Amino-acid imbalance explains extension of lifespan by dietary restriction in Drosophila.
Level 5 - mechanism / opinion, no new human data
Bench and animal model research (Drosophila melanogaster)
PubMed 19956092 · doi:10.1038/nature08619
What was done
Investigators tested whether the trade-off between lifespan extension and fecundity under dietary restriction is driven by competitive reallocation of limiting nutrients in Drosophila melanogaster. They added essential amino acids or methionine alone to dietary restriction regimens and evaluated the resulting changes in lifespan, fecundity, and insulin/insulin-like growth factor signaling pathways.
What was found
The abstract reports no numerical values, statistical metrics, or sample sizes. Qualitatively, adding essential amino acids to dietary restriction diets increased fecundity and reduced lifespan, mimicking full feeding. Methionine supplementation alone increased fecundity to levels seen in full feeding without reducing lifespan. In addition, reduced insulin/insulin-like growth factor signaling protected against full-feeding-induced lifespan reduction.
Why it matters
This study challenges the standard evolutionary theory that dietary-restriction lifespan extension necessitates an obligatory trade-off against fecundity via nutrient reallocation. It shows that longevity and reproduction can be decoupled by manipulating individual amino acids, particularly methionine.
Limits
The findings are from an invertebrate laboratory model (Drosophila) and may not generalize to mammals or humans. The abstract reports no numerical data, effect sizes, survival metrics, or sample sizes.
Cited by
- supports Essential amino acids such as methionine increase fecundity but are negatively associated with longevity.