Diet and Brain Health

Western Diet May Cause Memory Damage to Developing Brains

Wondering what junk food does to developing brains?  Whether it’s a burger and fries or funnel cake at the state fair, Americans in particular fuel the demand for high-fat and high-sugar foods. Despite the word “diet,” the nickname “Western Diet” isn’t about restricting calories to lose weight or improve one’s health. In fact, the term simply refers to the unhealthy eating habits many Americans have adopted to regularly consume foods such as:

• Prepackaged foods

• Red meats, eggs, potatoes and corn

• High-sugar drinks

• Refined grains

• Fried foods

• High-fat dairy products

• Processed meats

• Candy and sweets

Among the many health concerns, the Western Diet has been linked to decreased gut microbiome health, increased inflammation, obesity, and countless chronic diseases. Now a new study seems to point to another significant concern: memory damage to developing brains.

The Research

A team of USC Dornsrife researchers wanted to investigate the effects of a Western Diet on acetylcholine (ACh), a neurotransmitter that plays a significant role in learning, attention, memory, and arousal. Knowing that low levels of ACh are linked to Alzheimer’s, they were curious if the damaging effects of a high-sugar, high-fat diet during development could be reversed by switching to a healthy diet in adulthood.

For the study, a group of juvenile and adolescent rats were divided into two groups. The control group was given standard chow while the test group was provided access to as much “junk food” and water as they wanted. Made to mimic the Western Diet, the experimental group’s food included high-fat, high-sugar chow, potato chips, peanut butter cups, and high-fructose corn syrup.

When the rats in (in both groups) reached adulthood, the researchers administered memory tests. These tests included putting the rats in new locations in which they would encounter new objects, then reintroducing them to the novel location after some days with one new object being added to the location.

The Results

Although the control group exhibited curiosity regarding the new object placed in the location, the experimental group (on the Western Diet) seemed not to notice the new object.

Unfortunately, even after the experimental group was switched to a healthy diet, their memory deficiencies persisted. This suggested that the rats likely had long-lasting damage to their brains.

When looking at these test rats’ brains, the researchers found compromised ACh signaling in the hippocampus. In both rats and humans, the hippocampus is associated with memory and learning.

“The hippocampus is a brain region that is particularly susceptible to various environmental and biological insults,” explains USC Dornsrife Professor of Biological Sciences Scott Kanoski, PhD, MS, who served as senior investigator for the study. “This is particularly true during the juvenile and adolescent periods when this brain region is still developing. Our diet model produced acetylcholine disruption in the hippocampus in the rats analogous to disruptions observed in Alzheimer’s diseases. However, more work is needed to understand how early life dietary and metabolic factors influence long-term risk for Alzheimer’s and other related dementias.”

Limitations of the Study

To be clear, the study didn’t provide evidence of permanent memory issues and it DID indicate that any gut microbiome changes caused by the Western Diet could be reversed with a healthy diet. As we learn more about the gut-brain connection, it’s logical to theorize that improving the gut microbiome might also improve memory. In addition, it’s not known whether keeping the rats on a healthy diet for a longer period of time would have returned the neurotransmitters to normal.

It’s also worth noting that in another phrase of their research the scientists were able to restore the rats’ memory by administering two drugs (PNU-282987 and carbachol) directly into the rats’ hippocampi.

The research was published in the May 2024 edition of the journal, “Brain, Behavior and Immunity.”


Wendy Burt-Thomas writes about the brain, mental health and parenting.

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