Researchers at Boston University have discovered that the blood of people aged 100 years and older contains a distinctive molecular profile that not only differs from that of typical older adults but also appears to predict exceptional longevity before a person reaches the age of 100. The findings were published in GeroScience.

The study was conducted as part of the New England Centenarian Study, one of the world's largest long-term investigations of exceptional longevity, led by Dr. Thomas Perls. The analysis included 213 participants: 70 centenarians and exceptionally long-lived individuals, their biological children, and an age-matched comparison group with no family history of exceptional longevity.

The researchers measured approximately 1,495 blood metabolites—small molecules produced during normal metabolic processes. This type of large-scale analysis, known as metabolomics, provides a comprehensive snapshot of the body's biochemical state.

One of the most striking features of the centenarians' blood was an unusually high level of bile acids. Produced by the liver, bile acids not only aid in fat digestion but also play important roles in regulating inflammation, immune function, and the gut microbiome. Unlike typical older adults, centenarians maintained both their primary bile acid pool (produced by the liver) and secondary bile acid pool (generated by gut bacteria).

A second distinguishing feature was the preservation of a more youthful steroid profile, including hormones and their precursors, such as molecules involved in the production of sex hormones. While these compounds typically decline sharply after the age of 70, they remained relatively well preserved in centenarians.

Using these findings, the researchers developed a machine learning model capable of estimating biological age based on an individual's metabolomic profile. According to the authors, these "metabolomic clocks" may be able to distinguish a biologically younger 80-year-old from a biologically older one and could eventually help identify individuals who are more likely to reach exceptional longevity.