If you want to live longer, you certainly want to be healthy and fit for as long as possible. The health span – i.e. the time we spend in old age without illness or disability – should ideally correspond to our lifespan. The “biological age” tells us whether our age goes hand in hand with good health. Biological age indicates how old our cells are and, in contrast to our chronological age, provides information on whether our cells are healthy and how quickly ageing processes take place in our body.
Our DNA: an indicator of biological age?
Biological age is determined by analyzing methylation patterns in the DNA. Depending on where in the DNA such methylations, i.e. changes, have taken place, conclusions can be drawn about various diseases, risks and our biological age. This is exactly what has been done with so-called “supercentenarians”, people who are over 110 years old. Surprisingly, it was found that their biological age was younger than their chronological age.
What factors influence biological age?
There are various factors that influence our biological age. In addition to genetics, which only accounts for 20%, epigenetics plays the most important role. The following lifestyle factors determine epigenetics and actively influence our biological age:
- Nutrition
- Sleep
- Sport & exercise
- Exposure to environmental toxins
- Psychosocial factors
DNA damage: how it sabotages our biological age
One sign that cells are getting older is that their DNA – i.e. their genetic code – becomes unstable. This genomic instability occurs when the DNA suffers damage. Our cells can normally repair this damage themselves, but there are many things in our everyday lives that make this process more difficult.
These include radiation, chemicals, pesticides and certain medications. Stress can also cause our cells to age faster and damage their DNA.
They all result in increased oxidative stress in the cells, causing them to age.
Telomere length: an important marker for our biological age
Telomeres have another important function with regard to our ageing process. Telomeres protect the ends of our chromosomes, the carriers of our DNA. You can think of them like the plastic protective caps on a shoelace. With each cell division, these protective caps become shorter. If they become so short that the DNA and the genome are damaged, the cell stops dividing and renewing itself. The cell ages and the risk of diseases such as cancer or Alzheimer’s increases.
The length of telomeres is therefore an important indicator of biological age, health and lifespan.
The epigenome – how it influences our biological age
Last but not least, the epigenome forms an entire system that is significantly involved in ageing. In contrast to the fixed genome, i.e. the genetic basis that every person inherits, the epigenome is a genetic reaction to our environment and our lifestyle. It controls which genes are activated or switched off as epigenetics. In response to factors such as exercise, diet, environmental toxins or oxidative stress, the epigenome decides whether, for example, longevity genes are activated. The older we get, the more susceptible the epigenome becomes to errors. As a result, we may, for example, lose muscle mass, the mitochondria produce less energy in the form of ATP, or so-called senescent cells accumulate.
Senescent cells: Harmful “zombies” that won’t go away
One major factor that can have a negative impact on our biological age is so-called senescent cells. Commonly referred to as “zombie cells”, they have long since lost their functionality for the body, but are still present in our body system without a task or purpose. As they can no longer divide, they have no relevant role in maintaining our bodily functions. Their main problem is that they do not die despite their inactivity. Even more worrying is that they release toxic substances in their “undead” state. These promote inflammation, contribute to the development of diseases and ultimately accelerate the ageing process of our body.
Conclusion
Genomic stability, the length of our telomeres and the epigenome ensure that our cells and DNA change and age in different ways. All these factors therefore also influence our biological age. If you would like to test your biological age, you can do so using our bioAge test and have your methylation profile and telomere length determined.
Sources:
- Brian H Chen et al. DNA methylation-based measures of biological age: meta-analysis predicting time to death. Aging (Albany NY). 2016 .
- Hans-Jürgen Gruber, Maria Donatella Semeraro, Wilfried Renner, Markus Herrmann. Telomeres and Age-Related Diseases – PMC. Biomedicines. 2021.
- Bérénice A Benayoun, Elizabeth A Pollina, Anne Brunet. Epigenetic regulation of ageing: linking environmental inputs to genomic stability. Nat Rev Mol Cell Biol. 2015.
- S M S Samarakoon, H M Chandola, B Ravishankar. Effect of dietary, social, and lifestyle determinants of accelerated aging and its common clinical presentation: A survey study. Ayu. 2011.
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