Epigenetic clocks are becoming a real breakthrough in health and longevity.
They are currently the best tools we have to assess our biological age. In other words, how old we really are.
They have considerable advantages over classic ways to “assess your global health”, like doing a blood test.
What are epigenetic clock tests?
Did you know you have two ages? Your chronological age and your biological age.
Your chronological age is based on your birth date. Chronologically, you might have been alive for 50 years. But, if you’ve been eating a lot of bad foods, do not exercise enough and you smoke, you may be the biological equivalent of a 62 year old, for example.
Epigenetic clocks are intended to determine your biological age. And this is important: your biological age is strongly correlated to your risk of dying (mortality risk) and your risk of getting aging-related diseases.
Epigenetic clocks versus classic screening
Determining your biological age is very interesting, because in general, doctors don’t have good tools to assess your global mortality and disease risk.
They have to rely on somewhat blunt tools, like measuring your weight, blood pressure, waist circumference, or by taking an MRI (which, for example, detects tumors when they are already too big) or by doing a blood test.
Blood tests are often done as medical health checkups, but unfortunately they’re not very refined tools to assess your health and mortality risk. For example, they look at cholesterol, inflammation (e.g., CRP), or kidney biomarkers, but many people with “normal cholesterol” levels, normal CRP levels, or normal kidney function still can be (very) unhealthy.
Blood tests can nonetheless be useful, but mainly to detect severe abnormalities. In that sense, a lot has to go wrong before your liver enzymes are increased, or CRP or kidney metabolite levels are too high (we explain more about blood testing here).
Epigenetic clocks could provide a much better overall picture of your health. They can provide an in-depth, global assessment of your mortality and disease risk.
How do epigenetic tests work?
Epigenetic clocks look at the methylation patterns on our DNA.
Methylation of the DNA is part of what we call the “epigenome”. The epigenome determines which genes are switched on or off.
One way to switch off genes is by adding small atom groups to the DNA (we call these small atom groups or molecules, methylgroups).
When a specific part of the DNA is “covered” with methyl groups, this part of the DNA becomes silent: the DNA, encoding for a protein, cannot be translated into protein.
Putting methyl groups on DNA is one way the epigenome regulates gene expression. This gene expression (and silencing) is very important.
All our cells have the same DNA but a liver cell is a liver cell because only liver cell genes are switched on (and not the heart genes, stomach cell genes, neuronal genes, and so on). A neuron is a neuron because the liver, heart and kidney genes are switched off by the epigenome.
Epigenetic dysregulation and aging
For example, housekeeping and repair genes that should be switched on are switched off, while cancer and inflammation-promoting genes are switched on.
The methylation patterns also change, not only because of aging, but because of many other factors.
If you smoke, some genes will be methylated more, and others less.
If you drink a lot, specific genes involved in alcohol detoxification will be epigenetically switched on.
If you have a lot of stress, stress-related genes will be demethylated so they can become more active.
The epigenome thus provides a sort of global blueprint about our general health and how old our body really is.
Epigenetic clocks look at hundreds of different spots in the DNA and see if there is a methyl group or not (more specifically, they look at whether a specific base pair, namely a cytosine, is methylated or not).
Mathematical or AI algorithms then correlate those methylation patterns with mortality and health.
Various epigenetic clocks already exist, such as the ones developed by Dr. Steve Horvath and his team, like the PhenoAge (R), GrimAge clock (R), and DNAmAge clock (R), while there are also many other clocks, like the Hannum clock (R).
Various companies are developing their own versions of clocks. But it’s important that these novel clocks are validated in scientific studies, preferably studies carried out by other scientists than the ones who developed the clock.
Epigenetic clocks are already fairly accurate, and will soon become even more so.
You can learn more about the epigenome and aging here.
Can I reverse my epigenetic age?
We talk more about epigenetically reversing aging here.