Scientists studying Brazil’s unusually high number of supercentenarians – people who live far beyond the age of 100 – have made a remarkable discovery about how their supercharged immune systems help keep them healthy into extreme old age.
Brazil is home to a disproportionate number of people who live past 110, making it a uniquely valuable setting for longevity research.
Now experts say these individuals appear to possess immune systems that have adapted specifically for longevity – renewing and recycling cells at a rate more typical of people decades younger.
This process helps prevent the build-up of damaged proteins and harmful mutations that drive age-related diseases such as heart disease, cancer and dementia.
Researchers from the University of São Paulo say Brazil’s long history of early colonisation, dating back to the 1500s, has created some of the richest genetic diversity in the world – a factor that may help explain why so many reach such advanced ages.
To investigate, the team analysed data from an ongoing study involving more than 140 centenarians and 20 supercentenarians drawn from diverse regions of South America’s largest country.
The cohort included Sister Inah, a Brazilian nun who was the world’s oldest living person until her death on 30 April 2025 at the age of 116.
It also included the world’s former oldest man, who died aged 112, as well as his successor, who is currently 113.
If there is a fountain of longevity out there, it’s probably somewhere in Brazil
But according to study lead Dr Mayana Zatz, professor of human and medical genetics, what makes this group so scientifically important isn’t just how long they live – but how well.
‘If there is a fountain of longevity out there,’ she said, ‘it’s probably somewhere in Brazil.’
Most of the supercentenarians studied remained mentally sharp and able to carry out daily tasks independently, despite having little or no access to modern healthcare.
On closer analysis, researchers found their immune systems – the body’s first line of defence against infection – behaved very differently from those of the general population.
Single-cell analysis revealed their immune cells maintained highly efficient protein-recycling and cellular ‘clean-up’ systems, similar to those seen in much younger people, helping the body dispose of potentially harmful mutations.
The team also discovered that CD4+ ‘helper’ T cells, which normally coordinate immune responses, behaved more like CD8+ killer cells – immune cells that directly attack infected or abnormal cells. This unusual pattern is rarely seen in younger populations.
During the Covid pandemic, the researchers found these immune systems adapted rapidly, producing neutralising antibodies and boosting immune-related proteins involved in early viral defence. Three supercentenarians in the study survived Covid-19 infections in 2020, before vaccines were available.
Writing in the journal Genomic Press, the researchers concluded that immune ageing in supercentenarians should not be seen as inevitable decline, but as a form of biological adaptation that preserves function.
The oldest living person in the world is now believed to be Ethel Caterham, from Surrey, who was born on August 21, 1909 and is 116 years old
The discovery also throws new light on previous research suggesting that people who live to extreme old age are not simply surviving illness for longer – but avoiding it altogether.
Large studies in Sweden have found centenarians develop far fewer serious diseases across their lifetime, accumulate health problems more slowly, and are significantly less likely to suffer major age-related conditions such as heart attacks, strokes and dementia.
In one analysis tracking more than 170,000 people for up to 40 years, those who went on to live past 100 had dramatically lower rates of cardiovascular disease even in their mid-80s, suggesting they were protected from illness long before reaching extreme old age.
Experts say the immune adaptations now identified in Brazilian supercentenarians may help explain this ‘super-ager’ effect – challenging the long-held belief that a longer life inevitably means more years spent in poor health.
Interestingly, the researchers noted that unlike other long-lived populations, Brazilian supercentenarians do not follow a specific diet such as the Mediterranean diet, which has been linked to heart health and longevity.
The team is now developing cellular models to identify protective biological mechanisms that may be unique to Brazil’s population – with the long-term aim of understanding how healthy ageing might be extended to the wider population.
