Does junk food cause long-term brain damage?

The study appears in the May issue of the journal Brain, Behavior, and Immunity.

Long-term junk food consumption affects key brain regions. The prefrontal cortex, responsible for decision-making and impulse control, shows reduced activity, leading to impaired decision-making and increased impulsivity. The hippocampus, crucial for learning and memory, is also negatively affected, impairing memory retention.

In the study, researchers tracked acetylcholine levels in rats on a fatty, sugary diet and a control group by analyzing brain responses to memory tests. Post-mortem brain examinations were conducted to assess acetylcholine disruptions. The memory test involved rats exploring new objects in different locations, followed by reintroducing them to similar scenes with one new object added. Rats on the junk food diet struggled to remember previously seen objects and their locations, unlike the control group, which showed familiarity.

“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”  said lead author Anna Hayes.

In conclusion, the findings collectively reveal a mechanistic connection between early life exposure to a Western diet (WD), long-lasting contextual episodic memory impairments, and acetylcholine neurotransmission. The α7 nicotinic receptor was found to be a key intermediary of the WD-induced disrupted memory function, and independent of altered metabolic outcomes or general behavior abnormalities persistent memory deficits were observed– and were not specifically linked to alterations in the gut microbiome.