How highly processed foods harm memory in the aging brain
Study in animals suggests omega-3 may reduce effects

Date:
October 14, 2021
Source:
Ohio State University
Summary:
Four weeks on a diet of highly processed food led to a strong
inflammatory response in the brains of aging rats that was
accompanied by behavioral signs of memory loss, a new study has
found. 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.



FULL STORY ==========================================================================
Four weeks on a diet of highly processed food led to a strong inflammatory response in the brains of aging rats that was accompanied by behavioral
signs of memory loss, a new study has found.


========================================================================== 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.

Barrientos' lab studies how everyday life events -- such as surgery,
an infection or, in this case, an unhealthy diet -- might trigger
inflammation in the aging brain, with a specific focus on the hippocampus
and amygdala regions.

This work builds on her previous research suggesting a short-term,
high-fat diet can lead to memory loss and brain inflammation in older
animals, and that DHA levels are lower in the hippocampus and amygdala
of the aged rat brain.

DHA, or docosahexaenoic acid, is an omega-3 fatty acid that is present
along with eicosapentaenoic acid (EPA) in fish and other seafood. Among
DHA's multiple functions in the brain is a role in fending off an
inflammatory response -- this is the first study of its ability to act
against brain inflammation brought on by a processed diet.

The research team randomly assigned 3-month-old and 24-month-old
male rats to their normal chow (32% calories from protein, 54% from
wheat-based complex carbs and 14% from fat), a highly processed diet
(19.6% of calories from protein, 63.3% from refined carbs -- cornstarch, maltodextrin and sucrose - - and 17.1% from fat), or the same processed
diet supplemented with DHA.



========================================================================== Activation of genes linked to a powerful pro-inflammatory protein
and other markers of inflammation was significantly elevated in the
hippocampus and amygdala of the older rats that ate the processed diet
alone compared to young rats on any diet and aged rats that ate the DHA-supplemented processed food.

The older rats on the processed diet also showed signs of memory loss
in behavioral experiments that weren't evident in the young rats. They
forgot having spent time in an unfamiliar space within a few days,
a sign of problems with contextual memory in the hippocampus, and did
not display anticipatory fear behavior to a danger cue, which suggested
there were abnormalities 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.

The results also showed that DHA supplementation of the processed-food
diets consumed by the older rats effectively prevented the elevated inflammatory response in the brain as well as behavioral signs of
memory loss.

Researchers don't know the exact dosage of DHA -- or precise calories
and nutrients -- taken in by the animals, which all had unlimited access
to food.

Both age groups gained a significant amount of weight on the processed
diet, with old animals gaining significantly more than the young
animals. DHA supplementation had no preventive effect on weight gain
associated with eating highly processed foods.

That was a key finding: Barrientos cautioned against interpreting
the results as a license for consumers to feast on processed foods as
long as they take a DHA supplement. A better bet to prevent multiple
negative effects of highly refined foods would be focusing on overall
diet improvement, she said.

"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," she
said. "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, the National Institute of Dental
and Craniofacial Research, and the Ohio Agricultural Research and
Development Center. Co-authors include Michael Butler, Nicholas Deems, Stephanie Muscat and Martha Belury from Ohio State and Christopher Butt
of Inotiv Inc. in Boulder, Colorado.

========================================================================== Story Source: Materials provided by Ohio_State_University. Original
written by Emily Caldwell. Note: Content may be edited for style and
length.


========================================================================== Journal Reference:
1. Michael J. Butler, Nicholas P. Deems, Stephanie Muscat,
Christopher M.

Butt, Martha A. Belury, Ruth M. Barrientos. Dietary DHA prevents
cognitive impairment and inflammatory gene expression in aged
male rats fed a diet enriched with refined carbohydrates. Brain,
Behavior, and Immunity, 2021; 98: 198 DOI: 10.1016/j.bbi.2021.08.214 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211014172753.htm

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