You gotta love scientists. They never seem to believe anything unless or until they scientifically prove it. Even if it’s obvious. Fernando Gomez-Pinilla, a professor of neurosurgery and integrative biology at UCLA recently had this to say after completing a study on how a high-fructose diet affects your brain: “Our findings illustrate that what you eat affects how you think.”
Duh! Even I could have told you that. Yet I can’t help feeling a little justified by the rest of the findings of their study. I feel confirmed as a mother and as a lover of traditional, Real Food. While past studies on high levels of fructose consumption concentrated on the effect fructose had on the development of diabetes, fatty liver disease, and weight gain, this is the first study published to concentrate on the effect fructose has on the brain.
Turns out, it makes you stupid.
Gomez-Pinilla and study 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 flaxseed 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 animals were fed standard rat chow 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 scientists placed visual landmarks in the maze to help the rats learn and remember the way.
Six weeks later, the researchers tested the rats’ ability to recall the route and escape the maze. What they saw surprised them.
“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.”
The DHA-deprived rats also developed signs of resistance to insulin, a hormone that 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.
He suspects that fructose is the culprit behind 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.”
Does this mean you should stop eating fruit or other foods naturally high in fructose?
No way! When fructose occurs in nature, it’s usually part of a whole food full of anti-oxidants, fiber, pectin, and other goodies that can slow the digestion of fructose and mitigate it’s damage. Given the packaging, you’re not likely to eat all that much fructose anyway. Who sits down and eats a dozen apples?
But what about that fructose in table sugar? The fructose in corn syrup?
These, you should certainly avoid. They’re refined and concentrated unnaturally, and they’re easily consumed in excess.
I also appreciate that the study confirms the protective nature of wild caught seafood, eggs from pastured hens, and organ meats — nature’s most concentrated sources of DHA.
So, rather than reaching for the caramel macchiato or other sugary snack when it’s time to cram for finals or learn something new, we should be reaching for real brain food like fish roe or fermented cod liver oil! (Where to find fermented cod liver oil.)
What’s your favorite brain food? And how often do you eat it?
(photo by jennifertomaloff)