Researchers also found that supplementing the processed diet with the omega-3 fatty acid DHA prevented memory problems and reduced the inflammatory effects almost entirely in older rats.
Neuroinflammation and cognitive problems were not detected in young adult rats that ate the processed diet.
The study diet mimicked ready-to-eat human foods that are often packaged for long shelf lives, such as potato chips and other snacks, frozen entrees like pasta dishes and pizzas, and deli meats containing preservatives.
Highly processed diets are also associated with obesity and type 2 diabetes, suggesting older consumers might want to scale back on convenience foods and add foods rich in DHA, such as salmon, to their diets, researchers say – especially considering harm to the aged brain in this study was evident in only four weeks.
“The fact we’re seeing these effects so quickly is a little bit alarming,” said senior study author Ruth Barrientos, an investigator in The Ohio State University Institute for Behavioral Medicine Research and associate professor of psychiatry and behavioral health.
“These findings indicate that consumption of a processed diet can produce significant and abrupt memory deficits – and in the aging population, rapid memory decline has a greater likelihood of progressing into neurodegenerative diseases such as Alzheimer’s disease. By being aware of this, maybe we can limit processed foods in our diets and increase consumption of foods that are rich in the omega-3 fatty acid DHA to either prevent or slow that progression.”
The research is published in the journal Brain, Behavior, and Immunity.