Processed Foods May Lead to Memory Loss in Aging Brains

Regularly eating highly processed foods is linked with a lot of health issues. It can make your heart age faster, put you at an increased risk of cardiovascular diseases, and lead to weight gain. A new study finds it may cause problems with your memory, too.

Researchers at Ohio State University investigated the impact of processed food on brain health by modifying the diets of younger and older rats. They found that older rats on a highly processed diet showed several signs of memory issues. However, this seemed to be mitigated by adding an omega-3 fatty acid called DHA to their diets. The study was published in the journal Brain, Behavior, and Immunity.


Ruth Barrientos, senior author and investigator at the OSU Institute for Behavioral Medicine Research, says, “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.”

To conduct the study, the research team randomly assigned 3 and 24-month-old male rats to either their typical diet, a highly processed diet, or a highly processed diet supplemented with DHA. The highly processed diet mimicked human foods like potato chips, frozen pizzas, and preservative-laden deli meats.

After four weeks, the researchers found that the older rats who ate the processed diet but did not get the DHA supplement displayed signs of memory loss that were not found in the younger rats who ate the same diet or the older rats in the DHA group. For example, they forgot having spent time in an unfamiliar space within a few days, which could reflect contextual memory issues associated with the hippocampus. They also lacked a fear response to a danger cue, which is linked to possible problems in the amygdala. Both of these areas of the brain displayed elevated signs of inflammation, as well.


Barrientos says, “The amygdala in humans has been implicated in memories associated with emotional – fear and anxiety-producing – events. If this region of the brain is dysfunctional, cues that predict danger may be missed and could lead to bad decisions.”

Researchers don’t know the exact dose of DHA that the older rats consumed because they all had unlimited access to food. They do note, though, that the findings shouldn’t encourage people to eat a highly processed diet, assuming it will be fine if they just supplement it with DHA. All of the animals on the processed diet still gained substantial weight.

Barrientos explains, “These are the types of diets that are advertised as being low in fat, but they’re highly processed. They have no fiber and have refined carbohydrates that are also known as low-quality carbohydrates. Folks who are used to looking at nutritional information need to pay attention to the fiber and quality of carbohydrates. This study really shows those things are important.”


This research was supported by the National Institute on Aging.

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