Have you ever wondered why some people remain healthy until the end of their lives, while others develop serious diseases in their youth? Stanford scientists have answered this question with a simple blood test. They were able to determine the biological age of individual organs.
This achievement not only shows which organ is aging rapidly but also predicts the risk of developing serious diseases, including Alzheimer’s.
Study Details
Scientists used plasma proteomics, a method that involves studying thousands of proteins in the blood. They analyzed blood samples from nearly 45,000 adults aged 40 to 70 from the UK Biobank. The scientists measured the levels of almost 3,000 proteins and, with the help of artificial intelligence, assessed the “biological age” of 11 organs (brain, heart, kidneys, lungs, and others).
Next, the team compared each person’s organ protein “signature” (i.e., the unique protein profile) with the average values for the corresponding age group. Based on this comparison, a new unit of measurement was created, called “organ age,” which shows how quickly or slowly the aging process is progressing in each organ.
Key Findings:
The biological age of the brain is particularly important: For example, people with an “older brain” are about 12 times more likely to be diagnosed with Alzheimer’s in the next decade. They also have an 82% higher risk of death within the next 15 years compared to their peers with a “younger brain.”
Organs age at different rates: This process is not simultaneous. One organ may maintain its “youth” while another ages more quickly.
The role of immunity is critical: If your immune system is “young,” it means you will live longer and cope better with age-related diseases.
Lifestyle affects organ age: Harmful habits, such as smoking, an unhealthy diet, and lack of exercise, accelerate the aging of organs.
Some medications can rejuvenate: It was found that ibuprofen, glucosamine, and vitamins may be associated with a younger biological age of the kidneys, brain, and pancreas.
These findings are truly promising, but the researchers note that there are also some limitations, including the need to include more diverse groups in the research and to collect long-term data to study the aging process over time.
The concept of biological age, on the one hand, helps us better understand the aging process, but on the other hand, it may prove to be depressing for society. To find out what the real potential of these tests is and what is hindering their implementation in clinical practice, Medscriptum spoke with one of the leading authors of the study, Hamilton Oh, who is known for his research in neuroscience, immunology, and the biology of aging.
Salome Chkheidze: Can you remember what your first reaction was when you saw that the biological age of the brain was so closely related to a long life?
Hamilton: At first, I had a hard time believing it because it was unexpected that only the biological age of the brain and the immune system had such a close connection with longevity. No similar connection was found for other organs. However, after a detailed analysis of the data, everything became logical. The brain and the immune system have an influence on the entire body, so it is likely that these two systems play a decisive role in controlling human lifespan.
Salome Chkheidze: Scientific research often considers aging as a slow and gradual process. Was there a moment during the research when you realized that the organs of the same person could be aging at different speeds?
Hamilton: Yes, of course. My supervisor and I had already seen in animal studies that different organs age at different rates. We wanted to determine to what extent this pattern applied to humans. When we saw that some organs were aging more slowly and some were aging faster, and that this also differed among individuals, it was a major discovery. This will certainly have a great impact on precision medicine.
Salome Chkheidze: Given these findings, do you think it is time for society to define “old age” by biological, rather than chronological, age?
Hamilton: This is a quite complex issue, and I think it is still too early to change this definition. While this field is developing in this direction, today, biological age tests are not yet reliable enough for clinical practice. Once the tests are refined, we may be able to focus on biological age instead of chronological age. For example, when prescribing treatment, doctors already use indicators such as cholesterol levels, which indirectly provide us with information about biological aging. On a cultural level, understanding biological age will help us to start caring for disease prevention from an earlier age.
Salome Chkheidze: Were there any unexpected cases in your research that raised new questions?
Hamilton: Yes, one interesting discovery was that some people had one organ that was significantly more “aged” than the others. This was unexpected for us. At first, we thought it might be a technical error, but we saw that this phenomenon was linked to the risk of disease, which indicates that it is real. Also, it is important to remember that the link between an organ’s biological age and disease risk differs for different organs and diseases, so we should approach this data with great caution.
Salome Chkheidze: Your data confirms that lifestyle is of great importance for the body’s resilience. How can your research deepen personalized interventions?
Hamilton: In the future, measuring an organ’s specific biological age will help us determine which patients will respond better to anti-aging medications. For example, if a specific drug reduces the age of an organ in some people but not in others, this will allow us to identify responders to the treatment and select individual therapy for them. With this method, patients will also be able to better understand the effectiveness of lifestyle changes or other therapies.
Salome Chkheidze: Given that these tests are not yet ready for routine clinical use, how would you explain their importance to Medscriptum’s readers?
Hamilton: This research is one of the first to show that it is possible to measure the biological age of each organ separately. It will probably take another five to ten years for these tests to become reliable enough for clinical use. However, even after that, doctors will only measure biological age if it helps them make specific medical recommendations.
For example, knowing that the biological age of your brain is higher than normal will only be useful if there is some effective method to correct it. If we tell a patient that their brain is “aged” but do not offer them ways to treat or prevent it, this information will be more harmful and stressful than useful. Therefore, the purpose of the tests is not only to identify the problem but also to simultaneously offer ways to solve it. Ultimately, patients will always have the right to choose whether or not to take such tests.
Salome Chkheidze: And finally, what is your team currently working on?
Hamilton: I plan to investigate how chronic psychological stress affects aging, and especially what role the connection between the brain and the immune system plays in systemic inflammation. My supervisor is analyzing cell-type-specific aging in organs to understand how different populations of cells, such as neurons and glial cells, age. These discoveries will deepen our knowledge of aging at the cellular level and are expected to be published in a few years.
See the full article on the following link: https://www.nature.com/articles/s41591-025-03798-1
