Recent findings from a study led by researchers at the University of Southern California (USC) shed light on the potential consequences of a high-fat, sugary diet during adolescence, revealing long-lasting memory impairments in rats. The study suggests that dietary habits formed during youth could have enduring effects on cognitive functions.
The study, led by Professor Scott Kanoski and postdoctoral research fellow Anna Hayes from the USC Dornsife College of Letters, Arts and Sciences, focused on understanding the impact of a junk food diet on memory function. The research, published in the journal Behavioral Brain Research, highlights the critical role of acetylcholine, a neurotransmitter crucial for memory and learning, in mediating the effects of diet on brain development.
Key findings from the study include:
Adolescent rats raised on a high-fat, sugary diet exhibited reduced levels of acetylcholine and struggled with memory tests designed to mimic human episodic memory.
Despite switching to a healthier diet in adulthood, the memory impairments persisted, indicating lasting impacts of early dietary choices on brain function.
The potential reversibility of memory issues was explored using acetylcholine-inducing drugs, offering insights into potential avenues for future research on mitigating the impact of poor dietary habits.
The study employed memory tests involving the exploration of new objects in different locations, followed by a recall test to assess memory retention. Rats on the junk food diet showed signs of memory deficits, failing to remember previously encountered objects and their locations, compared to rats in the control group.
Lead author Anna Hayes explained, “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. That signal appears to not be happening in the animals that grew up eating the fatty, sugary diet.”
Professor Kanoski emphasized the sensitivity of adolescence as a critical period for brain development, where dietary influences can have lasting effects. He expressed concern about the potential irreversibility of memory impairments when dietary disruptions occur during childhood.
The researchers also investigated the potential for intervention to reverse memory impairments caused by a junk food diet. Using drugs that induce the release of acetylcholine, such as PNU-282987 and carbachol, directly administered to the hippocampus, a brain region associated with memory, the rats’ memory ability was restored.
However, further research is needed to fully understand how memory problems resulting from a junk food diet during adolescence can be effectively reversed without medical intervention.
The study underscores the importance of promoting healthy dietary habits, particularly during critical periods of brain development in adolescence, to support optimal cognitive function in later life.