A New Blood Test Offers Clues to Ageing and Longevity

A recent study has suggested that a simple blood or saliva test may soon provide an accurate indication of how well an individual is ageing—and how long they may live.

The research, published in Nature Aging, introduces an approach to measuring what is known as “intrinsic capacity”, a concept developed by the World Health Organization (WHO) to capture the full range of an individual’s physical and mental capabilities.

Intrinsic capacity (IC) is influenced by various factors including illness, injury, and biological ageing. It encompasses cognitive ability, mobility, sensory perception, emotional wellbeing, and vitality. Until recently, assessing IC required complex, time-intensive procedures involving specialised equipment and trained personnel.

Researchers have now developed what they term a DNAmIC test, which assesses DNA methylation—a chemical process that regulates gene activity—as a biological marker for IC. Their findings indicate that this test may offer a reliable means of evaluating how well a person is ageing in functional terms, as distinct from simply recording their chronological age.

The test was developed using data from over 1,000 individuals in the INSPIRE-T cohort, aged between 20 and 102 years. The researchers examined five domains of decline—cognitive, locomotor, sensory, psychological and vitality—and linked these with DNA methylation data obtained from blood and saliva samples. From this, they constructed what they call an “IC clock”, or epigenetic predictor of IC.

Participants with higher DNAm IC scores were found to have better lung function, stronger bones, quicker walking speeds and more positive self-perceptions of health. Furthermore, those in the highest IC category lived on average 5.5 years longer than those in the lowest. The researchers suggest that the DNAm IC test could become a practical tool for identifying individuals at greater risk of age-related decline, and for guiding interventions aimed at preserving physical and mental function.

Commenting on the findings, Dr Thomas Holland, physician-scientist at the RUSH Institute for Healthy Aging, described the DNAm IC test as a promising advance. “This test uses DNA methylation patterns to estimate your IC biologically, offering insights into how well your body is functioning compared to your chronological age,” he said. “If your body is functioning well internally, you are more likely to live longer and stay healthier.”

Unlike earlier epigenetic clocks, which estimate biological age in general terms, the DNAm IC test is said to reflect functional age more directly. Elena Rolt, a registered nutritional therapist, stated that the test “may be particularly relevant for personalised ageing interventions and preventive strategies”, noting that it captures not only epigenetic ageing but also immune health and lifestyle-related risk factors.

However, both Holland and Rolt emphasised that the test must be used alongside other diagnostic tools—such as GrimAge and PhenoAge markers—and will require further clinical validation, particularly among older adults with low IC.

In exploring the relationship between lifestyle and DNAm IC, the study identified two dietary factors associated with better IC scores: high intake of oily fish and low consumption of added sugar. These findings are consistent with previous research linking diet to age-related outcomes.

Dr Tunç Tiryaki, founder of the London Regenerative Institute, explained that omega-3 fatty acids found in oily fish help reduce inflammation and support mitochondrial and cognitive function. He also warned against excessive sugar consumption, which contributes to insulin resistance and oxidative stress—both implicated in age-related decline.

The study authors and external commentators alike suggested that regular monitoring of DNAm IC could inform efforts to extend not only lifespan but healthspan—the number of years lived in good health.

To that end, experts recommend a multi-faceted approach to healthy ageing. These include:

• A balanced diet rich in fresh produce, wholegrains, and healthy fats, following models such as the Mediterranean or MIND diet;

• Regular physical exercise, incorporating both cardiovascular and strength training, to support vitality and mobility;

• Cognitive and social engagement, which are linked to better psychological resilience and cognitive preservation;

• Effective management of stress and chronic medical conditions.

Holland noted that the DNAm IC test represents a significant shift in the field of ageing research. “It links molecular biology with real-world outcomes like mobility, cognition and lifespan. While further validation is needed, especially in older adults, this study lays the groundwork for using personalised epigenetic markers to guide interventions in preventive geriatrics and public health.”

In summary, while the DNAm IC test is not yet ready for widespread clinical deployment, it appears to offer a scientifically grounded method for gauging how well an individual is ageing and what might be done to preserve function. If further validated, it could become a valuable tool in the emerging field of longevity medicine.

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