Can Omega-3 Fatty Acids Slow Aging?

This Week’s Research Highlight

Aging and the passage of time are inexorable. Yet we all know that not every individual ages in the same way. Two people can be exactly the same age, yet one might be aging faster than the other — not on paper, but deep beneath the surface.

That’s the premise behind biological age, a measure of how well (or poorly) the body is holding up over time. Unlike the date on a birth certificate, biological age reflects hidden wear and tear at the cellular level. The faster it accelerates, the greater the risk of impending disease, frailty, and premature death.

But what if you could slow it down?

A new study — led by Steve Horvath, a pioneer in aging research — puts this idea to the test. By examining how omega-3s, vitamin D, and exercise influence biological aging, this research offers a rare, ultra-rigorous perspective on whether basic lifestyle interventions can actually shift the course of aging itself.

How They Tested It

To determine whether lifestyle interventions can slow biological aging, researchers used DNA methylation clocks — computational models that estimate biological age based on specific epigenetic markers — as well as a biomarker-based aging clock.

The DO-HEALTH Bio-Age trial followed 777 healthy older Swiss adults (average age: 75) over three years.

Participants were randomly assigned to one of eight groups to test how omega-3s, vitamin D, and exercise, alone or in combination, impacted the aging process:

• Control group: Performed static stretching (placebo exercise).
• Omega-3 group: Took 1 gram of omega-3s daily
• Vitamin D group: Took 2,000 IU of vitamin D3 per day.
• Exercise group: Completed a home-based resistance training program three times per week.
• Combination groups: Some participants received multiple interventions to test for additive effects:
• Omega-3 + Vitamin D
• Omega-3 + Exercise
• Vitamin D + Exercise
• Omega-3 + Vitamin D + Exercise

By tracking these interventions over three years, researchers could evaluate both their individual effects on biological aging and whether combining them led to greater benefits.

More info on the aging clocks used in this study

• PhenoAge: This clock estimates biological age based on blood biomarkers linked to inflammation, immune function, and metabolic health. Because it reflects systemic aging processes, it is strongly predictive of disease risk, functional decline, and mortality.
• GrimAge: A DNA methylation-based clock designed to predict lifespan and chronic disease risk. It incorporates markers associated with smoking history and key proteins like PAI-1 and GDF-15, which are linked to cardiovascular disease, cancer, and mortality.
• GrimAge2: An improved version of GrimAge with enhanced accuracy. By incorporating additional aging-related proteins and refining its methylation models, it offers a more precise estimate of mortality risk while reducing measurement variability.
• DunedinPACE Clock: Unlike the other clocks, DunedinPACE doesn’t estimate biological age — it measures the speed of aging in real time. It tracks how fast physiological decline is occurring, making it particularly useful for assessing short-term interventions and lifestyle changes.

What Did They Find?

Omega-3 supplementation was the only intervention that consistently slowed biological aging.

Across three of the four clocks (PhenoAge, GrimAge2, and DunedinPACE), participants taking omega-3s showed a modest but measurable reduction in biological aging over the three year study period. The impact of supplementation was largest, as you might expect, among individuals with low baseline levels of omega-3 fatty acids.

But here’s where it gets interesting: the strongest effects emerged when omega-3s were combined with vitamin D and exercise. Notably, this combination had the greatest impact on PhenoAge, which reflects systemic aging processes such as inflammation, immune function, and metabolic health.

This suggests that these interventions attack different aspects of aging in a complementary fashion:

• Omega-3s reduce inflammation and support cardiovascular health.

• Vitamin D strengthens immune function and cellular repair.

• Exercise enhances muscle mass, metabolic health, and overall resilience.

Together, they may create a more robust defense against aging than any single intervention alone.

How Each Aging Clock Responded

The effects of omega-3s weren’t uniform across all four clocks, revealing which aspects of biological aging they influence most.

(Quick note: SHEP means Simple Home Exercise Program)

PhenoAge: The Strongest Response

Omega-3s slowed biological aging in this clock. The biggest effect was seen when combined with vitamin D and exercise.

Why does this matter? Since PhenoAge is built on clinical biomarkers (CRP, WBC count, albumin, etc.), these results suggest that omega-3s don’t just alter DNA methylation — they influence broader metabolic and immune aging processes.

GrimAge: No Clear Impact

No significant reduction in biological aging was observed, and adding vitamin D or exercise didn’t enhance the effect.

Why might this be? Hard to say, but one thing to keep in mind is that GrimAge is heavily weighted toward long-term mortality risk factors, which might not respond as rapidly to relatively short-term interventions.

GrimAge2: A Modest, Consistent Benefit

Omega-3 supplementation slowed biological aging, albeit modestly. No additional benefits were observed when combined with other interventions.

DunedinPACE: Slowing the Speed of Aging

Omega-3s were effective here, though the effect was fairly small — about a 1% reduction in the pace of aging. No additional benefit was seen from combining interventions.

How Omega-3s Influence Key Aging Biomarkers

Beyond slowing biological aging, omega-3 supplementation also lowered blood markers linked to inflammation, metabolic dysfunction, and mortality.

These proteins — measured using the GrimAge clock — act as early warning signs of accelerated aging and chronic disease risk.

So what specifically did omega-3s change?

• PAI-1 (Plasminogen Activator Inhibitor-1) – A key driver of metabolic dysfunction. High levels are linked to insulin resistance, blood clot risk, and shorter lifespan. Lowering PAI-1 suggests improved metabolic and cardiovascular health.

• Leptin – A hormone that regulates appetite and metabolism. High levels indicate leptin resistance, which contributes to obesity and metabolic dysfunction. Lower leptin suggests better energy regulation.

• TIMP-1 – A protein linked to tissue remodeling and chronic inflammation. Lowering TIMP-1 may reduce age-related fibrosis and inflammatory stress.

• B2M (Beta-2-Microglobulin) – A marker of immune system aging. High levels are associated with frailty, cognitive decline, and chronic disease risk. Lower B2M suggests a slower rate of immune aging.

• GDF-15 (Growth Differentiation Factor-15) – Often called a “stress response protein,” GDF-15 increases with chronic disease and aging. High levels correlate with frailty, inflammation, and a shorter lifespan. Lower levels suggest greater resilience to age-related decline.

When combined with other interventions, we see even stronger effects:

• Omega-3 alone lowered PAI-1, leptin, and TIMP-1, reflecting its effects on metabolic and inflammatory pathways.

• When combined with vitamin D and exercise, it also reduced B2M and GDF-15, suggesting a broader systemic impact on immune function and stress response.

• Rather than targeting a single mechanism, this combination appears to act across multiple biological pathways.

Final Takeaways

Dietary omega-3s may slow biological aging — especially in those with low baseline levels.

In this trial, three of the four aging clocks showed a measurable benefit from supplementation, reinforcing that targeted nutritional strategies can influence molecular aging.

But the most compelling finding wasn’t the effect of omega-3s alone — it was the greater impact seen when combined with vitamin D and exercise. Instead of searching for a single “anti-aging” solution, this study lends support to a multi-faceted approach: targeting inflammation, metabolic function, and immune resilience all at once.

Are these aging clocks actually meaningful?

One of the most interesting aspects of this study is how the strongest response (seen in PhenoAge) appears to align with clinical outcomes. In previous DO-HEALTH findings, the same combination of omega-3s, vitamin D, and exercise reduced signs of frailty by 39% and invasive cancer risk by 61%.

This suggests that biological aging clocks aren’t just abstract molecular measures — they may be capturing real-world health outcomes, and slowing biological aging could translate into tangible health benefits.

How much omega-3 is needed to achieve these benefits?

In this study, participants took 1 gram of omega-3s daily (660 mg DHA, 330 mg EPA). While this is a reasonable starting point for most people, individual needs may vary. One way to assess your own omega-3 status is through the Omega-3 Index, a blood test that measures EPA and DHA levels in red blood cells. (Scroll down for more info about that!)

Ultimately, the most important takeaway here isn’t merely about omega-3s. It’s that aging isn’t set on a fixed trajectory. The choices we make can meaningfully shape how we age, and some of the most impactful interventions are also the simplest.

Summary: This study examined whether omega-3 fatty acids, vitamin D, and exercise could slow biological aging in older Swiss adults. Omega-3 supplementation (660mg DHA + 330mg EPA daily) showed modest but positive effects on biological aging markers, particularly in those with low omega 3 and vitamin D levels. While vitamin D and exercise alone didn't significantly impact aging markers, combining them with omega-3s produced better results.

Random Trivia & Weird News

Art by William Clark - Missouri History Museum. Gallery, Public Domain

🔥  The eulachon (aptly known as the candlefish) is so packed with omega-3s that indigenous peoples once dried them, stuck a wick in their mouths, and used them as makeshift candles.

When set ablaze, these fish burned with a steady flame, providing light on dark nights. But the candlefish has another weird trait: it smells like fresh cucumbers when alive. Fishermen navigating cold coastal waters could sometimes detect the fish before seeing them, thanks to their oddly refreshing scent.

Beyond its quirky smell and flammability, the eulachon was incredibly valuable. Known as “grease trails,” ancient trade routes were established just to distribute its prized oil, which was used for cooking, medicine, and waterproofing. The fish was so rich in fat that even animals know its worth— bears, otters, and eagles all compete for this omega-3 powerhouse when it returns to spawn.

Today, candlefish populations have declined, but its legend lives on as one of the few creatures in history to serve as both a meal and a natural lantern. Smells like cucumbers, burns like a candle. Nature is wild.

Check out this 2 min 04 sec video on YouTube from National Geographic to learn more

Podcasts We Loved This Week

• Marie-Pierre St-Onge: Diet and sleep interactions. Via Sigma Nutrition.

• Greg Potter: Could the sauna extend your life and boost your health and fitness? Via Reason & Well-being

Products We Like

Omega Quant Omega-3 Index Complete - Complete Fatty Acid Profile Blood Test Kit 

The Omega-3 Index Complete test offers a comprehensive look at your fatty acid profile, measuring key markers that influence cardiovascular and metabolic health, including:

• Omega-3 Index – A higher percentage (8-12%) is linked to better cardiovascular and cognitive function.
• Trans Fat Index – Elevated levels are associated with an increased risk of heart disease.
• Omega-6:Omega-3 Ratio – An imbalance may contribute to chronic inflammation.
• AA:EPA Ratio – A key indicator of inflammatory balance in the body.

Since fatty acid levels respond to diet and lifestyle changes within 3-4 months, this test helps you fine-tune your diet and supplementation based on real data rather than guesswork. Best of all, this test couldn’t be easier — just collect your sample at home, mail it in, and you should receive your results in 1-2 weeks.

humanOS Catalog Feature of the Week

Almond-Crusted Petrale Sole with Roasted Asparagus

From the Primary Paleo Recipe Pack

This crispy pan-fried petrale sole with roasted asparagus is a simple, flavorful way to get your omega-3s without much effort. A light almond meal coating creates a satisfying crunch while keeping the dish gluten-free, and briny capers add a bright, savory contrast. Paired with tender, roasted asparagus, this meal delivers protein, healthy fats, and fiber — all in under 30 minutes.

To Access:

1. login to humanOS
2. See Recipes in navigation
3. Primary Paleo Recipe Pack
4. See the recipe inside!

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Wishing you the best,