Australian researchers found that even a short term diet of junk food can have a detrimental effect on the brain’s cognitive ability
Scientists from the University of New South Wales showed for the first time that rats fed a diet high in fat and sugar had impaired memory after a week
The study suggests obesity causes rapid changes in the brain and the damage of an unhealthy diet is not reversed
Everyone knows that junk food is bad for the waistline, but new research suggests it can damage memory, too.
Australian researchers found that even a short term diet of junk food can have a detrimental effect on the brain’s cognitive ability.
The study suggests that obesity can trigger rapid changes in the brain. Scientists from the University of New South Wales (UNSW) showed for the first time that rats fed a diet high in fat and sugar had impaired memory after just a week.
Interestingly, the results were similarly poor for the rats fed a healthy diet that had been given sugar water to drink, according to the study, which was published in the journal Brain, Behaviour and Immunity.
The animals found it more difficult to recognise specific places after their junk food diet and showed a lesser ability to notice when an object shifted to a new location. The mice also had inflammation of the hippocampal region of the brain, which is associated with spatial memory.
‘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 from UNSW Medicine, who co-authored the study.
‘What is so surprising about this research is the speed with which the deterioration of the cognition occurred,’ she said.
‘Our preliminary data also suggests that the damage is not reversed when the rats are switched back to a healthy diet, which is very concerning.’
Some aspects of the animals' memories were spared, regardless of their diets.
All the animals were equally able to recognise objects after eating either the healthy, healthy with sugar or ‘cafeteria’ diets, the latter of which was high in fat and sugar, including cake, chips and biscuits.
The change in the animals' memory appeared even before the mice eating junk food gained any weight.
Ongoing work will attempt to establish how to stop the inflammation in the brain of animals with the unhealthy diets, which could unlock secrets relating to humans who eat unhealthily.
‘We suspect that these findings may be relevant to people,’ said Professor Morris.
‘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,’ she said.