Processed sugar can not only make you fat, it can wreak havoc on your brain, interfering with memory and learning, according to a study done at the University of California at Los Angeles.
In a press release last week, UCLA said that a new “rat study” is the first research to demonstrate that “a diet steadily high in fructose slows the brain, hampering memory and learning — and how omega-3 fatty acids can counteract the disruption.”
The Journal of Physiology published the findings last Tuesday.
“Our findings illustrate that what you eat affects how you think,” said Fernando Gomez-Pinilla, a professor of neurosurgery at the David Geffen School of Medicine at UCLA and a professor of integrative biology and physiology in the UCLA College of Letters and Science. “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.”
Although prior studies has showed how fructose harms the body through its role in diabetes, obesity and fatty liver, the UCLA research is the first to demonstrate how such sugar influences the brain.
“Sources of fructose in the Western diet include cane sugar (sucrose) and high-fructose corn syrup, an inexpensive liquid sweetener,” UCLA said in its release. “The syrup is widely added to processed foods, including soft drinks, condiments, applesauce and baby food. The average American consumes roughly 47 pounds of cane sugar and 35 pounds of high-fructose corn syrup per year, according to the U.S. Department of Agriculture.”
The researcher said that sugar in fruit doesn’t have him worried.
“We’re less concerned about naturally occurring fructose in fruits, which also contain important antioxidants,” said Gomez-Pinilla, who is also a member of UCLA’s Brain Research Institute and Brain Injury Research Center. “We’re more concerned about the fructose in high-fructose corn syrup, which is added to manufactured food products as a sweetener and preservative.”
Gomez-Pinilla and research 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 flax seed oil and docosahexaenoic acid (DHA), which protects against damage to the synapses — the chemical connections between brain cells that enable memory and learning.
“DHA is essential for synaptic function — brain cells’ ability to transmit signals to one another,” Gomez-Pinilla said. “This is the mechanism that makes learning and memory possible. Our bodies can’t produce enough DHA, so it must be supplemented through our diet.”
The rat were give standard food and trained on a maze twice daily for five days before starting the experimental diet.
“The UCLA team tested how well the rats were able to navigate the maze, which contained numerous holes but only one exit,” the press release said. “The scientists placed visual landmarks in the maze to help the rats learn and remember the way.”
The researchers tested the rats’ ability to recall the route and escape the maze six weeks late.
“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.”
According to UCLA, the DHA-deprived rats also developed signs of resistance to insulin, which controls blood sugar and regulates synaptic function in the brain. A closer look at the rats’ brain tissue suggested that insulin had lost much of its power to influence the brain cells.
“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.
The research believes that fructose caused the DHA-deficient rats’ brain dysfunction. Eating too much fructose could block insulin’s ability to regulate how cells use and store sugar for the energy required for processing thoughts and emotions.
“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.”
Gomez-Pinilla’s advice to humans is keep fructose intake to a minimum, and to eat fresh berries and Greek yogurt instead of the usual desserts, such as hot-fudge sundaes.
sweetener is fine too, he said.
For those who won’t give up their sweets, the researcher advises that they eat food with omega-3 fatty acids, such as salmon, walnuts and flax seeds, or take a daily DHA capsule. Gomez-Pinilla recommends one gram of DHA per day.
“Our findings suggest that consuming DHA regularly protects the brain against fructose’s harmful effects,” said Gomez-Pinilla. “It’s like saving money in the bank. You want to build a reserve for your brain to tap when it requires extra fuel to fight off future diseases.”
The UCLA study was funded by the National Institute of Neurological Disorders and Stroke. Gomez-Pinilla’s lab will next examine the role of diet in recovery from brain trauma.