Will a High-Fructose Diet Make You Stupid?


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Cola. Photo: Shutterstock

Can a diet of Twinkies and cola negatively affect your memory? That's what scientists who conducted a study on rats in the Journal of Physiology are suggesting. 

“Our study shows that a high-fructose diet harms the brain as well as the body,” University of California, Los Angeles, neurosurgeon and study author Fernando Gomez-Pinilla said in a press release. “This is something new.”

Gomez-Pinella and crew spent five days training 24 rats to navigate a maze and fed them a diet of rat food. All of the rats took a similar amount of time to get through the maze, and they cut down those times at a similar rate over the course of a week. After the first week, the scientists divided the rats into four groups of six. One group had Omega-3 fatty acids added to their normal food. A second group got Omega-3 fatty acids and water with fructose, one of the main ingredients in high-fructose corn syrup. A third group had just water with fructose added to their chow. The fourth group was kept on the plain rat food diet. After six weeks, the animals were put back in the maze.

The Omega-3 fatty acid group exited the maze the quickest, the control group finished with the second fastest times, the Omega-3 and fructose group finished with the third fastest times, and the fructose group took the most time to navigate the maze.

The total caloric intake and body weight was similar for all groups, suggesting that obesity was not a contributing factor to the slower times. In other words, the rats that ingested the high-fructose corn syrup weren’t slower because they were fatter.

Omega-3s are known to protect damage to the synapses—connections between brain cells that allow for memory and learning. The rats that had Omega-3s in their diets had more synaptic firing. Those on a diet of fructose, had less synaptic firing. Those on a diet of fructose also had signs of insulin resistance—an inability of cells to absorb and store sugar which can lead to increases in insulin and triglycerides in the blood stream. The scientists suspect that an increase in insulin and/or triglycerides in the blood may have somehow led brain cells and synapses to go a bit haywire, requiring more time for the rats to process their memories. “Because insulin can penetrate the blood–brain barrier, the hormone may signal neurons to trigger reactions that disrupt learning and cause memory loss,” Gomez-Pinilla said.

In case you're wondering, salmon, walnuts, and flaxseed are rich in Omega-3s.

—Joe Spring

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