Your Organs May Age Differently

For much of medical history, age was a single number. However, recent research allows scientists to measure biological aging within the body, revealing that organs can age at different rates. This internal aging is driven by twelve distinct processes, including DNA damage and cellular inflammation. Blood tests can now estimate the age of individual organs, as certain proteins originate from specific organs. A study of nearly 5,700 adults found that almost one in five had a single organ significantly older than the rest, correlating with higher risks for specific illnesses such as heart failure or Alzheimer's disease.

Four new frontier drugs are being developed to target these aging processes. Rapamycin, a transplant drug, influences cell growth decisions. Semaglutide, used for diabetes, reduces inflammation. Rentosertib targets worn-out cells, and NMN supplements aim to boost cellular energy production. However, none of these drugs have yet demonstrated a slowing of aging in large clinical trials. Early results from a rentosertib trial showed a three-year decrease in predicted age among patients within four weeks, but this effect was not consistently seen across different types of aging clocks.

Experts caution that aging clocks, computer models that estimate age from blood samples, can be misleading. Some clocks are trained to recognize chronological age, while others are designed to predict illness risk. A review of 16 such clocks found that risk-based clocks respond reliably to genuine bodily changes, whereas age-based clocks show inconsistent results. "The clocks are misleading unless they are deployed in the context of a specific physiological condition," noted Deepak Kumar Saini of the Indian Institute of Science.

The most evidence-backed interventions for slowing biological aging are the oldest and most accessible. In healthy older adults, regular exercise, omega-3 and vitamin D supplements, a shingles vaccination, and daily multivitamins have each shown to move aging markers by months over two to three years. Some newer drugs, like rapamycin, carry significant risks, such as immune suppression, which can be particularly dangerous in regions with high infection rates like India.

Currently, the most practical application of this research is identifying which organ is aging fastest. Knowing this allows for closer monitoring of that specific organ using existing medical checks, regardless of whether a drug can slow the underlying aging process. Long-term clinical trials are underway to definitively answer whether slowing biological aging extends lifespan.