Time-restricted feeding from adulthood to old age improves biconditional associative learning in geriatric rats regardless of macronutrient composition

Declining health and cognition are hallmarks of advanced age that reduce both the quality and length of the lifespan. While caloric restriction has been highlighted as a dietary intervention capable of improving the healthspan by restoring metabolic function in late life, time-restricted feeding and changes in dietary macronutrient composition may be more feasible alternatives with similar health outcomes. To investigate the potential of these two interventions, a pilot cohort of fully mature adult rats were placed on a time-restricted feeding regimen of a ketogenic or micronutrient and calorically matched control diet from 8 to 21 months of age. A third group of rats was permitted to eat standard chow ad libitum. At 22 months, all rats were then placed on time-restricted feeding and tested on a biconditional association task. While the data presented here are preliminary (small sample size of 3-4/diet group), additional animals are currently undergoing the feeding regimen, and will be added into the behavioral studies at a later date. For the current data, regardless of dietary composition, time-restricted-fed rats performed significantly better than ad libitum-fed rats. This observation could not be accounted for by differences in motivation, procedural or sensorimotor impairments, indicating that mid-life dietary interventions capable of preventing metabolic impairments may also serve to prevent age-related cognitive decline.