Intermittent fasting is a broad term that describes periods of fasting between meals, lasting several hours to days. Intermittent fasting increases ketone production because it uses stored fat as an energy source. It also activates genetic pathways associated with enhanced healthspan and longevity. Caloric restriction, which typically involves a 10 to 40 percent reduction in total caloric intake, activates similar pathways. Findings from a new study suggest that intermittent fasting is more effective than caloric restriction in activating klotho, a longevity gene, to improve long-term memory retention in mice.
The klotho gene provides the instructions for making the klotho protein in mammals, including mice and humans. Klotho is produced primarily in the kidneys, but some is produced in the brain, where it appears to play a role in cognition and in neurogenesis, the process of forming new neurons. Neurogenesis is the basis for memory, but it declines with age, leading to cognitive decline.
The authors of the study assigned mice to one of three feeding regimens: intermittent feeding every other day (approximately 10 percent fewer calories over a one-week period); 10 percent calorie restriction; or eating freely. After the mice had followed their respective feeding regimens for three months, the authors of the study subjected them to behavioral studies (to assess spatial learning and memory, conducted at 24 hours and ten days post regimen) or gene expression studies.
The memory assessment conducted at 10 days post regimen revealed that the mice in the intermittent feeding group performed 25 percent better than those in the caloric restriction group and 30 percent better than those that ate freely. The mice in the intermittent feeding group also exhibited more signs of hippocampal neurogenesis and upregulation of the klotho gene. Further analysis revealed that adult hippocampal neurogenesis is dependent upon klotho activity.
These findings demonstrate that the longevity gene klotho is necessary for neurogenesis and that intermittent feeding may be beneficial in promoting memory retention in humans. A ketogenic diet also improves memory in mice. Learn more in this episode featuring aging expert Dr. Eric Verdin.
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