A nutritional memory effect counteracts benefits of dietary restriction in old mice.
Level 5 - mechanism / opinion, no new human data
Preclinical animal intervention study
PubMed 31742247 · doi:10.1038/s42255-019-0121-0
What was done
Researchers conducted a dietary switch experiment in 800 24-month-old female mice transitioning either from ad libitum (AL) feeding to dietary restriction (DR) or from DR to AL. Molecular mechanisms were investigated using RNA-seq profiling of liver, brown adipose tissue (BAT), and white adipose tissue (WAT), alongside characterization of aged preadipocytes.
What was found
Switching from DR to AL at old age acutely increased mortality. Conversely, switching from AL to DR caused only a weak and gradual increase in survival. Transcriptomic analysis showed that fat tissue, particularly WAT, exhibited a largely refractory transcriptional and metabolic response to late-onset DR. Chronic DR prevented an age-associated proinflammatory signature in preadipocytes that late-life DR failed to establish. No specific numerical survival rates, hazard ratios, or p-values were provided in the abstract.
Why it matters
This study demonstrates an adipose-tissue-based nutritional memory that constrains the longevity and metabolic remodeling benefits of dietary restriction initiated late in life in mammals.
Limits
The study was conducted exclusively in female mice, so findings may not generalize to males or humans. Exact quantitative survival metrics and effect sizes were omitted from the abstract.
Cited by
- supports Rodent studies show that the longevity benefits of caloric restriction are lost when the restriction is discontinued.