Saturday, September 5, 2009
High-fat diets can make us stupid
Sent by: Professor Mukund Apte, Pune
(4 Sep 2009 – IANSS)
Rats fed a high-fat diet exhibit stark reduction in their physical endurance and cognitive ability after just nine days, says a new study.
The research, funded by the British Heart Foundation, may have implications not only for high-fat addicts, but also athletes looking for the optimal diet for training and patients with metabolic disorders. “We found that rats, when switched to a high-fat diet from their standard low-fat feed, showed a surprisingly quick reduction in their physical performance,” says Andrew Murray, who led the study at Oxford University and is now with the University of Cambridge. “After just nine days, they were only able to run 50 percent as far on a treadmill as those that remained on the low-fat feed,” adds Murray. High-fat diets, prevalent in western countries, are known to be harmful in the long term and can lead to obesity, diabetes and heart failure.
The Oxford team set out to investigate whether rats fed a high-fat diet for just a few days showed any change in their physical and cognitive abilities.
All 42 rats were initially fed a standard feed with a low fat content of 7.5 percent. Their physical endurance was measured by how long they could run on a treadmill and their short-term or ‘working’ memory was measured in a maze task. Half of the rats were then switched to a high-fat diet where 55 percent of the calories came from fat. After four days of getting used to the new diet, the endurance and cognitive performance of the rats on the low- and high-fat diets were compared for another five days. “With the standard feed, 7.5 percent of the calories come from fat. That’s a pretty low-fat diet, much like humans eating nothing but muesli,” says Murray.
“The high-fat diet, in which 55 percent of the calories came from fat, sounds high but it’s actually not extraordinarily high by human standards. A junk food diet would come close to that,” Murrray adds. On the fifth day of the high-fat diet (the first day back on the treadmill), the rats were already running 30 percent less far than those remaining on the low-fat diet. By the ninth day, the last of the experiment, they were running 50 percent less far, says a Cambridge release. The rats on the high-fat diet were also making mistakes sooner in the maze task, suggesting that their cognitive abilities were also being affected by their diet.
These findings were published in the FASEB journal.