Atmospheric methane levels increased over geological formations in Northern Siberia following a heat wave in 2020, suggesting that permafrost thaw releases methane from reservoirs.
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Edited by Todd F. Heatherton, Dartmouth College, Hanover, NH, and accepted by the Editorial Board April 8, 2015 (received for review February 18, 2015)
Significance
Fructose compared with glucose may be a weaker suppressor of appetite. Here we sought to determine the effects of fructose versus glucose on brain, hormone, and appetitive responses to food cues and food-approach behavior. We show that the ingestion of fructose compared with glucose resulted in smaller increases in plasma insulin levels and greater brain responses to food cues in the visual cortex and left orbital frontal cortex. Ingestion of fructose versus glucose also led to greater hunger and desire for food and a greater willingness to give up long-term monetary rewards to obtain immediate high-calorie foods. These findings suggest that ingestion of fructose relative to glucose activates brain regions involved in attention and reward processing and may promote feeding behavior.
Abstract
Prior studies suggest that fructose compared with glucose may be a weaker suppressor of appetite, and neuroimaging research shows that food cues trigger greater brain reward responses in a fasted relative to a fed state. We sought to determine the effects of ingesting fructose versus glucose on brain, hormone, and appetitive responses to food cues and food-approach behavior. Twenty-four healthy volunteers underwent two functional magnetic resonance imaging (fMRI) sessions with ingestion of either fructose or glucose in a double-blinded, random-order cross-over design. fMRI was performed while participants viewed images of high-calorie foods and nonfood items using a block design. After each block, participants rated hunger and desire for food. Participants also performed a decision task in which they chose between immediate food rewards and delayed monetary bonuses. Hormones were measured at baseline and 30 and 60 min after drink ingestion. Ingestion of fructose relative to glucose resulted in smaller increases in plasma insulin levels and greater brain reactivity to food cues in the visual cortex (in whole-brain analysis) and left orbital frontal cortex (in region-of-interest analysis). Parallel to the neuroimaging findings, fructose versus glucose led to greater hunger and desire for food and a greater willingness to give up long-term monetary rewards to obtain immediate high-calorie foods. These findings suggest that ingestion of fructose relative to glucose results in greater activation of brain regions involved in attention and reward processing and may promote feeding behavior.
Footnotes
- ↵1To whom correspondence should be addressed. Email: kpage{at}usc.edu.
Author contributions: S.L. and K.A.P. designed research; S.L. and K.S. performed research; S.L., J.R.M., and K.A.P. analyzed data; and S.L., J.R.M., and K.A.P. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission. T.F.H. is a Guest Editor invited by the Editorial Board.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1503358112/-/DCSupplemental.
Neurobehavioral effects of fructose vs. glucose
Article Classifications
- Biological Sciences
- Psychological and Cognitive Sciences
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