to me that the less insulin the better.

There are some complications like retinopathy and nephropathy that are highly correlated to average bg/A1C as shown by the DCCT a couple decades ago. This was a huge advance at the time.

Heart disease is clearly elevated in diabetics (including long term T1’s) but seems to be only weakly correlated to bg or A1C.

Some diabetes complications, like frozen shoulder, seem to be weakly anticorrelated to A1C.

Frozen shoulder might be better described as a comorbidity than complication, for that very reason, since it’s really unclear if it’s a consequence of diabetes or if there is some shared vulnerability (likely autoimmune), especially since people with autoimmune thyroid disorders also are at higher risk.

Maybe that’s true, to a large extent, for heart disease too?

You might remember me being confused when I was told my hypothyroidism was a complication of my diabetes and if I had better bg control I wouldn’t have hypothyroidism. That sure as heck made me scratch my head. I did some research on the interwebs and found that higher average bg seems to be very weakly correlated with higher (not lower) average thyroid levels (see below)

Correlations really shouldn’t be interpreted like however whoever told you that did. I mean, again, that data could mean so many things. The simplest and most likely explanation to me would be that people with multiple autoimmune disorders would likely have more complete islet cell destruction (we know that even among T1s there’s variability on that front) and also that having other autoimmune problems might increase inflammation and other issues making blood glucose harder to control. It certainly is not proof of a causal link—I’d expect a stronger correlation if so and regardless, a cross-sectional correlation especially is never proof of that.

But yes, it’s hard to say re cardiac disease. My guess is that it caused by diabetes though, whether or not it is caused by poor glycemic control. Could be any of many other things that are part of diabetes but not related to glycemic control, like absence of c-peptides increasing risk.

1 Like