So polyol pathway is why glucose should always be kept under 140?

[Alex K Chen]

Quote

 

• Question: Why should postprandial blood glucose be kept under 140 milligrams per deciliter?
• Short Answer: When blood glucose rises above 140 mg/dL, this is the approximate point at which it spills into the polyol pathway at a greater-than-normal rate, which represents a suboptimal state of metabolism that is likely to hurt antioxidant status and compromise detoxification pathways as well as the recycling of vitamin K and folate. It must be kept in mind that a healthy person will adapt to glycemic loads they consume regularly. Thus, a one-time spike above 140 mg/dL should never be used to conclude anything whatsoever. Only repeated spikes above this level with repeated consumption of the same glycemic load over several days to several weeks should be used as a cause for concern.

 

is it also bc glucose is converted to fructose in the pathway?
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5975374/

hmm, and my glucose spikes above 140 when I eat many kinds of fruit... which is MORE FRUCTOSE

Edited October 8, 2023 by InquilineKea

[mccoy]

I read the article but it seems to deal explicitly with diabetic conditions, which would entail glycemia above 140 mg/dL after 2 hours of a 75 grams glucose challenge. In a few words, a sustained peak with a large area under the curve.

[IgorF]

Hm, I looked on author's other papers, it seems either "renaissance man" author or science mechanics hijacking network. No credibility to make any conclusions on the topic so complicated.

But that is IMHO of course

Br,

Igor

[IgorF]

Hm,

looked up a bit more for the sake of curiosity.

So called osmotic stress was a questionable hypothesys four decades earlier, e.g.

Quote

The relationship between sugar-induced cataracts according to the
osmotic theory, and cataract formation according to the depletion of
reduced glutathione/oxidative dependent oxidative stress theory is
not entirely clear, as discussed earlier in this chapter, Further, the
potential involvement in cataract formation of abnormalities in the
glycolytic pathway or in the metabolic regulation of glycolysis, and
how these relate to enhanced polyol pathway activity, have not been
fully defined.

(this is a dedicated monograph "The Polyol Paradigm and Complications of Diabetes 1987 Springer-Verlag by Margo Panush Cohen" and is also mentioned as not supported by observations in many articles from the last 5 years.

I tried to address it another way - from cataracts corner just to discover that it looks like:

- high blood sugar is no doubt connected to increased frequency of some types pf cataracts (and less for others)

- 70-80% of t2dm patients with cataracts have this condition for longer than 5 years (usually 10+)

- those who have cataracts with t2dm usually have blood glucose at 200 while those who dont do have 100, thus it is not just concentration, it is multiple queues model rather, with enzymatic activity dependencies, unknown rates and mechanisms of molecules entering/exiting cells and so on

- normally polyol pathway for retinal cells is dealing with 5% of glucose and is being utilized more when anaerobic glycolysis pathway is saturated but

- aldose reductase is the rate limiter for the polyol pathway capacities thus there are opinions that it is not polyol pathway and sorbitol accumulation per se but rather mytochondrial issues, energy disregulation and interconnected occidation stress is rather responsible for the issues (https://www.mdpi.com/2218-1989/11/10/655 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3515641/pdf/eb-2-099.pdf )

I would speculate that this idea makes sense - such things will damage the proteins and this will definitely create consequences, sometimes far going.

So not polyol pathway on its own but rather an unexpected flux is the bad thing itself, later it depends on personal luck (some people are no doubt more prone to develop issues with high blood glucose) and time of exposure. And polyol pathway obserwation as well as enzyme activities are rather signs of increased flux.

 

Br,

Igor