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First known study uncovers what fructose does to your brain

Kathleen Blanchard's picture
Fructose and the brain

Researchers have shown for the first time how fructose affects our brain in ways that could be contributing to diabetes, obesity and more.


Fructose that includes high fructose corn syrup or HFCS behaves differently in the body despite the fact that they have similar chemical compositions.

Investigators from University of Basel performed functional magnetic resonance imaging (fMRI) on twelve healthy young men enrolled in a new study.

Fructose vs Glucose
What the researchers discovered is that fructose - not the kind found in fruits - has a different effect on the brain's reward center, compared to glucose.

What that means is eating becomes less satisfying, making us want to eat more. The problem is that fructose, especially high fructose corn syrup, is added to just about everything, including ketchup.

Glucose causes insulin to be released within minutes, while fructose has very little effect on the hormone that is necessary to keep our blood sugar levels stable.

Fructose and glucose compared in the brain

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Professor Christoph Beglinger from the University Hospital and Professor Stefan Borgwardt from the Psychiatric University Clinics (UPK Basel) who conducted the study looked at how fructose and glucose affect the gastrointestinal tract and the brain.

Men in the study underwent blood work to measure satiety hormones after receiving glucose, fructose or placebo by way of a feeding tube. They also were asked how satisfied they felt. The participants also underwent brain imaging while at rest.

Key findings from the study are as follows:

  • The study participants reported feeling less satisfied after being given fructose, compared to glucose.
  • MRI showed fructose has less effect than glucose on the reward center of the brain, while glucose created a strong signal.
  • Satiety hormones increased only minimally in the blood with fructose, correlating with reports of feelings of satisfaction being lower.

"Fructose consumption from industrially produced foods is increasing worldwide, and this may be accompanied by adverse metabolic consequences." the study authors write.

Compared to glucose, fructose is much sweeter.

The widely used, inexpensive sweetener is suspected to have a negative impact on health and may be contributing to diabetes, obesity, gout and fatty liver disease. Larger studies are needed to validate the findings. Previous studies have shown fructose can have impair memory and hamper learning.

Citation: W├Âlnerhanssen BK, Meyer-Gerspach AC, Schmidt A, Zimak N, Peterli R, Beglinger C, et al. (2015) Dissociable Behavioral, Physiological and Neural Effects of Acute Glucose and Fructose Ingestion: A Pilot Study. PLoS ONE 10(6): e0130280. doi:10.1371/journal.pone.0130280