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High Fructose Corn Syrup Causes Bigger Weight Gain In Rats
krou writes "In an experiment conducted by a Princeton University team, 'Rats with access to high-fructose corn syrup gained significantly more weight than those with access to table sugar, even when their overall caloric intake was the same.' Long-term consumption also 'led to abnormal increases in body fat, especially in the abdomen, and a rise in circulating blood fats called triglycerides.' Psychology professor Bart Hoebel commented that 'When rats are drinking high-fructose corn syrup at levels well below those in soda pop, they're becoming obese — every single one, across the board. Even when rats are fed a high-fat diet, you don't see this; they don't all gain extra weight.'"
Glad to oblige! This story was posted on Science Daily yesterday. They included the following:
Editor's Note: In response to the above-mentioned study, The Corn Refiners Association issued a statement titled "Gross Errors in Princeton Animal Study on Obesity and High Fructose Corn Syrup: Research in Humans Discredits Princeton Study" (http://www.corn.org/princeton-hfcs-study-errors.html). This link is provided for information only -- no editorial endorsement is implied.
Sorry, but that blog seems to be a wee bit on the crackpot side of things. The body does not really care how the fructose is administered - when it arrives in the intestine, it is in solution anyway, so no difference whether it comes crystalline or as HFCS. The effect should be the same. The problems that are pointed at in that post are probably true, however. Fructose triggers a lower insulin response than glucose, so the hunger persists despite caloric intake. Also, fructose is metabolized mostly, if not only, in the liver, which causes stress on the organ.
Usual table sugar - sucrose - is a disaccharide made from one molecule of fructose and one of glucose. The glucose part triggers the insulin production, which signals that you have taken in calories. So, if you use normal sugar instead of HFCS, your body knows that you got energy way faster. That seems to be the main obesity mechanism associated with HFCS.
Ubi solitudinem faciunt, pacem appellant.
Arstechnica.com covered this same study the other day. Their writeup is better than mine would be so why don't you read their article? http://arstechnica.com/science/news/2010/03/does-high-fructose-corn-syrup-make-you-fatter.ars
The abridged version of the abridged version is that this study does not conclusively prove much of anything.
It is not enough to succeed, others must fail. - Gore Vidal
I am a (stressed out) med student studying for a GI physiology exam. Sugars must be broken down in the small intestine to monosaccharides to be absorbed, so sucrose becomes glucose and fructose, lactose (if you're not lactose intolerant) breaks down to glucose and galactose. Glucose and galactose are absorbed via co-transport with sodium via transport proteins. This requires a standing Na+ gradient in the cell, maintained by the Na-K pump, which requires the expenditure of energy. Fructose on the other hand enters the cell by simple facilitated diffusion through the GLUT-5 protein, meaning its transport out of the intestinal lumen requires no energy expenditure. Biochemically it it can enter the glycolytic cycle and is rapidly metabolized in much the same way as glucose.
Sugar in general should be avoided. Fructose, which is the bad half of sugar and HFCS, is the culprit. It can only be processed by the liver, and during processing it wreaks havoc on the body's systems for controlling hunger, satiation, insulin, etc.
Take the time to watch this talk by Robert H. Lustig, MD, UCSF Professor of Pediatrics in the Division of Endocrinology. It might save your life (by extending your life).
Make your own ketchup - it's REALLY easy, actually - just google for recipes. It's pretty much just tomato, vinegar, onion powder, and sugar (salt and oil optional), plus perhaps a little starch to get the right texture. Buy canned tomatoes in bulk, throw a can or so of them into a blender with everything else, cook and stir until smooth and even, then put it into a container in the fridge. Cleanup is just running water over everything. 15 minutes work for as much as you want to make. Incidentally, a little more sugar/oil/vinegar makes it into french dressing.
There you go - good ketchup without HFCS.
Ryan Fenton
HFCF is fructose and sucrose. Fructose is absorbed by the small intestine. Sucrose (table sugar) is broken down in the stomach and small intestine into 1 glucose molecule and 1 fructose molecule, which are then both absorbed by the small intestine. So, either way you get fructose, big deal, right? That's the conventional wisdom.
But lets look further. If you eat 1 tablespoon of HCFC 55 (equal in sweetness to 1 tablespoon sucrose), you get .55 tablespoons of fructose and .45 tablespoons of sucrose. That sucrose is turned into half fructose and half glucose before entering the bloodstream. So in reality you ate .775 tablespoons of fructose and .225 tablespoons of glucose. This is significantly more fructose than if you had eaten 1 tablespoon of sucrose. And if you're consuming sugar water (as in the study) or lots and lots of soda, you're consuming far more than a tablespoon.
Of course your claim that it's "absorbed ... in the same way that beer and alcohol is. In the liver" isn't quite correct. They're all absorbed by the small intestine, but it's true they are metabolized by the liver, albeit in completely different ways. What's might be important about the liver, though, is that it's not regulated by insulin. While glucose can be metabolized by any of the bodies cells, insulin regulates blood glucose levels. Fructose is only processed by the liver and is indifferent to insulin levels. So (in a layman's, but more detailed explanation) when you eat that 1 tablespoon of table sugar, you get half a tablespoon of unregulated sugar and half regulated. Eat the HFCF55 and most of the sugar is unregulated.
As an aside, honey is almost identical in composition to HFCF55, so if you meet any holistics bemoaning HFCF and championing honey, you can tell them to screw off.
Fructose is the culprit. But there are differences. Pure fructose is hard to absorb. Fructose in fruit is released only slowly. Both are probably OK. Fructose in sucrose needs to be split off before being absorbed, which seems to limit its rate; at normal sucrose concentrations, the fructose is also absorbed more slowly than the glucose.
HFCS is the worst of the bunch: it doesn't need to be split, and the 1:1 fructose/glucose ratio is ideal for rapid absorption, and both sugars peak simultaneously, putting a large load on the liver.
So, you're fine with moderate sucrose consumption (disaccharides) and eating fruit till you burst (fructose+fiber). Pure fructose is iffy. And HFCS is a no-no.