While parents commonly recognize the harmful effects of drugs and alcohol on a child’s developing brain, recent research suggests that mothers and fathers should also consider candy bars as detrimental as beer cans. A study conducted at the University of Southern California, using rodents, revealed that rats fed a diet rich in fat and sugar during adolescence experienced long-term memory impairment that persisted well into adulthood.
Overall, the study authors believe these findings indicate that a diet filled with junk food may disrupt a teenager’s memory function for an extended period, akin to the effects observed in rats.
Scott Kanoski, a professor of biological sciences at the USC Dornsife College of Letters, Arts and Sciences, stated in a media release, “What we see not just in this paper, but in some of our other recent work, is that if these rats grew up on this junk food diet, then they have these memory impairments that don’t go away. If you just simply put them on a healthy diet, these effects unfortunately last well into adulthood.”
During the study’s development, Prof. Kanoski and postdoctoral research fellow Anna Hayes considered prior research linking poor diet to Alzheimer’s disease. Individuals with Alzheimer’s disease often exhibit reduced levels of the neurotransmitter acetylcholine in their brains. Acetylcholine plays a crucial role in memory, as well as various other functions such as learning, attention, arousal, and involuntary muscle movement.
This led researchers to speculate about the implications for younger individuals following a similar fat-laden, sugary Western diet, particularly during adolescence when their brains undergo significant development. By monitoring the diet’s impact on the rodents’ acetylcholine levels and subjecting the rats to memory tests, researchers gained valuable insights into the intricate relationship between diet and memory.
Subsequently, the study authors monitored acetylcholine levels in a cohort of rats subjected to a diet high in fat and sugar, alongside a control group of rats. They assessed their brain responses to specific tasks designed to evaluate memory. Following this, researchers examined the rats’ brains post-mortem for any indications of disrupted acetylcholine levels.
The memory assessment utilized in the study involved permitting the rats to explore novel objects positioned in various locations. Subsequently, days later, researchers reintroduced the rats to a setting that was nearly identical, except for the inclusion of one new object. Rats exposed to the junk food diet exhibited signs of struggling to recall which objects they had previously encountered and their respective locations. Conversely, those in the control group demonstrated greater familiarity with their surroundings.
“Acetylcholine signaling is a mechanism to help them encode and remember those events, analogous to ‘episodic memory’ in humans that allows us to remember events from our past,” Hayes explains. “That signal appears to not be happening in the animals that grew up eating the fatty, sugary diet.”
