GrimAge, DunedinPACE, OMICmAge — the new biological age clocks (and which foods move them)

The original Horvath clock, published in 2013, was a landmark — the first demonstration that DNA methylation patterns could predict biological age independently of chronological age. But it was also blunt. It told you how old your cells looked. It said very little about where you were ageing, how fast you were ageing right now, or what was actually driving the process.

Thirteen years later, the field has moved considerably. We now have second and third-generation clocks that measure fundamentally different things — and understanding the distinction matters, because they respond to different interventions.

Three clocks in particular are reshaping how we think about biological age, food, and the window of opportunity that opens in your 40s.

GrimAge2 — the disease risk clock

GrimAge2 (an updated version of the original GrimAge clock) is a second-generation epigenetic clock designed not just to estimate biological age, but to predict mortality and disease risk. It does this by incorporating DNA methylation surrogates for plasma proteins associated with chronic disease — including PAI-1 (a marker of cardiovascular risk), leptin, and smoking-related damage.

In practical terms, GrimAge2 captures the accumulated biological consequences of your lifestyle and environment. A person with a GrimAge2 acceleration of +5 years does not simply “look” five years older at the molecular level — they carry a measurably increased risk of cardiovascular events, cancer, and all-cause mortality over the next decade.

What makes GrimAge2 especially relevant for women in perimenopause is its sensitivity to the homocysteine-methylation pathway. A 2026 paper in Alzheimer’s & Dementia (Li H et al.) found that elevated homocysteine concentrations were significantly associated with cognitive decline — and that GrimAge2 acceleration modified this relationship. In other words, high homocysteine was worse for cognition when biological age was also accelerated. The two compounded each other.

The intervention lever here is direct: folate, B12, B6, and betaine are methyl donors that reduce homocysteine by feeding the methylation cycle. Dark leafy greens, lentils, eggs, and liver are the strongest dietary sources. This is not theoretical — the methylation pathway is the mechanism by which GrimAge2 tracks disease risk.

DunedinPACE — the speedometer

If GrimAge2 tells you how much damage has accumulated, DunedinPACE tells you how fast the damage is currently accruing. Developed by the Dunedin Multidisciplinary Health and Development Study in New Zealand, it is calibrated against 19 biomarkers of organ-system decline measured longitudinally — tracking the rate of change rather than the static position.

A DunedinPACE score of 1.0 means you are ageing at the expected rate. Below 1.0, you are ageing more slowly than average. Above 1.0, faster. This makes it uniquely sensitive to recent lifestyle changes — including diet quality.

A 2026 study in GeroScience (Shen B et al.) examined DunedinPACE in 421 adults measured at two time points approximately five years apart. The finding was clear: lower diet quality — measured by both the Healthy Eating Index and the Dietary Inflammatory Index — independently accelerated DunedinPACE scores. This held after controlling for age, sex, poverty status, BMI, smoking, and physical activity.

This is significant because it demonstrates that overall dietary pattern, not any single nutrient, directly influences the speed of biological ageing. The foods that moved the needle were those rich in polyphenols, fibre, omega-3 fatty acids, and methyl donors — and the effect was dose-dependent.

In a 2024 trial published in Nature, omega-3 supplementation showed a small but significant protective effect on DunedinPACE over three years. The Fitzgerald et al. trial (2021) demonstrated that an 8-week diet, sleep, and exercise intervention decelerated DunedinPACE and reversed Horvath age by 3.23 years in men — using a food-first protocol built around the same methyl-donor and polyphenol-rich foods.

OMICmAge — the multi-layered clock

OMICmAge, published in Nature Aging in 2026, represents the newest generation: a clock that integrates multiple layers of biological data (DNA methylation, transcriptomics, proteomics, metabolomics, and electronic medical records) into a single ageing estimate. It does not rely on any single biomarker type but instead asks how all of these layers converge to describe biological age.

The landmark Cell 2026 paper by Li J et al. pushed this further by developing organ-specific clocks — separate ageing estimates for the brain, liver, lungs, muscles, blood vessels, and skin. Their most striking finding: organs age asynchronously. The liver reaches a critical ageing inflection point around age 40. The brain accelerates at around age 50. Two major nonlinear waves of ageing-related change occur between ages 40–50 and 60–70.

For women in perimenopause, this means your 40s are not simply a decade of hormonal transition — they are a decade of differential organ ageing, with the liver leading. The researchers also identified lifestyle factors associated with slower ageing across all organ clocks: greater fruit intake, consistent sleep routines, and regular walking. Smoking, insufficient sleep, and high meal frequency were associated with acceleration.

What this means for your plate

The three clocks converge on a consistent set of dietary priorities:

Methyl donors — folate (dark leafy greens, lentils, beetroot), B12 (eggs, fish, organ meats), B6, and betaine. These feed the one-carbon methylation cycle that GrimAge2 directly measures. A well-functioning methylation cycle keeps homocysteine low and supports the DNA methylation patterns these clocks track.

Polyphenol-rich foods — berries, green tea, extra-virgin olive oil, turmeric, dark chocolate (85%+). These influence DunedinPACE through anti-inflammatory and antioxidant mechanisms, reducing the rate of biological damage accrual.

Omega-3 fatty acids — oily fish (salmon, sardines, mackerel), walnuts, flaxseeds. The VITAL trial data showed omega-3 specifically slowed DunedinPACE over three years.

Fibre and plant diversity — 30+ different plant foods per week. This supports the gut microbiome, which produces butyrate — a short-chain fatty acid now shown to influence DNA methylation patterns directly. The Shah et al. 2026 paper in Cancer Discovery demonstrated that high-fibre dietary diversity improved butyrate production and downstream methylation markers.

Meal timing — the Cell 2026 data linked high meal frequency with faster organ ageing. Combined with the chrononutrition evidence showing that eating the final meal between 3pm and 7pm is linked to slower biological ageing, this suggests when you eat matters alongside what you eat.

The honest summary

These clocks are not perfect. They are still primarily research tools, and commercial biological age tests vary widely in which clock they use and how they interpret the results. If someone offers you a biological age test, the first question to ask is: which clock? The answer changes what the number means.

But the convergence of evidence is genuinely striking. Three different approaches to measuring biological age — accumulated risk (GrimAge2), speed of ageing (DunedinPACE), and multi-layered molecular integration (OMICmAge) — all point to the same dietary interventions: methyl donors, polyphenols, omega-3 fatty acids, plant diversity, and meal timing.

Your 40s are the decade when the liver clock accelerates, when methylation efficiency declines alongside oestrogen, and when the gap between chronological and biological age begins to widen most sharply. That is not a reason for alarm. It is a window — and the evidence suggests it responds meaningfully to what you put on your plate.

Read next: before trusting any single number, my guide to what deserves your attention in midlife health covers how to judge these claims calmly.