Biological Age: A Key to Staying Healthy?

Anyone who wants to live longer will certainly also want to remain healthy and fit for as long as possible. Ideally, our healthspan – the period we spend free from illness or disability into old age – should match our lifespan. Whether ageing is accompanied by good health can be revealed by our “biological age”. Biological age indicates how old our cells are and, unlike chronological age, provides information about whether our cells are healthy and how quickly ageing processes are progressing in the body.

Table of contents

1. Our DNA: an indicator of biological age?
2. Which factors influence biological age?
3. DNA damage: how it undermines our biological age
4. Telomere length: an important marker of biological age
5. The epigenome – how it influences our biological age
6. Senescent cells: harmful “zombies” that refuse to disappear
7. Conclusion
8. Sources

Our DNA: an indicator of biological age?

Biological age is determined by analysing methylation patterns in DNA. Depending on where such methylation changes have occurred in the DNA, conclusions can be drawn about various diseases, risks and, ultimately, biological age. This is precisely what researchers have done in so-called “supercentenarians”, people who are more than 110 years old. Remarkably, their biological age was found to be younger than their chronological age.

Which factors influence biological age?

Various factors influence our biological age. In addition to genetics, which accounts for only 20%, epigenetics plays the most important role. The following lifestyle factors shape epigenetics and actively influence biological age:

• Diet
• Sleep
• Exercise & physical activity
• Exposure to environmental toxins
• Psychosocial factors

Key finding: Only around 20% of biological ageing is determined by our genes – by far the larger proportion is influenced by our own lifestyle.

DNA damage: how it undermines our biological age

One sign that cells are ageing is that their DNA – their genetic code – becomes unstable. This genomic instability develops when DNA is damaged. Our cells are normally able to repair this damage themselves, but many factors in everyday life can make this process more difficult.

These include radiation, chemicals, pesticides and certain medicines. Stress can also cause our cells to age more quickly and damage their DNA.

All of these factors result in increased oxidative stress within the cells, thereby accelerating cellular ageing.

Telomere length: an important marker of biological age

Telomeres perform another important function in the ageing process. Telomeres protect the ends of our chromosomes, which carry our DNA. They can be compared to the plastic protective caps at the ends of shoelaces. With every cell division, these protective caps become shorter. Once they become so short that the DNA and genome are at risk of damage, the cell stops dividing and renewing itself. The cell ages, and the risk of diseases such as cancer or Alzheimer’s disease increases.

Telomere length is therefore an important indicator of biological age, healthspan and lifespan.

The epigenome – how it influences our biological age

Finally, the epigenome forms an entire system that plays a major role in ageing. Unlike the fixed genome, the genetic foundation inherited by every person, the epigenome represents a genetic response to our environment and lifestyle. Through epigenetic mechanisms, it controls which genes are activated or switched off. In response to factors such as exercise, diet, environmental toxins or oxidative stress, the epigenome determines whether, for example, longevity genes are activated. The older we become, the more susceptible the epigenome becomes to errors. This can result in muscle loss, reduced ATP energy production by the mitochondria or the accumulation of so-called senescent cells.

You can read more about the twelve central mechanisms of cellular ageing – from epigenetics to telomere shortening – in our article The 12 causes of ageing.

Senescent cells: harmful “zombies” that refuse to disappear

One major factor that can negatively influence our biological age is the presence of senescent cells. Commonly known as “zombie cells”, they have long since lost their function in the body but nevertheless remain within our system without any useful role or purpose. Since they can no longer divide, they no longer contribute meaningfully to maintaining bodily functions. Their main problem is that, despite their inactivity, they do not die. Even more concerning is that, in their “undead” state, they release toxic substances. These promote inflammation, contribute to the development of disease and ultimately accelerate the ageing process of the body.

Good to know: The targeted removal of senescent cells is one of the most promising research approaches to counteracting ageing. Read more in our article Anti-ageing: promising developments.

Conclusion

Genomic stability, telomere length and the epigenome cause our cells and DNA to change and age in different ways. All of these factors therefore also influence biological age. Anyone wishing to test their biological age can do so with our bioAge Test and have their methylation profile and telomere length determined.

You can also read about the specific effects of lifestyle factors on biological age in our article What biological age reveals.

Sources

1. Chen BH, et al. DNA methylation-based measures of biological age: meta-analysis predicting time to death. Aging (Albany NY). 2016. pubmed.ncbi.nlm.nih.gov/27690265
2. Gruber HJ, Semeraro MD, Renner W, Herrmann M. Telomeres and Age-Related Diseases. Biomedicines. 2021. ncbi.nlm.nih.gov/pmc/articles/PMC8533433
3. Benayoun BA, Pollina EA, Brunet A. Epigenetic regulation of ageing: linking environmental inputs to genomic stability. Nat Rev Mol Cell Biol. 2015. pubmed.ncbi.nlm.nih.gov/26373265
4. Samarakoon SMS, Chandola HM, Ravishankar B. Effect of dietary, social, and lifestyle determinants of accelerated aging and its common clinical presentation: A survey study. Ayu. 2011. ncbi.nlm.nih.gov/pmc/articles/PMC3326874