The study also discovered that omega-3 fatty acids in fact counteract the disruption. "Our findings illustrate that what you eat affects how you think," Dr. Fernando Gomez-Pinilla, a professor of neurosurgery at the David Geffen School of Medicine at UCLA and integrative biology and physiology at the UCLA College of Letters and Science, said about his study.
"Eating a high-fructose diet over the long term alters you brain's ability to learn and remember information. But adding omega-3 fatty acids to your meals can help minimize the damage," Gomez-Pinilla said.
Although earlier research has revealed how fructose harms the body through its role in diabetes, obesity and fatty liver, this study is the first to uncover how the sweetener influences the brain.
In their study, they researched 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 flax seeds oil and docosahexaenioc acid (DHA)--which protects against damage of the chemical connections between brain cells that enable memory and learning.
The researchers fed the rats normal rat chow for five days and trained the rats in a maze twice a day before starting the experimental diet. They tested how well the rats were able to navigate the maze, which contained numerous holes but only one exit. Six weeks later, they tested the rats' ability to recall the route and escape the maze, and realized that there was a great difference in performance.
"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. The brain cells had trouble signaling eachother, disrupting the rats' ability to think clearly and recall the route they'd learned six weeks earlier."
The DHA-deprived rats also developed signs of resistance to insulin, a hormone that controls blood sugar and regulates synaptic function in the brain. Taking a closer look a the rats' brain tissue suggested that insulin had lost much of its power to influence the brain cells.
"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," he said. "Our study shows that a high-fructose diet harms the brain as well as the body. This is something new."