# β-hydroxy-β-methylbutyrate Attenuates Age-Dependent Loss of Flight Ability and Extends Lifespan in Drosophila

## TL;DR

This study shows that HMB improves flight ability and extends lifespan in fruit flies by enhancing muscle health as they age.

## Contribution

The study demonstrates HMB's long-term benefits on muscle function and lifespan in Drosophila when consumed throughout adult life.

## Key findings

- HMB supplementation significantly improved flight scores in both male and female flies.
- HMB extended lifespan without affecting food consumption or body weight.
- Old flies on HMB retained more youthful muscle mitochondria morphology.

## Abstract

β-hydroxy-β-methylbutyrate (HMB) has been shown to enhance muscle function and strength in older humans and rodents after periods of consumption extending for several weeks. We investigated the feasibility of utilizing Drosophila as a model organism to study the biological effects of HMB on aging muscle when consumed throughout adult life. Using flight ability as an index of flight muscle function, we found that HMB attenuates the age-dependent decline in flight ability. Male and female flies fed a diet supplemented with 10 mg/mL HMB had significantly higher flight scores from median age until the onset of flight senescence than control flies fed a standard diet. HMB supplementation also resulted in improved flight scores in males before median age and delayed the onset of flight senescence in females. Notably, the consumption of HMB throughout adult life increased the rate of survival and extended lifespan. The effect on lifespan did not result from changes in food consumption or body weight. Old flies on the HMB-supplemented diet retained a higher proportion of flight muscle mitochondria whose morphology resembled that of young flies than the control diet group. Together, these results suggest that HMB attenuates the age-dependent decline in flight ability and prolongs lifespan by enhancing muscle health.