Two groups of rats were given a solution containing high-fructose corn syrup as water by researchers at the University of California Los Angeles for six weeks.
One of the groups was also given omega-3 fatty acids with brain-boosting qualities, while the other was not.
Before the drinks were administered, the rats were trained for five days in a complicated maze, said AFP. After six weeks, the group of rats which were not given fatty acids were slower.
Fernando Gomez-Pinilla, a professor of neurosurgery at the David Geffen School of Medicine at UCLA, said, "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."
Gomez-Pinilla said, "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," according to LiveScience.
High-fructose corn syrup is six times sweeter than cane sugar and commonly added to soda, processed foods, condiments and baby good, said LiveScience.
The US Department of Agriculture said the average American consumes more than 40 pounds of high-fructose corn syrup per year.
The researchers found that the rats fed only high-fructose corn syrup developed insulin resistance, which they think may be interfering with the cells' ability to use and store sugar.
Science Daily noted that high-fructose corn syrup has also been connected to diabetes, obesity and fatty liver.
Gomez-Pinilla said, "Our study shows that a high-fructose diet harms the brain as well as the body. This is something new."