Older adults who took daily multivitamin supplements for two years aged more slowly at a cellular level, with an effect roughly equal to reducing their biological age by about four months. A large randomised clinical trial measured the biological age of nearly 1,000 healthy adults aged around 70 using blood samples to analyse age-related DNA changes known as methylation. Participants who took the multivitamin experienced slower ageing across all five DNA-based ageing measures compared with those taking a placebo.
Researchers measured biological age using 'epigenetic clocks' – tests that track age-related changes in DNA that reflect how fast the body is ageing biologically. The trial was led by researchers at Massachusetts General Brigham using data from the COSMOS trial, a large US study investigating the health effects of supplements. Participants were randomized to take a daily cocoa extract and multivitamin, daily cocoa extract and placebo, placebo and multivitamin, or placebos only.
Detailed findings from the multivitamin trial showed that the effect was strongest in people who were already ageing faster biologically than their actual age when the study began. Compared to the placebo-only group, the multivitamin group showed slowing in all five epigenetic clocks, with statistically significant slowing in two clocks predictive of mortality.
Scientists say the findings suggest multivitamins could be a simple, accessible way to support healthier ageing, although the benefits were modest. The researchers stressed that the study measured changes in DNA markers linked to ageing rather than actual lifespan or disease risk.
In a separate study, taking a daily Vitamin D supplement could help protect against dementia. Researchers found that people with higher levels of vitamin D in midlife had lower levels of a key Alzheimer's-related protein (tau) in the brain years later. The study found that higher Vitamin D levels were linked to lower tau protein, but there was no connection with amyloid beta.
The Vitamin D research followed 793 people with an average age of 39 who did not have dementia. Brain scans were performed an average of 16 years later to measure tau and amyloid beta proteins, both markers of Alzheimer's disease.
A limitation of the Vitamin D study is that Vitamin D levels were measured only once.
Following a specific dietary regimen can slow the brain's ageing process by more than two years. The research tracking brain ageing was published in the Journal of Neurology, Neurosurgery and Psychiatry and followed more than 1,600 adults for approximately 12 years.
Researchers in the USA have studied how daily intake of multivitamins affects ageing. Biological age, measured on a cellular level, can differ from chronological age.
The British Dietetic Association recommends that over-65s take a supplement of vitamin D of 10 micrograms per day to support bone and muscle health.
Further studies are needed to determine how improvements in biological ageing may explain reductions in clinical outcomes.
Key unknowns include the optimal dosage and formulation of multivitamins for slowing ageing, and whether it varies by individual factors. Additionally, the mechanisms by which vitamin D influences tau protein levels in the brain to potentially protect against dementia require further elucidation.
Unresolved questions also pertain to how long the benefits of multivitamin supplementation on biological ageing persist after stopping the supplements.