Two people can share a birthday and still be ageing at different rates.
For a long time, this difference was attributed to luck, genetics, or talk of “ageing well”. Researchers can now measure differences in the pace of biological ageing, opening up new questions about whether lifestyle and dietary interventions can influence it. Emerging research involving a specific strain of gut bacteria studied by Morinaga Milk Industry offers an early signal that such interventions may affect measurable markers of biological ageing.
From age in years to age in biology
Chronological age counts birthdays. Biological age reflects the cumulative changes taking place across a person’s cells, tissues and organ systems, which can diverge from their chronological age. Researchers have developed increasingly sophisticated ways to quantify this difference, including measures based on DNA methylation.
Scientists can estimate biological age using DNA methylation, a chemical modification that helps regulate gene activity. The human genome contains millions of sites where these modifications can occur, and researchers have used statistical and machine-learning approaches to identify patterns that correlate with age and health.
The first generation of epigenetic clocks, including the Horvath and Hannum clocks, estimated biological age directly from DNA methylation data. A newer generation, including PhenoAge and GrimAge, was built to predict health outcomes and mortality risk rather than age alone. DunedinPACE represents a further shift in focus: rather than estimating how old a person is biologically, it is designed to estimate the pace at which they are ageing.
Developed using data from New Zealand’s long-running Dunedin Study, it uses DNA methylation patterns measured from a blood sample to provide an estimate of the pace of ageing.1
Why pace matters more than chronological age
If ageing has a measurable pace, the question becomes which biological processes are associated with changes in that pace. In 2023, an expanded framework of the hallmarks of ageing identified twelve interconnected hallmarks, from genomic instability to cellular senescence.2
The abundance of Bifidobacterium decreases with ageing, and this decline is associated with an increased risk of various diseases. Meanwhile, most studies indicated that bifidobacteria is linked to these hallmarks by indirect evidence limited to cellular or animal experiments.
This has prompted growing interest in whether changes in the gut microbiome by using probiotic supplementation may be associated with biomarkers of biological ageing, rather than focusing solely on digestive health.
The study: Can a yogurt containing B. longum BB536 and lifestyle intervention influence ageing pace?
Morinaga researchers have contributed to research in this area through a randomised, exploratory trial published in the journal Aging in May 2026.3 The study randomised 48 overweight men aged 50 to 74 with a BMI of 25 or higher to either an intervention or a control group.
The multimodal intervention combined daily consumption of yogurt containing BB536, a specific strain of the probiotic bacterium Bifidobacterium longum, with dietary counselling and exercise. The aim was to allow researchers to explore whether the programme was associated with changes in DNA methylation-based measures of ageing.
Specifically, the intervention group followed a three-month multimodal programme combining daily consumption of 100g of plain yogurt containing BB536, individualised dietary counselling based on food records, and at least 30 minutes of moderate-intensity exercise on three or more days per week. The control group was asked to continue their usual dietary and lifestyle habits.
At the end of three months, the intervention group showed a significant decrease in DunedinPACE compared to the control group, suggesting the pace of biological ageing may have slowed by approximately 2.3%.
In exploratory correlation analyses, the change in DunedinPACE was not significantly associated with changes in BMI or exercise frequency. However, because the intervention combined daily consumption of BB536-containing yogurt with dietary counselling and structured exercise, the study cannot determine which component, or combination of components, accounted for the change.
The findings therefore provide an early signal associated with the multimodal intervention and support further research into the specific contribution of BB536 to biological ageing.
For context, the study’s authors note that a 2.3% shift is broadly comparable in magnitude to the roughly 2% to 3% reduction in ageing pace reported in a US trial in which participants were assigned a caloric-restriction target of 25% for two years.4
Potential mechanisms behind the results
If the BB536-containing yogurt intervention contributed to the change observed in the trial, the next question is how. Two strands of research offer potential biological explanations, each pointing to a different pathway.
The first concerns inflammation. A 2026 study provides one possible link between bifidobacteria and inflammatory regulation. Researchers found that higher levels of gut bifidobacteria were associated with lower inflammatory responses in immune cells derived from healthy participants’ blood. In laboratory experiments, exposure to bifidobacteria-derived components shifted innate immune cells toward a less inflammatory response model when the cells were challenged by bacterial stimuli. This effect was associated with changes in histone methylation and alterations in inflammation-related and metabolic pathways, suggesting a potential mechanism for the observed immune modulation.5
The second line of research focuses on renal protection, another factor influence the pace of ageing. Experimental research shows some bifidobacteria , especially BB536 can largely convert indole into indole-3-lactic acid, a metabolite associated with immune regulation, competitively reducing the indole-indoxyl sulfate pathway in liver, lighten the burden of kidney potentially.6
Together, these two lines of research suggest that bifidobacteria may influence biological processes relevant to ageing, including inflammatory responses and microbial metabolism. While the studies do not establish how the multimodal intervention affected DunedinPACE, they provide potential pathways for further investigation.
From ageing pace to healthspan
The BB536 findings offer an early signal that a familiar, everyday dietary intervention may be a simple and practical approach to positively influencing the pace of biological ageing. Biological ageing has traditionally been attributed to genetic predisposition and chance, but epigenetic clocks like DunedinPACE are beginning to show that some portion of that variation may be responsive to specific, identifiable inputs, including the composition of the gut microbiome.
The result also points toward a broader shift already underway in ageing science: attention moving from lifespan toward healthspan, from simply living longer to living well for longer. For Morinaga, the findings underscore the importance of continuing research into the relationship between the gut microbiome, diet and biological ageing, while further clinical studies needed to be conducted to validate the anti-inflammatory effect and elucidate the precious mechanism of maintaining healthy ageing.
References
- Belsky, DW.; et al. DunedinPACE, a DNA methylation biomarker of the pace of aging. eLife. 2022;11. e73420.
- López-Otín, C.; et al. Hallmarks of aging: an expanding universe. Cell. 2023;186(2):243–278.
- Nishimura, T.; et al. Short-term responsiveness of DNA methylation-based aging biomarkers to a multimodal intervention comprising exercise and dietary guidance involving daily consumption of yogurt containing Bifidobacterium longum BB536: an exploratory randomized controlled trial. Aging (Albany NY). 2026;18:639–655.
- Waziry, R.; et al. Effect of long-term caloric restriction on DNA methylation measures of biological aging in healthy adults from the CALERIE trial. Nature Aging. 2023;3(3):248–257.
- Ishihara, S.; et al. Gut commensal bifidobacteria are associated with restrained inflammatory reprogramming in human monocyte-derived dendritic cells. iScience. 2026;29(7):116583.
- Yong, CC.; et al. Human gut-associated Bifidobacterium species salvage exogenous indole, a uremic toxin precursor, to synthesize indole-3-lactic acid via tryptophan.Gut Microbes. 2024;16(1):2347728.
