Fructose May Motivate People To Seek Out Food | May 11, 2015 Issue - Vol. 93 Issue 19 | Chemical & Engineering News
Volume 93 Issue 19 | p. 6 | News of The Week
Issue Date: May 11, 2015 | Web Date: May 7, 2015

Fructose May Motivate People To Seek Out Food

Neuroscience: Compared with glucose, fructose activates brain regions that enhance the psychological reward of eating
Department: Science & Technology
News Channels: Biological SCENE
Keywords: fructose, sugar, diet, obesity, neuroscience
Foods such as sodas have increased our consumption of fructose.
Credit: Shutterstock
People get the majority of their fructose from foods such as sodas that contain added sweeteners.
Foods such as sodas have increased our consumption of fructose.
Credit: Shutterstock

The sugars we eat may influence how our brains decide whether we should put our forks down or go back for second helpings, according to a new study. The findings suggest that fructose—a sugar found in fruits as well as in sweetened products such as soda—does not trigger the brain’s satiation signal in the same way as glucose, a sugar that’s the main fuel source for most of our bodies’ cells. Fructose may instead activate pathways that increase the appeal of food.

In 2013, Kathleen A. Page of the University of Southern California and colleagues found that fructose activates the hypothalamus, a part of our brains that regulates food intake (J. Am. Med. Assoc., DOI: 10.1001/jama.2012.116975). On the other hand, glucose, which packs the same caloric punch as fructose, suppresses activity and leads to a feeling of being full.

In the new study, Page’s team looked at effects in brain areas that process rewards. They had people drink cherry-flavored water sweetened with either fructose or glucose, and then they monitored the subjects’ brain activity inside a functional magnetic resonance imaging (fMRI) machine while presenting them with pictures of food. When people drank fructose, the food images produced more activity in the orbitofrontal cortex than when they consumed glucose. Activity in this brain region has been linked to increased motivation to seek out rewards, including food or drugs.

Before allowing the subjects to leave the fMRI machine, the researchers offered them the choice of either receiving a snack that day or money a month later. People who had just consumed fructose were more likely to forgo the delayed payday in favor of food compared with those who had just received glucose (Proc. Natl. Acad. Sci. USA 2015, DOI: 10.1073/pnas.1503358112).

One strength of the study is the combination of this decision-making test with the brain imaging data, says Peter J. Havel, a professor of nutrition at the University of California, Davis, who was not involved with the study. “It’s connecting what’s happening in the brain with what people are actually doing.”

The study, Havel says, is limited to short-term effects of fructose versus glucose. He proposes longer studies that follow how much people actually eat outside the lab after consuming the two sugars.

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Palangpon (May 7, 2015 4:53 AM)
The structure of fructose in the post is incorrect.
David Shobe (May 14, 2015 6:27 PM)
Actually, what's shown here is one form of fructose. Sugars often have many interconvertable isomers. (The "isomeric forms of fructose" sidebar on Wikipedia shows the major forms in solution, but not all possible forms. You're right in a sense, though, since the major solution form has the CH2OH group on the "top" side).
Michael Torrice (May 18, 2015 11:48 AM)
Thank you for reading. Fructose can have a few different isomers--both five-membered and six-membered ring isomers--including the one pictured with this story:

Dr. R. H. Fish (May 13, 2015 1:57 PM)
What about the fact that HC Fructose leads to diabetes in school children, which is also important to correct.
Robert Buntrock (May 21, 2015 10:02 PM)
That study used HFCS sweetened drinks. What was only tangentially alluded was the same effects could be noted with any sugar based sweetened drink (I just wrote a letter to the author and editor of that paper). HFCS is 55/45 fructose/glucose and sucrose (table sugar) is 50/50. "High fructose" is misleading since HFCS is quite similar to sucrose and less is needed to achieve the same sweetness level, resulting in less calories. Your response is typical of the reason that I informed the author that the tile of the paper was misleading.
T.J. Burnett, Ph.D (May 15, 2015 1:45 PM)
The study design does not correct for the effect of the sweetness of the three drinks. Some recent work suggests that artificial sweetners can influence appetite, too. I would be interested to see if others agree.
TEST FOR ASM (May 18, 2015 2:02 PM)
Looks like an interesting article by Whitesides, I'll have to access it at the library.

I was not at the Denver meeting so unfortunately missed your presentation. The other sciences may be perceived as â€oesexier― than chemistry but I guess we’ll have to emphasize the chemistry aspects of the â€oesexy’ subjects you cite like the formation of the elements and even compounds in stars and the chemistry of the origins of life (some exciting recent developments linked with iatrochemistry). Admittedly the Big Bang and black holes are more purely astrophysics. You're correct that the public only tends to perceive chemistry to be â€oesexy― when chemophobia is presented, especially by Vani Hari (aka the Food Babe).

Re Kekule and the structure and bonding of benzene the best description I've read (and reviewed) is an Image & Reality: Kekule, Kopp, and the Scientific Imagination; (Alan J. Rocke, Univ. of Chicago Press, 2010) which also describes the history and development of the determination of chemical structures in general. Kekule's (in)famous dream of benzene bonding is more accurately described, especially in the original, as an awake reverie or daydream.

Bob Buntrock
Orono, ME
Robert Buntrock (May 21, 2015 9:59 PM)
This synopsis and the article do not acknowledge that the fructose/glucose ratio of HFCS is 55/45 and sucrose is 50/50. The research should also be performed with sucrose flavored drinks. I communicated this to the authors of the original paper and they agreed. However, there was no funding for that additional research but when funding is procured, they will run the comparison.

HFCS is so named because the percentage of fructose in corn syrup is increased from about 25% to 55%, hence "high fructose".

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