Cobbler Not So Peachy

Sugar may decrease brain power while fish and nuts will help it

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Before you reach for a second helping of peach cobbler with vanilla bean ice cream this weekend, you might want to consider how all that sugar will hit your brain cells.

A recent study using animals has shown that a diet with too much sugar might help clog up the brain, slowing down learning and weakening your memory.

The good news is a bit of extra tuna casserole or a couple extra deviled eggs - even some walnuts on your ice cream - might help offset the damage by upping your omega-3 fatty acid intake.

"Cut down your sugar intake."

Fernando Gomez-Pinilla, a neurosurgery professor at UCLA's David Geffen School of Medicine, led a study that experimented with the effects of extra sugar in rats' diet, as well as the effects of omega-3 fatty acids on them.

Conducting an experiment of this sort may not be regarded as ethical on humans, so the rat study is one of the only ways the researchers might learn about effects that may exist in humans as well.

Gomez-Pinilla and co-author Rahul Agrawal, a UCLA postdoctoral fellow from India, trained two groups of rats on a maze two times a day for five days, testing their ability to get to the maze's only exit. The rats ate regularly rat food during this time.

Then the researchers began a six-week experiment in which they fed the rats a solution of high-fructose corn syrup as drinking water. High-fructose corn syrup is an inexpensive sweetener used in a wide range of common products, from soft drinks to baby food to processed foods.

During the study, one of the rat groups was also fed flaxseed oil for its omega-3 fatty acids and a chemical called docosahexaenoic acid (DHA), which can protect the brain's memory and learning highways from damage.

After six weeks, Gomez-Pinilla and Agrawal tested the rats in the maze again.

"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."

Gomez-Pinilla said the sugar-drunk rats couldn't seem to follow the landmarks to the end of the maze.

"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 said.

Less surprisingly, the rats who did not receive DHA began to show signs of insulin resistance, an early symptom of developing diabetes. Insulin controls blood sugar levels and some of the communication functions between neurons in the brain, and the researchers believe the insulin had lost some of its influence over brain cell functioning.

The abnormal functioning of the insulin might "trigger reactions that disrupt learning and cause memory loss," according to Gomez-Pinilla.

It's unclear whether the impact of the sugar on the rats would have a similar effect on humans over the long term, especially because the rats' diet included a proportionally higher intake of fructose than would be likely for humans.

Past research has shown the positive effects of omega-3 fatty acids on the brain in humans, and this study may begin to show the possible effects of sugar on brains that would require further study.

The study appeared online May 15 in The Journal of Physiology. The research was funded by the National Institutes of Health. No conflicts of interest were reported.

Reviewed by: 
Review Date: 
May 25, 2012
Last Updated:
August 15, 2012