Was tipped off to the following article:
https://www.nature.com/articles/d41586-021-02195-1#:~:text=18%20August%202021-,Fructose%20in%20the%20diet%20expands%20the%20surface%20of%20the%20gut,dietary%20nutrients%20and%20weight%20gain
The contention is increased fructose consumption leads to increased absorption of stuff in the gut (nutrients + other things) which triggers increased risks of certain cancers and obesity. I know there has been a lot of investigation on this topic.
I wonder if that increased absorption is something we can benefit from? The report indicates the this extra absorbability allows both nutrients and the resident microbiotics more access to the bloodstream and the later triggers an inflammatory liver response. Also, I only saw “HFCS” in the article and (I did not read very deeply but took a quick skim of it, I’ll read before I rack out this evening) did not see straight up regular fructose in fruit or powdered form. I suspect that is significant.
I wonder if this applies to protein absorption too? My guess is yes it would but of course that is just a guess and would require another study.
Is there benefit here? Or is that yet to be determined?
1 Like
There is definitely some interesting stuff in that article! First of all, it’s a mouse model…so all the usual caveats apply.
So fructose keeps cells on the villi alive longer…so as new cells are produced at the base and migrate up to the tip the villi grow longer thus increasing overall surface area. Longer villi–>more surface area–>greater absorption. Although I guess greater absorption of fructose, too, as GLUT5 up-regulates…probably conferring liver protections by digesting fructose before it can escape to 1st pass absorption by the liver. But, whatever.
Well, fructose is fructose in the gut. The article did link research from Rabinowitz’ lab where they explicitly state that 1g/kg is kind of the overload point. So, that is a lot! Like, three pepsi’s? Or 10 cups of grapes. It’s a lot. 
And, anyhow, quite arbitrary if the research in the Nature article holds up.
For sure, though, this article is some very tangible evidence that what you eat can make a difference without regard to the absolute energy content of the food. At least, if you’re a mouse.
2 Likes
Strongly doubt there’s a benefit to target here. Gut permeability is not a terribly great thing since you can’t select for the “nutrients” part and avoid the bad parts (eg, lipopolysaccarides aka endotoxin; or maybe glutens?). Its one thing to upregulate a transporter; its another to break down tight-junctions and just have whatever crossing into your circulation. I wonder if this is partly a mechanism for varying intake tolerance across people.
1 Like
Yes pretty much the impression I have as well. I do recall seeing a statement this uptick in absorption allows gut resident bacteria to infiltrate into the bloodstream and the researcher that tipped me off to this article said that while my initial thoughts are understandable they don’t pan out. I still think this is a thing to watch however it all turns out.
I also recall a passage suggesting/hinting at a more direct carcinogenic effect here too. At least more direct than causing obesity.