A 67% reduction in dietary valine extended lifespan in male mice by 23%
A 67% reduction in dietary valine extended lifespan in male mice by 23%
On July 24, Nature Aging published a study of mice fed a lifelong diet beginning at four weeks of age. The researchers reduced only valine while keeping calories, fat, and carbohydrates unchanged. Median lifespan increased in males, and several health measures improved in both sexes.
Valine is an essential amino acid that the body must obtain from food. Together with leucine and isoleucine, it belongs to the BCAA group. In the Nature Aging study, the diet of C57BL/6J mice contained 67% less valine from four weeks of age. The researchers replaced the missing amount with amino acids that the body can synthesize.
This single dietary change affected several outcomes. Mice of both sexes gained less fat, regulated glucose more effectively, and had lower scores on the frailty index, a set of tests that measures age-related impairments. In males, median lifespan increased by 23%. Health measures improved in females, but lifespan did not change.
The authors also measured distinct responses in different tissues. Mice on the valine-restricted diet consumed more calories per unit of body weight and expended more energy at 18 months. Mitochondrial respiration increased in the livers of males. Their mitochondria converted energy from food more actively into molecules that cells use to support their functions. Females showed a larger reduction in the proportion of neuroinflammatory glial cells, which support neuronal function.
In a 2021 experiment, lifelong restriction of all three BCAAs extended lifespan in male mice by approximately 30%. The new study isolates the effect of valine from those of leucine and isoleucine. Changing this single component of the diet was sufficient to improve health measures in both sexes and extend lifespan in males. This approach allows researchers to compare how individual tissues respond to each amino acid instead of examining the effects of reducing all dietary protein at once.