Americans consume more fructose than ever before, yet concerns remain that the sugar, used to sweeten beverages and processed foods, poses health risks. In animals, fructose-rich diets increase the production of fat and promote resistance to the energy-regulating hormone insulin. New research suggests that memory suffers as well, at least in rats.
Neuroscientist Marise B. Parent of Georgia State University and her colleagues fed 11 adolescent rats a diet in which fructose supplied 60 percent of the calories. For 10 other rats, cornstarch took the place of the sweetener. The scientists trained the rats to find a submerged platform in a pool, with the help of surrounding cues.
Two days after the training ended, Parent’s group removed the pool’s platform and recorded where the rats—now adults—swam. Whereas the control group spent most of its time around the platform’s old location, the fructose-fed rats visited this area significantly less often. “They can learn” the platform’s location, Parent notes, “but they just can’t remember it for long periods.”
Another research group has shown in hamsters that insulin resistance can affect the hippocampus, a part of the brain critical for learning and remembering facts and events. Parent’s team is examining whether the hippocampus of the memory-impaired rats became resistant to the hormone. Parent is also interested in how the addition of glucose, another sugar, would affect her results. The body metabolizes fructose and glucose differently, she explains. People tend to consume both sweeteners at the same time, as high-fructose corn syrup (which is most commonly 55 percent fructose and 45 percent glucose) and table sugar (half fructose and half glucose), and glucose aids the body’s absorption of fructose.
Note: This article was originally printed with the title, "Forget the Fructose."
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19 Comments
Add CommentThis is just so counterintuitive to me. I don't get how animals could spend millions of years evolving with fruit being a major component of available food, yet our biochemistry never evolved to metabolize properly.
Reply | Report Abuse | Link to thisI guess the above study just refers to an amount of fructose so high that it causes an overload for the animal's metabolism. Or, is this just a rodent problem because fruit is an abnormal part of their diet?
I would like to see this same study done with primates. From what I understand, some primates like chimps eat almost entirely fruit. Do they suffer from the same fructose consequences? I don't know, but it would be interesting.
[Cerebrl]
Cerebrl - this is not about eating fruit. This is about glucose-fructose, called isoglucose in Europe and comprises any of a group of corn syrups that has undergone enzymatic processing to convert its glucose into fructose.
Reply | Report Abuse | Link to thisAn experiment involving 20 rats. Twenty isn't a very large sample, is it? And besides, they're rats, not humans, which doesn't necessarily mean it's going to produce the same effect. And fructose supplied 60% (60%!) of the calories. That's quite a bit more than in my diet. This certainly may merit more investigation, but does it really merit the publicity it's being given?
Reply | Report Abuse | Link to thishanmeng, the other side of that is that in 10 years if and when the negative health effects are well understood people will be saying, "years ago they did studies showing that fructose was bad for you but no one said anything about it!" Damned if you do, damned if you don't.
Reply | Report Abuse | Link to thisI am a diabetic although borderline, I have noticed the effect in myself. Certain sugars impede my memory like throwing a veil over the hipocampus. Once the sugar has been reduced for example using Gluconorm (a Canadian drug), short term memory is restored. The effect is clearly evident to me that certain sugars affect my short term memory.
Reply | Report Abuse | Link to thisIf Dextrose (Glucose) C6H12O6, and Levulose (Fructose)
Reply | Report Abuse | Link to thisC6H12 O6, combine to form Sucrose (Sugar) C12 H22 O11 are molecularly identical with the only difference being the rotation of the crystal (Dextrose-right, Levulose-left), how is it possible for any cell in the body (Animal or Human) to distinguish and react differently to either one???
Sounds real educated, but the L- and the D- rotation have huge influence on whether or not you body can even use the substance!! The molecule must fit into receptors, and most human receptors a D- oriented, the L-'s can't lock in.
Reply | Report Abuse | Link to thisthe fruits that we and other animals evolved with are nothing like high fructose corn syrup, and even less like a diet of 60% fructose. compare a wild crabapple with a golden delicious sugar bomb, or a modern dessert banana with it's wild starchy cousin. fruits were a very short-time resource; it makes very good sense to eat as much as you can because in a few days it would be rotten. so, the proper metabolic effect of sugar is to stimulate hunger and fat storage. it would not surprise me that there are problems when you make it an everyday large fraction of the diet.
Reply | Report Abuse | Link to thisAre the receptors in rats also D-Oriented?
Reply | Report Abuse | Link to thisWhat about the fact that corn is mostly genetically modified. Who knows what the long term effects will be on humans or rats.
Reply | Report Abuse | Link to thisI am saddened and horrified that science has come so far in recent years, and yet, scientists still have not stopped exploiting animals in lab tests. Testing on animals is inhumane, cruel and unnecessary.
Reply | Report Abuse | Link to this'.. animals differ from humans significantly, making animal drug tests unreliable and dangerous. New research methods, such as computer models, cell cultures, and human studies are more accurate, less expensive, and much more humane.'
Companies that do not test on animals proudly state it on their labels. Send back items that you have from companies that test on animals, and write a letter to the companies explaining why you won't buy their products anymore. For more information on animal testing and a list of companies that do not test on animals, see PETA's Shopping Guide for Caring Consumers and be sure to share it with your friends!'
Learn more at http://www.peta.org/actioncenter/testing.asp
thank you.
Please don't create sensational headlines based on one or two studies. If you want to be convincing, include at least a paragraph on previous studies confirmed by the present one. Twenty rats? Come on.
Reply | Report Abuse | Link to thisRobcon,
Reply | Report Abuse | Link to thisMany many compounds have the formula C6H12O6 and in this case the 3 dimensional structures of D-glucose and D-fructose are very different. d and l in terms of rotation of polarized light is a little different but even in that case the differences can be profound and devastating. I suggest that you search the internet for the story off a drug called thalidomide for a striking example of the different effects of D and L isomers.
Robcon,
Reply | Report Abuse | Link to thisFructose and glucose have very different structures although they can interconvert under the right conditions. Differences in optical rotation may also correlate to profound differences in the response of the human body to a compound. For example use you browser to look up the story of thalidomide, a drug where one form is safe for regular consumption and has therapeutic values while the form that rotates light the other way is something called a teratogen and has devastating effects in a developing fetus.
The assumption that glucose and fructose are only geometrically different (D/L) is wrong. They are different molecules that happen to be made out of the same atoms. Glucose is an aldose, and fructose a ketose. See http://en.wikipedia.org/wiki/Fructose and http://en.wikipedia.org/wiki/Glucose
Reply | Report Abuse | Link to thisAs has been remarked (but unrelated to this issue), the body can digest two molecules completely differently even if they are only mirror image of each other. This is not unlike the difference between the letters b&d or p&q for your eyes: they have the same shape but they can not be rotated to make exactly the same image on your retina. Their "effect" on the body therefore differs.
I want to do f-----g. Would I forget that...
Reply | Report Abuse | Link to thisWhat I do not understand is that since natural corn sugar is Dextrose, how does the process turn it into fructose? Is that what is defined as "invert sugar"? If fructose is grape sugar then why doesn't the grape have the same effect as the high fructose corn sugar on the body? Is it due to concentration?
Reply | Report Abuse | Link to thisIf you're smart people, you'll listen and take heed of the article. Many items on the shelf at the grocery story contain fructose. Stay away from it and notice a change in fat around the belly, lower cholestrol, and a clearer head. The change is subtle, but I stopped the instant drinks and switched to water that allowed me to lose three pounds per month around the waste.
Reply | Report Abuse | Link to this@[Cerebrl] Odd, your question treats "evolution" as fact when your observation actually is questioning the "Theory" of evolution...not a very "cerebral" comment by you... but a demonstration of how brainwashed you are.
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