Hardly any field of research is developing as dynamically at present as so-called geroscience – the scientific study of biological aging processes.
In this context, biomarkers intended to map specific aspects of biological aging are increasingly being investigated.
Two major research projects have provided interesting data on this regarding vitamin D and omega-3 in recent years.
The VITAL Telomere Substudy
An analysis of the large-scale VITAL study was published in 2025.
Among other things, the length of so-called telomeres in white blood cells was investigated. Telomeres are structures at the ends of chromosomes whose length can change over the course of a lifetime. Over a period of four years, participants received, depending on the study group, 2,000 IU of vitamin D3 daily, marine omega-3 fatty acids, or corresponding control supplements. In the vitamin D group, a lower rate of telomere shortening was observed over the study period. For omega-3, however, this specific telomere analysis showed no comparable statistically significant effect.
This is an interesting research result – but it is not proof that vitamin D generally "slows down" the human aging process.
Telomere length is a biomarker and is not synonymous with lifespan or clinical health.
DO-HEALTH: Omega-3 and Epigenetic Clocks
Another study published in 2025 analyzed 777 participants from the European DO-HEALTH study.
In this study, so-called DNA methylation clocks were investigated. Over three years, vitamin D, omega-3, and an exercise program were compared individually and in various combinations. In three of the four primary epigenetic measurement methods examined, statistical changes were observed with omega-3. The magnitude was small overall. Combinations with vitamin D and exercise also showed additional effects in individual measurement procedures. Once again, the classification is crucial:
Epigenetic clocks are research tools. There is currently no single generally accepted "gold standard" that fully measures biological aging.
What is established for vitamin D
Independently of aging markers, vitamin D contributes to, among other things,
- the normal function of the immune system,
- the maintenance of normal bones,
- the maintenance of normal muscle function, and
- normal cell division
.
What is established for EPA and DHA
With a daily intake of at least 250 mg of EPA and DHA, EPA and DHA contribute to normal heart function.
With a daily intake of at least 250 mg, DHA additionally contributes to the maintenance of normal brain function and normal vision.
Conclusion
The VITAL and DO-HEALTH evaluations illustrate how sophisticated modern nutritional research has become.
It does not simply investigate whether a nutrient is "healthy," but rather measurable biological parameters over several years.
The results regarding telomeres and epigenetic clocks are scientifically interesting. However, they should not be equated with proof that a dietary supplement prevents or slows down the aging process.
The established functions of vitamin D, EPA, and DHA remain well-defined independently of this.
