Inter-relationships among diet, obesity and hippocampal-dependent cognitive function

Area of Science:

• Neuroscience
• Dietary Science
• Cognitive Psychology

Background:

• Western diets (WD) high in fat and sugar are linked to hippocampal dysfunction and cognitive deficits.
• Diet-induced obesity (DIO) is a growing concern with potential neurological consequences.

Purpose of the Study:

• To investigate the effects of WD and ketogenic (KETO) diets on hippocampal-dependent learning and memory.
• To examine the relationship between diet, obesity, blood-brain barrier (BBB) integrity, and cognitive performance.

Main Methods:

• Rats were trained on hippocampal-dependent and independent tasks.
• Following training, rats were maintained on WD, KETO diet, or chow (CHOW) for up to 90 days.
• Cognitive performance, BBB permeability, blood glucose, and body weight were assessed.

Main Results:

• WD-fed rats showed impaired learning, increased BBB permeability, and higher blood glucose compared to controls.
• Ketogenic diet effects on performance and BBB integrity correlated with ketone body levels, suggesting a protective role.
• Cognitive deficits in WD-fed rats preceded significant weight gain.

Conclusions:

• Western diets induce hippocampal-dependent cognitive deficits and compromise BBB integrity.
• Ketone bodies may offer neuroprotection against diet-induced cognitive impairment.
• Diet-induced cognitive impairment can precede obesity, highlighting early metabolic-neurological interactions.