Your age isn’t just a number on your birthday cake—it’s also about how old your cells are, which scientists call your “biological age.”
While your chronological age counts the years you’ve been alive, your biological age reflects how old your cells feel, and this could be a better way to understand your health and risk of age-related diseases.
Recently, biological age tests that measure changes in your DNA have become popular.
These tests use blood or saliva samples to estimate how old your cells are by tracking changes known as the “epigenetic clock.”
As cells age, specific DNA changes become more frequent, allowing scientists to gauge your biological age.
However, it’s not that straightforward. The human body has about 200 different types of cells, and it’s unclear if the epigenetic clock moves at the same pace across all these cell types.
A new study by researchers from Harvard Medical School and Massachusetts General Hospital aimed to answer this question by looking at stem cells—special cells that can turn into different cell types and help repair tissues.
The study found that in tissues like skeletal muscle, blood, and the trachea, stem cells had a younger epigenetic age compared to the mature cells in those tissues. This suggests that stem cells might age more slowly in certain parts of the body.
However, this wasn’t the case for all tissues. For example, in the skin and intestines, stem cells were just as “old” as the mature cells.
The researchers also discovered that the age of a stem cell is connected to how quickly it divides and creates new cells to repair its tissue. Tissues like the skin and intestines, where cells divide rapidly, showed stem cells with an older epigenetic age.
These findings suggest that the biological age of tissues depends on the activity of their stem cells, which can change due to aging, injury, or disease. This research is important for improving the accuracy of biological age tests, making them more reliable in the future.
If you care about wellness, please read studies about how ultra-processed foods and red meat influence your longevity, and why seafood may boost healthy aging.
For more information about wellness, please see recent studies that olive oil may help you live longer, and vitamin D could help lower the risk of autoimmune diseases.
