Aging isn’t just about getting older—it’s also about how our bodies change on a deeper, biological level. Scientists have developed a concept called “epigenetic clocks,” which are like biological stopwatches that measure aging by studying DNA changes over time.
These clocks can show how fast a person ages, which can differ from their actual age in years. Slower biological aging means a longer, healthier life.
The DO-HEALTH Study
The DO-HEALTH trial, involving 2,157 older adults across Europe, examined whether vitamin D, omega-3 fatty acids, and exercise could slow biological aging.
Researchers focused on 777 participants, measuring their DNA before and after three years of taking supplements and doing home exercises. The goal was to see if these interventions could slow aging as measured by DNA methylation—chemical changes in DNA linked to aging.
Key Findings: Omega-3 Shows the Most Promise
Omega-3 had the three interventions’ most substantial effect on slowing biological aging. It helped reduce age acceleration in three different epigenetic clocks (PhenoAge, GrimAge2, and DunedinPACE).
This suggests that omega-3 might help keep the body younger at the molecular level. The study also found that vitamin D and exercise, when combined with omega-3, had additional benefits. However, they were not as strong when taken alone.
The Rigorous Methodology of the Study Participants were randomly assigned to different groups: some took 2,000 IU of vitamin D daily, others took 1 gram of omega-3, some did a simple home exercise program (SHEP) which included [specific exercises], and some did a combination of these. The study followed them for three years, regularly measuring their health and DNA changes.
Additive Benefits of Combined Treatments
While omega-3 alone had strong, clear benefits, combining it with vitamin D and exercise led to even better results. For example, people who took all three treatments showed improvements in PhenoAge, an epigenetic clock linked to disease and mortality risk. The combined treatments also demonstrated additional benefits.
Comparing DO-HEALTH to Other Aging Studies
Similar studies, like the CALERIE trial on caloric restriction, also found that lifestyle changes can influence biological aging. The DO-HEALTH study supports the idea that nutrition and exercise can play a key role in slowing down aging, especially at the molecular level.
Why These Findings Matter
Even small reductions in biological aging could lead to longer, healthier lives. If omega-3, vitamin D, and exercise can help delay the onset of diseases like cancer and frailty, they could significantly impact public health. This research suggests that simple lifestyle changes could help people stay biologically younger.

Best Sources For Omega-3s
Omega-3 fatty acids are essential for heart and brain health, and they come from both animal and plant sources. Fatty fish such as salmon, mackerel, sardines, anchovies, herring, and tuna are some of the best sources, providing high amounts of EPA and DHA—the most beneficial forms of omega-3s. Fish oil and krill oil supplements offer concentrated doses, while cod liver oil not only provides omega-3s but is also rich in vitamins A and D.
For those following a plant-based diet, several foods are excellent sources of ALA, a type of omega-3 that the body converts into EPA and DHA, though at a lower efficiency. Flaxseeds and flaxseed oil are among the richest plant-based sources, followed by chia seeds, walnuts, and hemp seeds.
Algal oil, derived from algae, is one of the only vegan sources that naturally contain EPA and DHA, making it a great alternative for those who do not consume fish. Other plant-based sources include edamame (soybeans) and seaweed varieties like nori, which provide small amounts of these essential fatty acids.
For optimal omega-3 intake, a balanced diet incorporating both fish-based and plant-based sources is ideal. Those who do not consume fish can still meet their omega-3 needs through supplements or by focusing on nutrient-rich plant sources.
Research Past and Future
An additional study published last year by the University of Georgia’s College of Public Health and Cornell University found a link between a higher ratio of omega-6 to omega-3 fatty acids and an increased risk of cancer and cardiovascular disease. Omega-6 oils are mainly found in Soybean oil, Corn oil, Sunflower oil, Cottonseed oil, and Safflower oil. Also found in margarine, mayonnaise, and many fried, fast foods.
According to the Georgia study, participants with the highest omega-6 to omega-3 ratios had a 26% higher risk of death from any cause, a 14% higher risk of dying from cancer, and a 31% greater likelihood of dying from heart disease compared to those with the lowest ratios. Bottom line: Stick with Omega-3s and avoid Omega-6 fats.
The DO-HEALTH study had some limitations. It only lasted three years, so it’s unclear if the benefits would last longer. Also, while epigenetic clocks are helpful, they don’t measure every aspect of aging. Future studies will need to explore long-term effects and include more diverse populations.
Omega-3s, Vitamin D And Exercise Offer a Healthier Future
The DO-HEALTH trial does indeed suggest that taking omega-3 supplements, getting enough vitamin D, and staying active could help slow aging at a biological level. While more research is needed, these simple lifestyle changes could be a nice step toward a longer, healthier life.