What is aging?
At NEM we talk a lot about lifespan and healthspan and how we should proceed in order to live long and meaningful lives in good health – but what does it really mean to grow old?
In this article, we shortly explore our current understanding of the aging process. As humans age our bodily functions decline. The risk of acquiring anything from hearing loss and chronic diseases, e.g. type 2 diabetes and various forms of cancer to cardiovascular disease and cognitive impairment increases exponentially with a higher age. In fact, ageing is the primary risk factor for most neurodegenerative diseases, including Alzheimer disease and Parkinson disease.
Our bodies face cellular, hormonal and metabolic aging on a daily basis. The accumulated molecular and cellular damage resulting from the exposure to environmental toxins, pollution, UV-radiation, cigarette smoke and unhealthy foods are slowly leading to irreparable DNA damage. This damage is believed to be at the root cause of aging and leading researchers within the field of molecular genetics like Prof. David A. Sinclair are not only investigating the damage to our DNA and its correlation with aging but also the epigenetic changes that act as a driver for aging, in what Prof. Sinclair has termed the information theory of aging.
Your DNA codes for genes, i.e. the basic sequences of heredity that code for a certain target molecule, e.g. a protein. The sum of your genes is called the genome and remains largely static within an individual’s lifetime. On the other hand, the epigenome (a record of the chemical changes to your DNA and your histone proteins) is dynamic and can be altered by changes in environmental conditions. The epigenome is amongst other things responsible for regulating gene expression and tissue differentiation. It is the epigenome that tells your liver cell that it should be a liver cell and that a neuron should be a neuron – although they both contain the exact same DNA in their genome.
Changes to the epigenome can result in changes to the genome. Two main ways this happens is by DNA methylation and histone modification. Epigenetics researchers study methylation processes to determine your biological age, i.e. how old your body really is. Your chronological age might be 30 but at the same time due to increasing DNA damage and epigenetic changes your biological age might actually be 40. In our upcoming article we will discuss more about the factors that help to mitigate the DNA damage – and what you can do to rejuvenate your biological age.
David A. Sinclair, & Matthew D. LaPlante., (2019). Lifespan: Why We Age―and Why We Don’t Have To, New York, Atria Books
Hou Y, Dan X, Babbar M, Wei Y, Hasselbalch SG, Croteau DL, Bohr VA. (2019). Ageing as a risk factor for neurodegenerative disease, Nat Rev Neurol, available online: https://pubmed.ncbi.nlm.nih.gov/31501588/
The World Health Organization, (2018). Ageing and health, available online: https://www.who.int/news-room/fact-sheets/detail/ageing-and-health
Verywellhealth.com, (2020). Aging Types, Causes, and Prevention, available online: https://www.verywellhealth.com/what-is-aging-2224347
Veritasium, (2019). How to Slow Aging (and even reverse it), available online: https://www.youtube.com/watch?v=QRt7LjqJ45k&t=2s&ab_channel=Veritasium
Ted Talks, (2019). Why We Age and Why We Don’t Have To | David Sinclair | Talks at Google, available online at: https://www.youtube.com/watch?v=9nXop2lLDa4&ab_channel=TalksatGoogle
The Sinclair Lab, Research, available at: https://sinclair.hms.harvard.edu/research