Is western diet linked to lasting memory issues? - Video
Overview
In a recent study published in the journal Brain, Behavior, and Immunity, researchers developed an initial-life Western diet (WD) murine model associated with long-term hippocampal (HPC) dysfunction to examine the neurobiological processes underlying these effects.
The Western diet, rich in processed foods, saturated fats, and simple carbs, harms memory, especially hippocampus-dependent functions. Its impact on brain development and long-term hippocampal damage is unclear. However, it alters synaptic plasticity, lowers BDNF levels, and increases neuro-inflammation markers. Additionally, disruptions in acetylcholine signaling may worsen Western diet-related memory issues.
In this study, researchers looked at how a diet similar to the Western diet during early life affects memory in rats. They used a cafeteria-style diet, like junk food, to mimic the Western diet in humans. Some rats ate this diet during their youth, while others ate regular rat food. They then measured their weight and food intake regularly. The rats on the cafeteria diet had memory problems even after switching to healthier food later in life. The researchers also studied the levels of certain proteins related to memory in the rats' brains. They used memory tests to see how well the rats remembered things.
The study found that rats who ate a Western-style diet early in life had lasting memory problems, even after switching to healthier food later on. Specifically, they had trouble remembering spatial information. However, their ability to recognize new items wasn't affected as much if it didn't involve using a specific part of the brain called the hippocampus.
Key findings of the study:
- There was hippocampus-dependent contextual episodic memory impairments in CAF rats that persisted despite the healthy diet intervention.
- Given that dysregulated HPC acetylcholine (ACh) signaling is associated with memory impairments in humans and animal models, the researchers examined protein markers of ACh tone in the dorsal HPC (HPCd) in CAF and CTL rats.
- Results revealed significantly lower protein levels of vesicular ACh transporter in the HPCd of CAF vs. CTL rats, indicating chronically reduced ACh tone.
- Using intensity-based ACh sensing fluorescent reporter (iAChSnFr) in vivo fiber photometry targeting the HPCd, the researchers next revealed that ACh release during object-contextual novelty recognition was highly predictive of memory performance and was disrupted in CAF vs. CTL rats.
- Neuropharmacological results showed that alpha 7 nicotinic ACh receptor agonist infusion in the HPCd during training rescued memory deficits in CAF rats.
The findings highlighted that early exposure to a Western diet (WD) was associated with long-term episodic memory deficits mediated by altered hippocampal acetylcholine (ACh) transmission.
Reference: Anna M.R. Hayes et al., Western diet consumption impairs memory function via dysregulated hippocampus acetylcholine signaling, Brain, Behavior, and Immunity, 2024.
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