Genetic variation in the murine lifespan response to dietary restriction: from life extension to life shortening.
Level 5 - mechanism / opinion, no new human data
Preclinical animal model study (CEBM Level 5).
PubMed 19878144 · doi:10.1111/j.1474-9726.2009.00533.x
What was done
Researchers measured the effect of a 40% dietary restriction (DR) regimen versus ad libitum (AL) feeding on the mean lifespan of virgin male and female mice across 41 recombinant inbred strains. They also assessed whether baseline AL food intake or female fertility correlated with survival under DR.
What was found
Mean strain-specific lifespan varied 2- to 3-fold under AL feeding and 6- to 10-fold under DR in males and females. DR shortened lifespan in more strains than it lengthened, though exact strain counts and survival numbers were not reported in the abstract. Neither baseline AL food intake nor female fertility predicted DR survival, and lifespans under AL and DR were not correlated.
Why it matters
This study demonstrates that the longevity response to dietary restriction is not universal across genotypes and can significantly shorten lifespan depending on genetic background.
Limits
The study tested only one fixed level of restriction (40%) in inbred laboratory mice, which may reflect severe caloric deficit rather than optimal restriction for some strains. Total animal count and exact lifespan values were not provided in the abstract. Findings cannot be directly generalized to humans.
Cited by
- supports Caloric restriction reliably extends lifespan in model organisms including yeast and fruit flies, but its effect on lifespan varies across different mouse strains.