Limiting dietary isoleucine, an amino acid, boosts metabolic health, reduces frailty, and extends lifespan in genetically diverse mice, especially males. Starting this restriction in mid-life enhances healthspan without calorie reduction, suggesting that protein quality, specifically amino acid composition, may be crucial for promoting healthy ageing and increasing longevity.
November 2023 – Cell Metabolism
Key takeaways
- Mid-life dietary change boosts longevity: Reducing isoleucine from the diet starting at mid-life significantly increased median and maximum lifespan in male mice and modestly extended median lifespan in females. This demonstrates that interventions to promote healthy ageing can still be effective when initiated in adulthood, without needing to reduce overall calorie intake
- Improved metabolic health across ages: Isoleucine restriction enhanced metabolic health in both young and old mice, improving glucose control, reducing fat mass, and increasing energy expenditure. These effects occurred despite increased calorie intake, highlighting a potent metabolic shift driven by amino acid balance rather than energy restriction
- Sex-specific longevity effects observed: The benefits of isoleucine restriction were more pronounced in males, with stronger impacts on lifespan extension and reduced tumour incidence. Molecular analysis revealed sex-dependent metabolic and genetic responses, indicating that personalised approaches based on sex may optimise dietary strategies for healthy ageing
- Isoleucine matters more than protein quantity: Compared to general protein restriction, targeted isoleucine reduction produced greater improvements in lifespan and metabolic function. This highlights that not all proteins or amino acids are equal in ageing outcomes, suggesting a shift in focus toward protein quality and amino acid composition for wellness and longevity interventions
Read the article at: Green, Cara L., et al. “Dietary restriction of isoleucine increases healthspan and lifespan of genetically heterogeneous mice.” Cell Metabolism, vol. 35, 2023, pp. 1976–1995. https://doi.org/10.1016/j.cmet.2023.10.005.
