Monday, October 20, 2008

Fructose and leptin

Just a quickie. This was forwarded to me by Gary. It just keeps bringing home to me that leptin is very interesting stuff and fructose is very nasty stuff.



gunther gatherer said...

I also find it interesting that the researchers found a direct relationship between high fructose diet and hi trigs, even without noticeable weight gain or any other problems.

donny said...

This one makes me wonder--they've found leptin injection ineffective in most cases of obesity. Maybe it'd work better if any issues with high triglycerides, fructose-induced or other, were addressed first?

donny said...

This article from Science Daily March 2007 agrees about fructose inducing leptin resistance.

This quote

"Poorly balanced diets and the lack of physical exercise are key factors in the increase of obesity and other metabolic diseases in modern societies."

is interesting. In an article about a study clearly supporting the idea that physiology is pulling psychology along behind it, they end with the usual "obese people are lazy and gluttonous", but gluttonous is replaced by "poorly balanced diets". Which is far less disagreeable.

A Professor Laguna in the article stresses that this doesn't mean that fruit is bad for you, just fructose. If they're just glomming on to fructose's effect on leptin now, I wonder what the odds are that they've even done any studies on just feeding rats fruit?

Maybe this is dancing with the devil, but Lyle McDonald suggests high carbohydrate refeeds to recover leptin on all kind of diets, whether low carb or not. These guys documented excess buildup of leptin when feeding rats extra fructose, but not glucose. I'd never consider pure crystal fructose, but I've been known to dive headfirst into the odd watermelon. (The devil here's watermelon, not Lyle.)

JohnN said...

"...but I've been known to dive headfirst into the odd watermelon."
Somehow this statement reminds me of a blurb on Science Daily a few months ago on the Viagra-like effect on consuming watermelon.

donny said...

I reread the article about fructose. I guess the leptin might build up but not do any good anyhow.

Johnn, I hated that article. Makes it hard to eat watermelon in polite company.

ItsTheWooo said...

It's not really appropriate to say that fructose causes leptin resistance... MRE has written that triglycerides prevent leptin from crossing the BBB (where it exerts effects on satiety). So fructose is only a problem if it leads to high triglycerides, which may not be the case (if you're on a LC diet fructose is less of a problem 'cuz it replenishes triglycerides before making your liver into a fat factory).

If they injected the leptin into the brain's ventricles of the people with high triglycerides, I it probably would work as well as it does for people without high triglycerides.

ItsTheWooo said...

Graaah I meant to say replenishes glycogen (not triglycerides).

Peter said...

Heh hee ItsTheWoo,

Would you expect a nutritional researcher to read Dr Eades' blog (or have read the literature in their chosen field....). Actually, to be fair, the literature is pretty large. Also I'm not sure if fructose converts to glucose as a glycogen replacer. It generally is converted in the liver to fructose 1 phosphate then glyceraldehyde 3 phosphate which drops down the glycolysis pathway (Peter copies sections from "crash course in metabolism"). Could inhibit glycogenolysis by increased ATP levels.

But it's clear there must be a second messenger (trigs?) as remarkably little fructose gets anywhere near the brain.


Hmmm, but the liver talks to the brain through the vagus. Your IC injection idea sounds more worth trying. Not volunteering. I'll settle for low trigs!

hopeful geranium said...

The other day, out of curiosity, I went into an Organic Health Food store (in Dunedin, N.Z.). I found the following products in both: 500gm bags of pure Fructose; a bulk bin of purified Gluten; and bulk Soy Bean oil.
The Dietary Triad of Doom, in other words.
Maybe we should be protesting outside such places?
"Wheat is Murder".