High Fat Diets In Mice Could Lead To Learning And Memory Troubles
June 17, 2013

High Fat Diets Could Lead To Learning And Memory Troubles

Michael Harper for redOrbit.com — Your Universe Online

There´s more evidence today that the actions and decisions made in adolescence can have long-term effects that lead into adulthood. The Endocrine Society is gathering this week in San Francisco to share study results and papers with one another and the press. Here, they´ll discuss diabetes, growth hormones, obesity and thyroid cancers. Researchers from CEU-San Pablo University will be taking the stage during this annual meeting to discuss the results of their study that found a high-fat diet could disrupt the brain´s ability to learn and remember things all the way into adulthood. The researchers arrived at this theory after feeding adolescent mice high-fat diets and observing how their spatial memory began to shrink. According to lead author Mariano Ruiz-Gayo, PhD, this kind of memory is vital for recording critical memories, as well as learning new materials and, without it, adults could face challenges in their future.

“This study shows that normocaloric diets containing high amounts of saturated fat might have deleterious and long-lasting effects on the developing brain, even in the absence of apparent diabetes,” said Ruiz-Gayo, a professor of pharmacology at CEU-San Pablo, in a press statement.

The researchers began their study by feeding 15 male adolescent mice a high-fat diet for eight weeks – enough to make them obese, but not enough to develop diabetes. These fat mice received 45 percent of their fat from what´s known as unhealthy fat, or saturated fat. A second group of 15 adolescent male mice acted as the control and received a normal diet with the same amount of calories. The researchers later performed a similar study on adult mice to measure the effects of such a diet later on in life.

After the mice spent eight weeks on their specific diets, the researchers placed them individually in a familiar box that was open on top, had four surrounding walls, and 2 Lego pieces inside. The mice had previously become familiar with the box but were only used to seeing one Lego inside. Ruiz-Gayo and team gave the mice ten minutes to sniff around the box, find the second and new object, and become accustomed to their surroundings. Twenty-five hours later, the researchers introduced the mice back to the same box (complete with both Lego pieces) but moved the second piece to another location. They then measured how long it took the mice to locate the second, new object.

It took the adolescent mice that were fed a diet rich in saturated fats more time to locate the new Lego the second time they were introduced to the box. According to Ruiz-Gayo, this means the spatial memory of these mice had been stunted by the diet while their brains were still immature. This effect was not reversed once they were given a regular calorie diet with regular fats, leading the researchers to believe that any damage done to an immature brain by saturated fats are likely long lasting.

These mice were then taken to the lab to have their brain cells observed. The authors of the paper found the high-fat mice had the structure of their neurons changed, further suggesting a long-term effect on spatial memory that could lead to deficits.

A 2009 study by Oxford University also found high-fat diets in mice could also lead to cognitive disabilities as well as physical weakness.

In this study, adult mice were fed a diet that contained 55 percent saturated fats. After only five days on this diet, the rats were running on a treadmill 30 percent less than regular diet mice and making mistakes sooner when placed in a maze. This study caused the Oxford researchers to worry that even a week´s worth of high fat in a human´s diet could have diverse effects on both the body and mind.