A Junk Food Diet Can Cause Long-Term Damage to Brains

USC researchers found that rats fed a high-fat, high-sugar diet during adolescence showed memory problems.

A recent study by USC researchers, which observed rats eating a high-fat, high-sugar diet, suggests that consuming a lot of junk food during adolescence could have long-term effects on memory function.

“What we see not only in this paper, but in some of our other recent work, is that if these rats grew up on a diet of junk food, then they have memory impairments that don’t go away,” he said. said Scott Kanoski, professor of biological sciences at

” data-gt-translate-attributes=”({“attribute”:”data-cmtooltip”, “format”:”html”})” tabindex=”0″ role=”link”>USC Dornsife College of Letters, Arts and Sciences. “If you just put them on a healthy diet, these effects unfortunately last into adulthood.”

The study appears in the May issue of the journal Brain, behavior and immunity.

In developing the study, Kanoski and lead author and postdoctoral researcher Anna Hayes considered that previous research had shown a link between poor diet and

” data-gt-translate-attributes=”({“attribute”:”data-cmtooltip”, “format”:”html”})” tabindex=”0″ role=”link”>Alzheimer disease. People with Alzheimer’s disease tend to have lower levels of a neurotransmitter called acetylcholine in the brain, which is essential for memory and functions such as learning, attention, wakefulness and involuntary muscle movements.

The team wondered what this might mean for young people who might follow a similar Western diet high in fat and sugar, particularly during adolescence, when their brains are undergoing significant development. By tracking the impact of diet on rats’ acetylcholine levels and subjecting the rats to memory tests, they could learn more about the important relationship between diet and memory.

Experimental results on memory disorders

Researchers tracked the acetylcholine levels of a group of rats fed a high-fat and sugary diet and a control group of rats by analyzing their brain responses to certain tasks designed to test their memory. The team examined the rats’ brains postmortem for signs of disruption in acetylcholine levels.

The memory test involved letting the rats explore new objects in different locations. A few days later, the researchers reintroduced the rats to an almost identical scene, except for the addition of a new object. Rats on the junk food diet showed signs that they could not remember which object they had previously seen and where, while those in the control group showed some familiarity.

“Acetylcholine signaling is a mechanism that helps them encode and remember these events, analogous to ‘episodic memory’ in humans, which allows us to remember events from our past,” explained l lead author Hayes. “This signal does not appear to occur in animals that grew up on a fatty and sugary diet.”

Kanoski emphasized that adolescence is a very sensitive time for the brain, where important changes occur in development. “I don’t know how to say this without sounding like Cassandra and pessimism,” he said, “but unfortunately, some things that may be more easily reversible in adulthood are less so when they occur during childhood.”

There is at least some hope of intervention. Kanoski said that in another series of the study, the research team examined whether memory damage in rats raised on a junk food diet could be reversed with drugs that induce the release of acetylcholine. They used two drugs, PNU-282987 and carbachol, and found that with these treatments delivered directly to the hippocampus, a region of the brain that controls memory and is disrupted in Alzheimer’s disease, the ability The rats’ memory was restored.

But without this special medical intervention, Kanoski said more research is needed to learn how memory problems from a junk food diet during adolescence can be reversed.

Reference: “Consumption of a Western diet impairs memory function via dysregulated acetylcholine signaling in the hippocampus” by Anna MR Hayes, Logan Tierno Lauer, Alicia E. Kao, Shan Sun, Molly E. Klug , Linda Tsan, Jessica J. Rea, Keshav S. Subramanian, Cindy Gu, Natalie Tanios, Arun Ahuja, Kristen N. Donohue, Léa Décarie-Spain, Anthony A. Fodor and Scott E. Kanoski, March 8, 2024, Brain, behavior and immunity.
DOI: 10.1016/j.bbi.2024.03.015

In addition to Kanoski and Hayes, the team included other USC researchers Dornsife, Logan Tierno Lauer, Alicia E. Kao, Molly E. Klug, Linda Tsan, Jessica J. Rea, Keshav S. Subramanian, Cindy Gu , Arun Ahuja, Kristen N. Donohue and Léa Décarie-Spain; Natalie Tanios of the Keck School of Medicine of USC; as well as Anthony A. Fodor, Shan Sun of the University of North Carolina-Charlotte.

The work was supported by the following: National Institute of Diabetes and Digestive and Kidney Diseases grant DK123423 (SEK, AF), National Institute of Diabetes and Digestive and Kidney Diseases grant DK104897 (SEK), Ruth L. Kirschstein National Research Service Postdoctoral Award from the National Institute on Aging F32AG077932 (AMRH), the National Science Foundation Graduate Research Fellowships (separate awards for LT and KSS), the National Institute on Aging Postdoctoral Fellowship 315201 Quebec (LDS) and the Alzheimer’s Association Research Grant to Promote Diversity AARFD-22-972811 (LDS).