Junk food found to impair memory

Junk food really can turn your brain to mush, University of New South Wales (UNSW) researchers have discovered. In a study published in the journal Brain, Behavior and Immunity, the researchers showed that rats fed a high-fat, high-sugar diet exhibited impaired memory after just one week.

Interestingly, the results were similarly poor for rats fed a healthy diet that were given access to sugar water to drink.

The rats were found to have inflammation of the hippocampal region of the brain, which is associated with spatial memory. They also suffered cognitive impairment related to place recognition, showing poorer ability to notice when an object had been shifted to a new location.

The rats’ memory changes occurred even before they started to gain weight from the diets.

“We know that obesity causes inflammation in the body, but we didn’t realise until recently that it also causes changes in the brain,” said Professor Margaret Morris, one of the study authors.

“What is so surprising about this research is the speed with which the deterioration of cognition occurred. Our preliminary data also suggests that the damage is not reversed when rats are switched back to a healthy diet, which is very concerning.”

The researchers intend to continue researching how to stop brain inflammation in the animals eating unhealthy diets.

“We suspect that these findings may be relevant to people,” Professor Morris said. “While nutrition affects the brain at every age, it is critical as we get older and may be important in preventing cognitive decline. An elderly person with poor diet may be more likely to have problems.”

The research builds on previous work that has implications for obesity.

“Given that high-energy foods can impair the function of the hippocampus, if you eat a lot of them it may contribute to weight gain by interfering with your episodic memory,” Professor Morris said.

“People might be less aware of their internal cues like hunger pangs and knowing when they have had enough.”

The work was funded by the National Health and Medical Research Council.