Professor Fernando Gomez-Pinilla, main author of the study on fructose and omega-3 fatty acids. (Photo: UCLA)
Sugar hampers brain function, fish oil counters the effects: study
Monday, May 21, 2012, 01:50 (GMT + 9)
A new rat study at the University of California, Los Angeles (UCLA) is the first to show that a diet steadily high in fructose thwarts memory and learning — and that omega-3 fatty acids can counteract it.
The findings were published in the Journal of Physiology this week.
"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 minimise the damage."
Sources of fructose include cane sugar (sucrose) and high-fructose corn syrup, which is extensively added to processed foods including soft drinks, condiments and baby food.
Gomez-Pinilla, who is also a member of UCLA's Brain Research Institute and Brain Injury Research Centre, and study co-author Rahul Agrawal, a UCLA visiting postdoctoral fellow from India, studied two groups of rats that were each fed a fructose solution as drinking water for six weeks. The second group also received omega-3 fatty acids via flaxseed oil and docosahexaenoic acid (DHA), which prevents 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 animals were fed standard rat food and trained on a maze twice daily for five days before starting the experiment. The team tested how well the rats were able to navigate the maze and placed visual landmarks to help the rats learn and remember.
"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."
He thinks fructose is the reason behind the DHA-deficient rats' brain dysfunction.
He recommends that people keep their sugar intake low -- and eat foods rich in omega-3 fatty acids, like salmon, or take a daily DHA capsule of 1 g.
"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."
By Natalia Real