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False high A1C on a carnivore (or very low carb) diet

B

Bcgirl

Well-Known Member
Messages
524
Type of diabetes
Type 3c
Treatment type
Diet only
I’ve seen it mentioned quite a few times, that carnivores can have false elevated A1C levels. The theory is that carnivores have longer lived red blood cells and they are therefore exposed to blood sugar over a longer period making them more likely to be glycated.
i would love to hear some experiences!
personally I just finished a three month dairy free carnivore journey (After many years of very low carb). I wore a Cgm the entire time (at quite an hefty cost) and quite honestly my blood sugars were pretty good. My 90 day average was 5.9 and my estimated gmi was also 5.9% (this is kind of like A1C). When I tested last week my A1C was 6.2 (44j, down from 6.5(48). That was way higher than I expected based on my readings. My blood sugar NEVER went above eight and eight would be a shocking number…it just didn’t happen. I don’t go low, generally a low five would be it.
so, with another blood test three months away I am trying an experiment….get rid of those old red blood cells. I will be donating blood on Tuesday. I would only try this three months out as I don’t want a false low as I imagine it would be if you donated closer to your test day. What I want is an accurate number just for my own peace of mind.
I am continuing carnivore but with no carb dairy (aged cheese) and an occasional single strawberry as they are in season.

would love to have some nerdy science talk…..
 
I can't offer useful information but I too am interested in what others can add to this.
 
Ok, so today I donated blood….i am a small person, just meeting the weight requirement to donate and it didn’t go as well as I had hoped. I was careful to eat and be well hydrated but after donation I felt nauseated. They were so good, cooling me down, raising my feet…darn! they wanted me to eat, but everything they had was carbs. They were insistent so I figured salt was better than sugar and ate some potato chips. Omg, blood sugar was at 10.6 two hours later….I am so mad! I just can’t handle any carbs…. Doesn’t help that it’s 40 flipping degrees either…
now I’m hoping this little experiment works….and next time I donate, and I will, I’m bringing some salty snacks (i did bring a few nuts, but they weren’t salted). Maybe cooked bacon slices!
 
They would have wanted you to eat something sweet to raise the levels deliberately after feeling feint. Far more important for the brain than a raise to 10. A perfectly acceptable level for non diabetics on a daily basis. Salty bacon would not do that.
 
I’ve actually never seen this mentioned and would be interested to find out more about the claims too.

I do know that certain forms of anemia and some other red blood cell affected conditions can cause false hba1c readings. Could any of these apply to you?

Eg If you have iron deficiency (even if not actually anemic) giving blood would only make this worse. When you donate they check haemoglobin for actual anemia but not ferritin for iron deficiency without anemia. And the lab reference range for ferritin reflects 95% of the typically seen levels not the optimal levels for good health (often given as 80-100 ish when it is actually given). The lower end (around 10-13) is also well below the cut off for the definition of absolute iron deficiency (below 30) as per NICE and many other organisations Creating a conflict between the two definitions. Maybe see if you can get a ferritin test before donating and checking hba1c agaIn
 
Are you prescribed any BG lowering meds?

Looks like on your profile “diet only?”

Unfortunately, carbs would be what you need to treat a low…
Depends on how fast you’re dropping? “Potato chips” (or crisps in the UK) could do the job for me if caused by basal..
 
@Bcgirl I must admit I have not heard of carnivores having falsely elevated HbA1c levels. I too would be interested to know if anyone else has heard of this.
Just a thought, with us being under a heat warning here, do you think dehydration may have played a role in your elevated A1c results? I know the BC interior can get up there in temperature, but 40c is unpleasant.
 
@Bcgirl a note of caution.
I wouldn't rely on a CGM to give you an accurate predicted HbA1c.
For some people they are reasonably accurate.
For me, my Libre 2 predicts a much lower HbA1c than I actually get from a blood test.

A good while back I was going to pursue this with Abbott by submitting finger prick blood tests alongside my CGM readings but this all fell by the wayside when my BG monitor stopped talking to the Abbott site.
I now have a new meter so hopefully I can pick this up, but differences between interstitial fluid and venous blood, and individual differences in longevity of red blood cells, means that you can't 100% rely on the CGM results to give you an accurate HbA1c.

This could tie in with carnivores having longer lived red blood cells (I haven't eaten pure carnivore yet) or it could just be an artefact of the different methods of measuring noted above. Or just natural variation.
 
I’ll quickly answer a few questions and then see if I can’t find some info.
please, I’m not saying that this is true, just a theory that I’m willing to test on myself.

my hemoglobin is perfect, had blood tests a week and and also they tested me on site.

i used to use libre 2 and it was garbage. Switched to Dexcom 7 and it’s pretty darn accurate and I always checked with blood pricks. It’s easily calibrated.

yes… the heat. My A1C was done before the big heat wave so it should be fine.

i am not on blood pressure meds, have a good normal blood pressure but it was affected yesterday. A few hours after I got home it was very close to low….98 over 59…..likely why I was lightheaded. I’m back to normal this morning.

salty food was recommended, not sugar. The salt is to keep your blood pressure high. My body is very efficient at gluconeogenisis and the ****** carbs in the chips converted to sugar in seconds….hence my high reading (Very high for me as I rarely get above 7)

because I am small framed…5’7” and 112 pounds I imagine taking a full donation of blood would affect me differently than a larger person…they naturally have more blood. Next time I go, and I will, I’ll be salted up and fully hydrated. I’ll bring my zero carb salty snack too.
my size was noticed by the on-site nurses and they mentioned it could be a problem.
 
I love dr Paul Mason….have a listen to this whole episode, but for the theory that I mentioned start at the 4 minute mark
 
I just got my blood tested. I had high Hemoglobin A1c, and I'm on a keto diet so am in ketosis. I really think there is something to this.
 
No one important said:
I just got my blood tested. I had high Hemoglobin A1c, and I'm on a keto diet so am in ketosis. I really think there is something to this.
Click to expand...
Hi @No one important , welcome to the forum.
How high was your hba1c, and have you done some fingerprick testing to see what your blood glucose actually is?

Being in ketosis doesn't mean you can't have diabetes and high BG.
 
There are some conditions that cause false hba1c, mostly those relating to the blood and red cells eg some forms of anemia. Personally not heard of carnivore doing it though.
 
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