As far as I understand it, diabetes is a disease that is composed of essentially two issues:
- The pancreas' insulin production capabilities
- The body's sensitivity to insulin
and I'm asking a rather basic question whose answer would seem like common sense to most people, that is:
"Does the increased intake of fructose cause increased insulin resistance?"
as in, as you increase this specific sugar's intake, does insulin resistance also go up? to determine this, a scientist would have to measure insulin resistance which I certainly have no idea how to do.
But assuming it is done, and these two variables are appropriately isolated, what kind of correlations have been found between these two??
The background for asking this is that I have known some friends who hopped onto the frugivore fad last year, and their diets are extremely high in sugar from fruit. They still have no sign of diabetes. Although I understand fruits contain many other nutrients and chemicals that may influence insulin resistance, so maybe I should ask
"Does high fructose consumption from fruit cause insulin resistance?" in a separate question.
this question is relevant, and I have noted the reviews and studies mentioned by the answer. The thing is, i'm only interested strictly with the statistical and mechanistic relationships between fructose intake and insulin resistance.
in the first study linked
Consumption of sweet beverages and type 2 diabetes incidence in European adults: results from EPIC-InterAct - Romaguera (and others)
it seems they had very few control variables ?
they just searched for a correlation between sugary drinks and type 2 diabetes in existing patient records. I speak as a layman but that sounds like very weak evidence, I think a method like this should be strictly used to identify potentially worthwhile directions of study, rather than used as evidence.
And in their second source, the journal's review relies rather extensively on rodent studies which i could not be more disinterested in because I have no idea how reliable they are as evidence for humans.
But they did mention this old 1980 human study in which a statistical relationship between fructose intake and insulin resistance was found:
Impaired cellular insulin binding and insulin sensitivity induced by high fructose feeding in normal subjects
but it's an old study, i have not evaluated the methods of measurement they used and they have a sample size of seven people which is much too small though thats not a problem for me as numbers can be corroborated with other studies. Bad study designs are more difficult to corroborate.
I understand there's not many studies of the well controlled design i am looking for on this subject, probably due to ethical concerns but whatever there is, please tell me. thank you