Taking a daily multivitamin may slow down biological ageing, a study has suggested.
Experts calculated that two years of daily vitamins cut biological ageing by about four months on average.
Biological ageing refers to how old the body is in terms of health and function rather than the number of years a person has lived.
Previous studies on the use of multivitamins and health have given mixed results, with one large study in 2024 showing no benefit when it comes to preventing early death and others showing they may have some effect.
In the latest trial, published in Nature Medicine, experts concluded that multivitamins may lead to “healthier, higher-quality” ageing.
Dr Howard Sesso, associate director of the division of preventive medicine at the Mass General Brigham Department of Medicine in the US, and lead author, said: “There is a lot of interest today in identifying ways to not just live longer, but to live better.
“It was exciting to see benefits of a multivitamin linked with markers of biological ageing.
“This study opens the door to learning more about accessible, safe interventions that contribute to healthier, higher-quality ageing.”
However, other experts cast doubt on the findings.
The study looked at biological ageing based on tiny changes to DNA.
Specific sites in DNA that regulate gene expression (known as DNA methylation) were examined as markers of ageing.
As the years go by, methylation patterns shift, forming the basis for what scientists term “epigenetic clocks”.
The blood samples of 958 randomly selected healthy people with an average chronological age of 70 were examined for DNA methylation.
Experts looked for changes in five epigenetic clocks at the start of the trial and at the end of the first and second years.
They found that, compared with people taking dummy drugs, those in the multivitamin group had slowing in all five epigenetic clocks.
The changes equated to about four months less biological ageing over the course of two years.
Further studies are now being carried out to see if the effects are long-lasting.
Dr Sesso said: “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.”
The study received a grant from Mars Edge, a segment of Mars, which included the donation of multivitamins for the study.
Dr Laura Sinclair, lecturer in healthcare and postdoctoral researcher at the University of Exeter, said epigenetic clocks “are powerful tools to measure biological ageing, but they are only one piece of the ageing puzzle”.
She said things such as DNA damage, changes in proteins, and problems in cellular communication also play a role in ageing.
“This study doesn’t recommend going out and buying supplements,” she said.
“If a person eats a nutritionally balanced diet, then many dietary supplements would probably be superfluous to their individual requirements.
“However, most adults in the UK are actually not eating a nutritionally balanced diet and so probably would benefit from a multivitamin-multimineral.
“Indeed, the UK Government suggests that UK adults should consider a vitamin D supplement in autumn and winter.
“Overall, this work provides evidence on the potential role of multivitamin supplementation in biological ageing, although the effects observed are limited.
“Within the broader context of diet and lifestyle, these results suggest that its impact would likely be complementary within wider strategies for promoting health and healthy ageing, rather than a standalone intervention with a decisive effect.”
Professor Luigi Fontana, from the University of Sydney and a director of the healthy longevity research, said: “This is a well-conducted trial, but the interpretation of the findings needs to be cautious.
“The study reports that a daily multivitamin slightly slowed two of five DNA-based ‘epigenetic clocks’ used as markers of biological ageing in older adults.
“However, the magnitude of the effect is extremely small, and the effect was not consistent across all the ageing measures tested…
“Overall, the findings are scientifically interesting, but they do not provide convincing evidence that taking a daily multivitamin meaningfully slows human ageing.”