Fish Oil & VD3 Reverses Aging? Science Says Yes.

Written by

Louise W Lu, PhD, MPH, BMLS

Reviewed by

Alexandra V Goldberg, Registered Dietitian

What if aging didn’t have to follow a fixed timeline?

What if the pace of decline—inside your cells—could actually be slowed, with something as simple as a daily nutrient?

That’s not just a hopeful thought—it’s what researchers uncovered in a remarkable three-year clinical trial, recently published in Nature Aging. Involving 777 healthy adults aged 70 and over across five European countries, the study showed that a daily dose of Omega-3 fatty acids helped slow biological aging, as measured by changes in DNA methylation—one of the most reliable indicators of how fast we’re truly aging.

And it gets better: the benefits were even greater when Omega-3 was paired with Vitamin D3 and regular, low-intensity exercise.

If you’re over 40 and looking for a simple, science-backed way to age better—not just on the outside, but deep within—this might be the most valuable five minutes you spend all week.

Why You Might Be Biologically Older (or Younger) Than You Think

Have you ever met someone who’s 50 but looks 38? Or someone who’s 60 but moves and thinks like they’re still in their 40s?
You might’ve wondered: “How is that possible?”

It actually is—because we all have more than one age.

There’s the age on your birth certificate—your chronological age—which is just the number of years you’ve lived.
But then there’s your biological age—a reflection of how your body is actually functioning.

It’s based on how well your cells repair, how fast your tissues age, how strong your immune system is, and how your organs are holding up. And unlike your birthdate, your biological age can be younger—or older—depending on your lifestyle, stress, sleep, and even mindset.

Now here’s where things get really interesting:
Scientists have found a way to measure biological age by looking deep inside your DNA. It’s called your epigenetic age.

Epigenetic age is based on changes that affect how your genes behave—not by changing the genes themselves, but by adjusting how “active” they are.

The most well-studied marker for this? Something called DNA methylation—tiny chemical tags that tell your body which genes to turn on, and which ones to silence.

These changes accumulate as you live: from what you eat to how you move, how you sleep, how much inflammation you carry, and even how often you feel joy or stress.

And the best part?
Unlike your birthdate, you can change it.

The DO-HEALTH Study—How Omega-3, Vitamin D3 & Exercise Slow Aging Together

So—can we really change our epigenetic age?

A major clinical trial says yes.

In a large-scale, 3-year randomized controlled trial called DO-HEALTH, researchers followed 777 generally healthy, active adults over age 70 across five European countries. Participants were split into different groups to test the effects of:

• Omega-3 supplements (1 gram/day) — providing 333 mg of EPA and 667 mg of DHA, in a 1:2 ratio
• Vitamin D3 (2,000 IU/day) — in the form of cholecalciferol, the body’s natural and most bioavailable type
• A simple home-based exercise program (twice weekly)
• Or combinations of the above

Their goal? To see if these low-risk, everyday interventions could slow biological aging—measured by DNA methylation clocks.

What they found was modest—but meaningful:

• The combination of Omega-3 + Vitamin D3 + light exercise slowed epigenetic aging by 2.9 to 3.8 months over 3 years, based on PhenoAge DNA methylation clocks
• No single intervention alone had a statistically significant effect—but combined, they showed measurable biological impact
• All interventions were safe, easy to maintain, and well tolerated by older adults

Imagine this: if you start taking Omega-3 and Vitamin D3 and stay lightly active from your mid-30s, by the time you turn 60, your body could be functioning at least 2–3 years younger than your actual age—not just on the outside, but deep down in your cells, your organs, and your DNA.

How to Choose—and Use—Omega-3 and VD3 for Anti-Aging

So you’ve decided to start using Omega-3 and Vitamin D3. But not all supplements—and not all routines—are created equal.

How to use Omega-3 throughout the day:

Morning routine:

• Take a high-EPA Omega-3 supplement (e.g. 500–600 mg EPA)
• Helps reduce inflammation and support healthy cortisol rhythm
• Supports alertness and daytime energy

Evening routine:

• Take a high-DHA Omega-3 supplement (e.g. 600–800 mg DHA)
• Supports overnight brain repair and nerve regeneration
• Promotes cellular recovery and gene expression balance

How to use Vitamin D3 throughout the day:

The DO-HEALTH study used 2,000 IU of cholecalciferol (Vitamin D3), the natural form your skin produces from sunlight—and the most bioavailable form for supplements.

For best absorption:

• Take Vitamin D3 with your main meal of the day (usually breakfast or lunch)
• Avoid taking it late at night, as it may slightly reduce melatonin production
• Choose micro-encapsulated D3 whenever possible. This improves stability, enhances gut absorption, and ensures a steady release that mimics how your body would process sun-exposed D3 naturally.

It’s simple. It’s backed by science. And if you stick with it, you’re not just supplementing—you’re shaping how your body ages.

Final Thoughts

Slowing down aging doesn’t require complicated routines or expensive therapies.

As the DO-HEALTH trial shows, a few small, consistent actions—like taking Omega-3 and Vitamin D3, and moving your body a few times a week—can make a measurable difference in how your cells age.

This isn’t about chasing youth. It’s about protecting function. About having the energy to do what you love, stay independent longer, and age on your own terms.

You don’t have to do everything perfectly. But if you start today—and stick with it—your future self will thank you.

Authors:

Louise W Lu

Registered Nutritionist (NZ Reg. 82021301), PhD of Nutrition Science, Honorary Academic at the University of Auckland. Louise blends clinical research with public health to help people eat better and live stronger.

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Alexandra V Goldberg

Registered Dietitian (NZ Reg. 20-02273) and expert in nutrition, medicinal chemistry, and skincare. Alexandra helps clients reach their health goals with science-backed strategies in post-op recovery, feeding tolerance, and weight management.

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