Dietary restriction impacts health and lifespan of genetically diverse mice.
Level 5 - mechanism / opinion, no new human data
Animal research (preclinical model)
PubMed 39385029 · doi:10.1038/s41586-024-08026-3
What was done
Researchers evaluated the effects of graded caloric restriction (20% and 40%) and intermittent fasting (1 and 2 days of fasting per week) on the health and survival of 960 genetically diverse female mice. They tracked survival alongside physiological, immunological, and metabolic traits to evaluate the interplay between genetics, dietary restriction regimens, and lifespan.
What was found
Caloric restriction (CR) and intermittent fasting (IF) both extended lifespan in proportion to the degree of restriction, with 40% CR showing the strongest lifespan extension. Lifespan was heritable, and genetics had a larger impact on lifespan than dietary restriction. Factors most strongly associated with longer lifespan were weight retention during handling stress, high lymphocyte proportion, low red blood cell distribution width, and high late-life adiposity. Metabolic improvements (reduced adiposity, lower fasting glucose) did not correlate with longer lifespan. Negative outcomes included lean mass loss and immune repertoire changes with 40% CR, disruption of erythroid cell populations with 2-day IF, and a lack of lifespan extension from IF in mice with high baseline body weight. Specific numerical survival times, percentages, and effect sizes were not reported in the abstract.
Why it matters
The study shows that metabolic improvements and lifespan extension decouple under dietary restriction in genetically diverse backgrounds. This suggests that conventional metabolic biomarkers may not be reliable surrogates for longevity interventions.
Limits
The study was conducted entirely in female mice, limiting generalizability across sexes and to human biology. The abstract reports no numerical survival statistics, effect sizes, or confidence intervals.
Cited by
- partial In mice, alternate-day intermittent fasting extends lifespan to the same extent as 30% caloric restriction without resulting in a permanent reduction in body weight.