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Caloric restriction increases longevity substantially only when the reaction norm is steep
John P Phelan1, Michael R Rose
1Life Sciences Core Program, University of California, Los Angeles, CA 90095-1606, USA. jay@ucla.edu
Biogerontology
|July 22, 2006
Summary
Evolutionary theory suggests dietary restriction increases lifespan. However, human caloric restriction likely offers minimal benefits due to evolved, flat longevity reaction norms, unlike rodents.
Area of Science:
- Evolutionary biology
- Gerontology
- Mammalian physiology
Background:
- Evolutionary theory predicts dietary restriction enhances survival and lifespan.
- Reaction norms quantify environmental effects on traits like longevity.
- Rodent longevity shows a steep response to caloric intake.
Purpose of the Study:
- To investigate the evolutionary divergence of dietary reaction norms between rodents and humans.
- To assess the potential for lifespan extension in humans through caloric restriction.
Main Methods:
- Comparative analysis of dietary reaction norms across species.
- Utilizing evolutionary principles and existing experimental data.
- Estimating the quantitative relationship between caloric intake and longevity in humans and rodents.
Main Results:
- Dietary reaction norms are expected to evolve for fitness-related traits.
- Rodent longevity reaction norms are steep, while human norms are estimated to be very flat.
- Divergence in dietary reaction norms between rodents and humans is substantial.
Conclusions:
- The strong link between caloric intake and longevity in rodents is not conserved in humans.
- Human longevity shows a minimal response to changes in caloric intake.
- Substantial lifespan increases from caloric restriction are unlikely in humans.