Junk Food Can Hurt Your Brain, Too, Study Finds

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By Josh Scherer, Takepart.com

Crossword, sudoku, and Jeopardy! enthusiasts beware: Every french fry and candy bar you consume might be throwing off your game.

A study conducted by researchers at Oregon State University and published in the journal Neuroscience suggests that high-fat, high-sugar diets have a detrimental effect on what they refer to as “cognitive flexibility,” or the power to adapt and adjust to changing situations.

The research was performed using laboratory mice that consumed different diets with varying levels of fat and sugar before facing a gamut of tests—primarily mazes and basic puzzles — to monitor changes in their mental and physical function. The researchers paid specific attention to the types of gut bacteria present in each control group.

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“Bacteria can release compounds that act as neurotransmitters, stimulate sensory nerves or the immune system, and affect a wide range of biological functions,” Kathy Magnusson, a professor in the OSU College of Veterinary Medicine and principal investigator with the Linus Pauling Institute, said in a statement. “We’re not sure just what messages are being sent, but we are tracking down the pathways and the effects.”

In about four weeks, the mental and physical performances of the rats fed on a high-fat, high-sugar diet started to drop significantly, especially when one or more variables in the test changed. One of the most disparate physiological factors within the groups of mice, and the suspected reason for the decreased brain function, was gut bacteria.

People have been paying more attention to their guts than ever. Yogurt companies are using the term “probiotic” to peddle their sugary treats to would-be health junkies, and celebrities like sportscaster Erin Andrews are now digestive health spokespeople for hire, trying to finally make gut bacteria the hip and cool subject it deserved to be all along. But the scientific community has also started paying keener attention to those trillions of stomach-dwelling microflora as well.

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One of the first studies to ever link gut bacteria to brain function was performed by researchers at the Gail and Gerald Oppenheimer Family Center for Neurobiology and Stress, and appeared in the peer-reviewed journal Gastroenterology. They took three groups of women and had one group eat yogurt loaded with supplemental probiotics daily for four weeks, another group eat a substance that looked and tasted like yogurt but had no probiotics, and the third group was given nothing specific to eat. Not only did the sans-probiotic group suffer in cognitive tests, just like the mice did in the recent Oregon State study, but they also faltered in emotion based tests, linking poor gut health to stress.

“This work suggests that fat and sugar are altering your healthy bacterial systems, and that’s one of the reasons those foods aren’t good for you.” Magnusson said. “It’s not just the food that could be influencing your brain, but an interaction between the food and microbial changes.”

Slowly but surely, people are finally starting to go with their gut.