Can Sugar Make You Dumb?

Your Brain on Sugar
Your Brain on Sugar

By Sally Jones

A new study suggests that it just may. But a diet rich in omega-3s may help counter the effects.

Researchers at the University of California Los Angeles (UCLA) tested rats on the Barnes maze both before and after feeding them a diet of fructose in their water. After six weeks, the rats showed significant memory loss and impaired abilities in the maze. Researchers found these rats exhibited signs of insulin-resistance. Insulin, a hormone that controls blood sugar, also helps regulate brain function.

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"Because insulin can penetrate the blood-brain barrier, the hormone may signal neurons to trigger reactions that disrupt learning and cause memory loss," according to Fernando Gomez-Pinilla, a professor of neurosurgery at the David Geffen School of Medicine at UCLA. "Insulin is important in the body for controlling blood sugar, but it may play a different role in the brain, where insulin appears to disturb memory and learning."

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"Our study shows that a high-fructose diet harms the brain as well as the body. This is something new," he says. Fructose can include cane sugar as well as high-fructose corn syrup-common ingredients in many foods that are staples of the U.S. diet, including soda, bread, ketchup, crackers and cookies.

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But the news was not all bad: A subset of rats fed omega-3s in their fructose mix were not as adversely affected.

"Our findings illustrate that what you eat affects how you think," said Fernando Gomez-Pinilla. "Eating a high-fructose diet over the long term alters your brain's ability to learn and remember information. But adding omega-3 fatty acids to your meals can help minimize the damage."

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This study just appeared in the Journal of Physiology.

Journal of Physiology