Dietary benefits on epigenetic aging may largely reflect familial factors
A longitudinal study of Danish twins found individual-level dietary associations with biological age attenuated after controlling for shared genetics and early-life environment.
In a study of Danish monozygotic twins aged 18 to 67 years, researchers evaluated whether adherence to national dietary guidelines influences epigenetic aging over a 12-year follow-up. The team quantified diet using food frequency questionnaires and calculated epigenetic aging using DunedinPACE alongside several clocks, including PCHannum, PCHorvath1, PCPhenoAge, and PCGrimAge. In cross-sectional individual analyses, higher dietary adherence was associated with lower biological age, including 0.55 to 0.67 years lower PCGrimAge and a 3.1% slower pace of aging per index unit. However, these associations weakened considerably in within-twin-pair and longitudinal models that accounted for shared genes and early-life environmental factors. The researchers concluded that apparent dietary effects on epigenetic aging likely reflect familial confounding rather than strong independent associations.
Why it matters
Epigenetic clocks and pace-of-aging metrics are prominent tools for tracking biological aging. These findings highlight that familial confounding can heavily shape observational associations between lifestyle habits and molecular markers of aging.
Caveats
The study is observational and relied on food frequency questionnaires within a single Danish twin cohort. The results do not establish causal effects or rule out subtle dietary influences.
- Adherence to danish dietary guidelines
- Epigenetic alterations
- DNA methylation
- DunedinPACE
- PCGrimAge
- PCHannum
- PCHorvath1
- PCPhenoAge
- Homo sapiens
The paper
Dietary pattern and epigenetic aging: a longitudinal twin study
Nygaard M, Elliott HR, Smith GD et al.
GeroScience · 26 Sep 2026