Mass General Brigham trial links daily multivitamin to slower biological ageing on epigenetic clocks

Many millions of people swallow a multivitamin every day in the hope it will help them remain well as the years pass. Yet demonstrating a clear benefit has long proved elusive.

Scientists at Mass General Brigham have now reported evidence suggesting that this widely used supplement could affect biological ageing itself.

In a clinical trial of older adults, participants taking a daily multivitamin showed a slightly slower shift in certain “epigenetic clocks” - blood-based markers used to estimate the pace at which the body is ageing.

Across a two-year period, that gap amounted to roughly four months less biological ageing than was seen among those given a placebo.

The findings do not imply that vitamins halt ageing. Instead, they provide an uncommon signal that a straightforward nutritional supplement might gently steer internal ageing processes in a healthier direction.

The body’s internal ageing clock

The researchers used tools called epigenetic clocks - blood-based assessments that scientists employ to approximate how quickly the body is ageing.

These clocks work by analysing tiny chemical tags attached to DNA. Such tags can alter how genes behave as cells respond to time, stress and damage.

More recent versions of these clocks do more than estimate age alone. They are built to reflect risks associated with disease and survival.

For that reason, even subtle movements in these measures can draw interest - particularly when the intervention is as commonplace as a daily multivitamin.

Testing multivitamins in an ageing trial

This work was conducted within the broader Cocoa Supplement and Multivitamin Outcomes Study (COSMOS). For this component, the team tracked 958 healthy adults, whose average age was about 70.

Participants were randomly allocated to four groups, allowing investigators to disentangle the effects of a daily multivitamin from those of cocoa extract.

Over two years, volunteers provided blood samples during several check-ins. That approach enabled the researchers to follow changes in ageing markers over time rather than relying on a single moment in time.

Because assignment was random, the trial offered a much more rigorous test of the multivitamin than everyday supplement-taking habits.

A modest ageing slowdown

By year two, all five ageing clocks had shifted slightly in the same direction. Even so, only two changed enough to be clearly notable.

Those two clocks are tightly associated with the risk of dying from age-related disease, which made the observed shift more consequential.

When the full two-year span was considered, the multivitamin group showed about four months less biological ageing than the placebo group.

Still, participants did not become biologically younger, and the study does not state that the vitamin extends lifespan.

Who benefited the most

The largest apparent benefit was seen among participants whose biology already appeared older than their chronological age.

Within that group, the most pronounced shifts were again found on the same measures, suggesting the supplement’s effect was strongest where ageing seemed to be progressing most quickly.

In a smaller subset, lower nutrient markers were associated with faster ageing, pointing to the possibility that correcting subtle nutritional shortfalls could reduce cellular wear.

However, that explanation requires firmer evidence, and it is only one potential reason the benefit did not appear evenly across everyone.

Cocoa offered no ageing shift

By contrast, the cocoa extract arm did not slow any of the five ageing clocks in a persuasive way. This comparison was important because both supplements were evaluated within the same trial, against the same background variation.

One straightforward interpretation of this difference is that distinct interventions may influence different aspects of ageing, and these blood markers capture only part of the picture.

As a result, the multivitamin finding seems narrower - but also more specific - than a broad claim that supplements slow ageing overall.

Multivitamin benefits beyond ageing

Elsewhere in the COSMOS research programme, the multivitamin has shown hints of benefit. An earlier analysis reported improvements in overall thinking ability, memory and planning skills after three years of daily use.

However, the main COSMOS trial did not find reductions in total cancer or cardiovascular disease, even though lung cancer occurred less often in the supplement group.

Taken together, these mixed outcomes suggest there may be some benefits, but the overall evidence remains unclear.

Small changes, big questions

The shifts in the ageing clocks were small, and three of the five clocks did not show changes large enough to meet the same statistical threshold.

The participant group was also narrow. Most volunteers were white and all were older adults, so the results may not translate to younger people or to more diverse populations.

Another recent study reported similarly modest changes in ageing clocks with omega-3 supplements, implying that small shifts of this kind may be relatively common.

“There is a lot of interest today in identifying ways to not just live longer, but to live better,” said Dr. Howard Sesso, the study’s lead author.

Testing the multivitamin further

The team now aims to find out whether the slower clock readings persist once the trial is over. They also intend to examine whether these blood changes could help account for earlier indications of improved memory or reduced disease risk.

“A lot of people take a multivitamin without necessarily knowing any benefits from taking it, so the more we can learn about its potential health benefits, the better,” said Dr. Sesso.

That next phase is important because people do not take vitamins to improve a laboratory number - they take them to age well.

At this stage, the evidence indicates that a low-cost, familiar tablet does not stop ageing, but it may nudge two well-regarded blood measures in a slightly more youthful direction.

For now, this looks less like proof of a miracle and more like a careful lead that warrants further testing.