High energy diets prevent the enhancing effects of emotional arousal on memory.

Abstract

Over the past five decades, per capita caloric intake has increased by approximately 28% in the United States. Excessive intake of calories from fats and sugars (high energy diets; HEDs) negatively impacts hippocampal-dependent memory. These deleterious effects of HEDs on hippocampal function involve HED-induced decreases in neuronal growth factors, neurogenesis, and synaptic plasticity. Given that HEDs also alter responses to emotional arousal, the present experiment determined whether the effects of HEDs on memory depend on the emotional arousal produced by the memory task during encoding. Rats were fed a high fat/sugar cafeteria-style diet for 4 weeks and then tested in a low or high emotional arousal version of a spatial object place recognition task. The results demonstrated that the HED prevented the memory-enhancing effects of emotional arousal. Thus, altered responses to emotional arousal likely contribute to HED-induced memory impairments, particularly in stressful memory tasks such as the spatial water maze.

Impact of cafeteria feeding during lactation in the rat on novel object discrimination in the offspring

“…In contrast to the water-maze task, the NOD test does not involve high levels of stress or anxiety. In high-arousal memory tests, anxiolytic effects of hyperenergetic diets ( 29 ) can contribute to diet-induced memory impairment ( 30 ) . Our previous finding that lactational CD feeding programmes anxiolytic effects in the offspring ( 27 ) would therefore preclude the aversive water-maze task as a test of choice.…”