High-fat diet’s negative effect on memory may fade

CHICAGO — Eating a high-fat diet as a youngster can affect learning and memory during adulthood, studies have shown. But new findings suggest such diets may not have long-lasting effects. Rats fed a high-fat diet for a year recovered their ability to navigate their surroundings.

University of Texas at Dallas neuroscientist Erica Underwood tested spatial memory for rats fed a high-fat diet for either 12 weeks or at least 52 weeks, immediately after weaning.  After rats placed in a chamber-filled box containing Lego-like toys became familiar with the box, the researchers moved the toys to new chambers. Later, when placed in the box, rats who ate high-fat foods for 12 weeks appeared confused and had difficulty finding the toys. But rats that ate high-fat foods for a year performed as well as those fed a normal diet. Underwood repeated the experiment, posing additional spatial memory tests to new groups of rats. The findings were the same: Over the long-term, rats on high-fat diets recovered their ability to learn and remember.

Studies of brain cells revealed that rats on the long-term high-fat diet showed reduced excitability in nerve cells from the hippocampus, the same detrimental effects seen in rats on the short-term high-fat diet.

“The physiology that should create a dumber animal is there, but not the behavior,” said Lucien Thompson of UT Dallas, who oversaw the study.

Underwood and Thompson speculate that some other part of the brain may be compensating for this reduction in neural response.