Fernando Gomez-Pinilla of the David Geffen School of Medicine at UCLA, said high-fructose corn syrup -- an inexpensive liquid six times sweeter than cane sugar -- is commonly added to processed foods, including soft drinks, condiments and baby food.
Gomez-Pinilla and study co-author Rahul Agrawal, a UCLA visiting postdoctoral fellow from India, studied two groups of rats that each consumed a fructose solution as drinking water for six weeks. The second group also received omega-3 fatty acids in the form of flaxseed oil and docosahexaenoic acid (DHA), which protects against damage to the synapses -- the chemical connections between brain cells that enable memory and learning.
The animals were fed standard rat chow and trained on a maze twice daily for five days before starting the experimental diet. The scientists placed visual landmarks in the maze to help the rats learn and remember the way.
Six weeks later, the researchers tested the rats' ability to recall the route and escape the maze.
"The second group of rats navigated the maze much faster than the rats that did not receive omega-3 fatty acids," Gomez-Pinilla said. "The DHA-deprived animals were slower, and their brains showed a decline in synaptic activity. Their brain cells had trouble signaling each other, disrupting the rats' ability to think clearly and recall the route they'd learned six weeks earlier."
The findings were published in the Journal of Physiology.