Researchers have uncovered insights into the detrimental effects of early exposure to a Western diet on memory functioning. The study, published in Brain, Behavior, and Immunity, highlights how consumption of processed foods, saturated fats, and simple sugars can lead to lasting deficits in hippocampal-dependent episodic memory, even in the absence of obesity or metabolic dysfunction.
Led by Scott E. Kanoski, a professor of human and evolutionary biology at the University of Southern California, the research underscores the pivotal role of diet in brain health, particularly during developmental stages. It identifies acetylcholine signaling in the hippocampus as a potential mediator of these enduring memory impairments.
Previous studies have established a link between a Western diet and cognitive issues, but the mechanisms underlying these dietary habits’ impact on specific cognitive functions, such as memory, have remained unclear. This study aimed to address this gap to provide actionable insights for public health strategies aimed at preventing cognitive decline.
Kanoski explained, “In addition to promoting obesity and metabolic dysfunction, a diet high in saturated fat, added sugars, and processed foods can lead to memory impairments. We were interested in understanding the underlying neurobiological mechanisms for this connection.”
To investigate the long-term effects of early exposure to a Western diet on cognitive functions, researchers utilized male Sprague Dawley rats, chosen for their well-documented responses in dietary and cognitive research. The study commenced when the rats were on postnatal day 25, a critical developmental period.
The dietary regimen closely resembled the nutritional profile of a Western diet, featuring high-fat, high-sugar, and processed foods. Rats had free-choice access to various such foods and drinks alongside standard chow for control animals.
Results revealed significant and enduring deficits in hippocampal-dependent episodic memory in rats fed a Western diet during early development. Disruptions in hippocampal acetylcholine signaling emerged as a potential mediator. Acetylcholine, crucial for learning and memory processes, exhibited altered dynamics within the hippocampus of Western diet-fed rats.
Moreover, changes in the gut microbiome were observed, but these alterations were mostly reversible with a subsequent healthy diet intervention. However, the cognitive impairments persisted despite the dietary switch, highlighting the enduring impact of early dietary influences on brain function.
Kanoski emphasized the significance of these findings, stating, “What types of food one consumes can have impacts on brain function throughout the lifespan, but particularly during early life periods when brain systems are still developing.” However, he cautioned that these results are based on rodent studies and further research is needed for translational relevance.