A new study by Ohio State University revealed how highly processed foods negatively impact brain health. Researchers fed older rats a diet high in refined carbohydrates for four weeks and noticed significant changes. Food given to the rats mimicked ready-made, prepackaged human foods such as chips, frozen dinners, and deli meats.
Their brains showed inflammation, memory loss, and general cognitive decline. However, OSU researchers didn’t notice inflammation or cognitive deficits in the brains of young rats eating a processed diet. A control group of both young and aging rats given a healthy diet also showed no signs of memory loss.
The team also found a way to improve the rats’ cognitive function. They gave them a DHA (an omega-3 fatty acid) supplement, which prevented memory problems and reduced inflammation almost wholly in the rats.
Eating foods high in sugar and laden with chemicals links obesity to type 2 diabetes. Because of this, researchers suggest that older populations, in particular, should limit processed foods and opt for DHA-rich foods, like salmon, instead. It’s imperative since study findings showed brain damage occurred in such a short time.
The researcher made a bold statement about highly processed foods
Ruth Barrientos, an investigator and senior study author for The Ohio State University Institute for Behavioral Medicine Research, said this in a press release:
“The fact we’re seeing these effects so quickly is a little bit alarming. “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 journal Brain, Behavior, and Immunity published the findings.
OSU researchers explain how highly processed foods harm the brain
Barrientos’ research focuses on how highly processed foods affect the hippocampus and amygdala in particular. This study builds on prior research showing that temporary high saturated fat diets can cause memory impairment and brain inflammation in older animals. Another study found that aging rats have lower DHA levels in the hippocampus and amygdala brain regions.
Fish and other seafood have high amounts of DHA, along with the fatty acid eicosapentaenoic acid (EPA). For vegans and vegetarians, algal oil derived from algae provides a great source of DHA. One study found that algal oil is comparable to cooked salmon in terms of nutrient availability and absorption of DHA.
DHA boosts brain health in many ways, including warding off inflammation. This study marks the first to show how DHA can protect against brain inflammation despite eating highly processed foods.
For the study, the team separated the rats into three groups. The first group of 3-month-old and 24-month-old male rats ate their regular diet (32% calories from protein, 54% from wheat-based complex carbs, and 14% from fat. Researchers gave the second group highly processed foods (19.6% of calories from protein, 63.3% from refined carbs – cornstarch, maltodextrin, and sucrose – and 17.1% from fat). The final group ate a processed diet with a DHA supplement.
Unsurprisingly, the results showed that older rats on a processed diet had significantly higher inflammatory markers in the hippocampus and amygdala. Young rats on any diet and aging rats eating the DHA-supplemented processed diet had lower inflammation.
Furthermore, the older rats eating foods with more processing had more significant memory loss in behavioral tests. After a few days, they couldn’t remember being in an unfamiliar place and had contextual memory loss in the hippocampus. Finally, they showed no sign of fear when presented with danger, indicating disruptions in the amygdala.
“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,” Barrientos said.
Rats in DHA-supplemented diet fared better.
When older rats ate a processed diet supplemented with DHA, they had lower inflammation and fewer signs of memory loss. However, researchers didn’t measure the exact dosage of DHA or calories consumed by the rats.