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Preparing for an OGTT

Oldvatr

Expert
Messages
8,453
Type of diabetes
Type 2
Treatment type
Tablets (oral)
Not sure what thread to use for this. It is I think mainly a T2D issue and affects those of us using Low Carb or ketogenic diet, but may also apply to some very low calorie diets such as the 800 diets, and ND
https://pubmed.ncbi.nlm.nih.gov/35108378/

It is a study that shows that those attending an OGTT need to use a high carb diet to prime the system so that the test is valid. This is something we have seen mentioned anecdotally in the Forum, but this is a specific study to prove it.

I note that the glucose tolerance tests used during the Newcsastle diet did not do this priming. However they used an insulin clamp technique, so this may get round the need to pre-prime. I have my doubts,
 
Oldvatr said:
I note that the glucose tolerance tests used during the Newcsastle diet did not do this priming. However they used an insulin clamp technique, so this may get round the need to pre-prime. I have my doubts,
Click to expand...

Insulin clamp technique??? What is that?
 
EllieM said:
Insulin clamp technique??? What is that?
Click to expand...
It is a technique where the glucose is intravenously applied rather than orally. From what I have read in studies that use it the effect is not as severe as the oral hit, so the insulin stimulus is not so strong.
 
The technique is common to mice and other animal studies and works well in the lab, It is uncommon to use it in human studies. My searches only turned up 3 instances of human trials. Newcastle Diet, a chinese study and a study in America. Two of these studies reported problems with interpreting the results when used for T1D diagnosis and c-peptide testing, and i discovered a systemic error when Roy Taylor used it in the ND trials,

It seems that using a drip or infusion bypasses an essential part of the insulin response and that an important enzyme or two is not triggered (amylase?) so possibly introducing error especially when considering the first phase insulin response seen in humans, It may be responsible for some misdiagnosis in TOFI undividuals so the OGTT is perhaps a better test. C- peptide is normally assayed from a blood draw or urine test, so does not use this technique in humans.

Many of us here have an inherent mistrust of 'mice studies'. This is another aspect supporting that view,
 
I thought it was the "gold standard" but too complex for normal insulin measurement.
In human clinical trials, manual glucose clamps as well as the more modern method of automated glucose clamp find common use.
https://en.wikipedia.org/wiki/Glucose_clamp_technique
 
It is a test on beta cell output and the ability of that to clear excess glucose, , but does not measure the complete metabolic pathway that is involved in human diabetes management, It does not aid in diagnosis of T1/T2 for instance. It certainly does not appear to trigger the first insulin response to carbohydrate since this uses mechanisms that are different from the basal second stage. It is not all just about the blood glucose but also the ability to trigger and control other enzymes involved in metabolism.
 

As you are probably aware, I have had quite a few eOGTTs and all of them were fasting, for at least twelve hours prior to the start of the test.
I had thought, that glucose tolerance tests, were only used in pregnancy. As other tests were better for diagnosis and other diagnostic tests for insulin levels and hyperinsulinimia were preferable along with hba1c tests a precursor for diabetes.
Not too keen on mice doing my studies either!

If you don't have insulin resistance and even though your initial insulin response is still poor, though improved,
Why do you still get a weak response?
Why in some cases, a very small amount of carbs, sugars, glucose etc.get a high spike?
And why only certain carbs?

And why, even when your hormones are overcompensating, does your bacteria in you gut have a huge influence on your messaging within your brain and the likelihood of affecting your blood glucose levels?

Does your brain lie to your body?


Best wishes
 
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