What Is Ageing? A Primer to Understand the Hallmarks of How We Grow Older.
- Alastair Hunt
- 3 days ago
- 7 min read
Updated: 11 minutes ago
Why do we age? It’s a question that has fascinated scientists and philosophers alike for centuries. Now, thanks to decades of research, we have a clearer understanding of the biological changes that take place as we grow older.
These changes, known as the hallmarks of ageing, offer insight into why our bodies slow down over time - and more importantly, how we might stay healthier for longer.
As ever, please talk to your doctor or medical practitioner most familiar with your medical history before implementing any changes in diet, exercise or lifestyle, especially if you are under treatment. Links to all studies at bottom of page.
What Ageing Really Means
Biological ageing isn’t just about grey hair or wrinkles. It refers to the gradual loss of function across all systems of the body - from how cells repair damage, to how organs communicate and recover. While everyone ages chronologically (one birthday at a time), biological ageing can vary widely between individuals. That’s why some people remain vibrant well into their 90s, while others experience age-related diseases much earlier.
In 2013, scientists proposed that there were nine key “hallmarks” of ageing. These are biological processes that:
Appear more prominently as we age
Speed up ageing when made worse
Can potentially be slowed or even reversed with specific treatments
As research progressed, this list - in 2023 - expanded to 12 hallmarks, offering a more complete picture of what really drives ageing.
The 12 Hallmarks of Ageing
1. Genomic Instability
Our DNA is like the instruction manual for building and maintaining every part of our body. Over time, it's battered by environmental toxins (like UV rays and pollution), lifestyle factors (such as smoking) and natural wear and tear. Normally, our cells are great at fixing this damage, but as we age, these repair systems become less efficient. This leads to mistakes in the DNA - known as mutations - which can impair cell function or lead to diseases like cancer.
Supporting your DNA involves minimising exposure to harmful chemicals, staying physically active, and eating a diet rich in polyphenol antioxidants (found in berries, leafy greens, and nuts), which help neutralise the free radicals that can damage DNA.
2. Telomere Attrition
Telomeres are protective caps at the ends of our chromosomes. Think of them like the plastic tips on shoelaces that stop them fraying. Every time a cell divides, telomeres get a little shorter. Eventually, they become too short to protect the chromosome, and the cell stops dividing - a process linked to ageing. Telomere shortening has been linked to stress, smoking and obesity.
On the flip side, meditation, regular exercise, and a diet high in fibre and low in processed foods may help preserve telomere length. Some research even suggests that improved sleep and social support could play a role.
3. Epigenetic Alterations
Genes can be switched on or off depending on our environment and behaviours, a process governed by epigenetic markers. With age, this fine-tuned system becomes erratic, leading to inappropriate gene expression. These changes can affect everything from inflammation to metabolism. Fascinatingly, some lifestyle changes appear to influence epigenetics, altering how genes are expressed without changing the DNA itself. Learn more about epigenetic clocks and testing.
Studies show that a balanced diet, regular exercise, managing stress and avoiding exposure to toxins may all help maintain healthier epigenetic patterns. Some trials even suggest that specific diets, like those rich in plant-based nutrients and polyphenols, could "rejuvenate" certain epigenetic markers.
4. Loss of Proteostasis
Proteins are essential for almost every cellular function. As we age, the systems that build, fold, and recycle these proteins become less efficient, leading to a build-up of damaged or misfolded proteins. This is implicated in several neurodegenerative diseases, such as Alzheimer's and Parkinson's. Proteostasis is the body’s process of making, folding and clearing out proteins to keep cells healthy and functioning properly.
Lifestyle strategies that may help preserve proteostasis include regular physical activity, intermittent fasting (which may trigger cellular clean-up), and potentially eating more polyphenol-rich foods like green tea and dark chocolate, which support cellular health.
5. Disabled Macroautophagy
Autophagy is the body's way of clearing out damaged components inside cells - like taking out the cellular rubbish. With age, autophagy slows down, leading to a build-up of cellular clutter. This contributes to a range of age-related diseases.
Interventions like fasting (especially intermittent fasting), exercise, and compounds like spermidine (found in some cheeses, soy products, and wheat germ) have been shown in studies to promote autophagy. Adequate sleep is also important, as autophagy appears to be linked to circadian rhythms.
6. Deregulated Nutrient-Sensing
Cells are constantly monitoring energy levels through pathways that sense nutrients like glucose and amino acids. With age, this system becomes unbalanced. Too much nutrient signalling, especially from overconsumption of calories, can push cells into growth mode when they should be in maintenance or repair.
Caloric restriction, time-restricted eating, and diets like the Mediterranean diet help restore this balance. These dietary patterns can mimic fasting signals that promote cellular repair over growth. Prof. Luigi Fontana's book, The Path to Longevity, is a fantastic resource to learn more.
7. Mitochondrial Dysfunction
Mitochondria are the power plants of cells, generating the energy we need to live. As they age, they become less efficient and produce more by-products like reactive oxygen species, which damage cells.
Supporting mitochondrial function can involve aerobic exercise (which boosts mitochondrial health), getting enough sleep, and eating foods rich in coenzyme Q10 (like oily fish), B vitamins and certain amino acids.
8. Cellular Senescence
When cells become damaged beyond repair, they enter a state called senescence - where they stop dividing but don’t die. These senescent cells release inflammatory signals that damage surrounding tissue. Over time, they accumulate and contribute to ageing and disease.
Certain flavonoids, like quercetin (found in apples, onions and green tea), are being studied for their "senolytic" properties - meaning they may help kill and clear out these 'zombie' cells. Regular movement and strength training may also reduce senescent cell build-up by improving tissue turnover.
Learn how skin aging reflects our own, internal aging.
9. Stem Cell Exhaustion
Stem cells are our body’s repair system, but their numbers and functionality decline with age. This slows healing and tissue regeneration.
Supporting stem cells may include avoiding toxins like tobacco and excessive alcohol, maintaining a nutrient-dense diet, and engaging in regular exercise. Some studies suggest that strategies like cold exposure or fasting could stimulate stem cell activity, though more research is needed.
10. Altered Intercellular Communication
Our cells communicate via chemical signals. As we age, this system becomes distorted, leading to chronic inflammation and miscommunication between tissues. This affects everything from immune response to hormonal balance.
Reducing systemic inflammation through diet (e.g., omega-3s from fish, nuts and seeds), stress management techniques, and social connection can help preserve healthy communication between cells.
11. Chronic Inflammation
Low-level inflammation, known as "inflammaging", gradually damages tissues and underpins many chronic diseases. It is often fuelled by poor diet, stress, pollution and infections.
Anti-inflammatory foods like leafy greens, berries and turmeric, along with regular movement and enough restorative sleep, are helpful. Meditation, yoga, and even spending time in nature have also been shown to lower inflammation markers.
Learn more about inflammaging here.
12. Dysbiosis
Our gut microbiome - the trillions of bacteria living in our digestive tract - plays a key role in immunity, mood, and metabolism. Ageing tends to reduce the diversity of this ecosystem, a condition called dysbiosis. This can increase inflammation and vulnerability to disease.
Eating a variety of fibre-rich plant foods, fermented products like yoghurt and kefir, and limiting processed foods all support a healthy microbiome. Some people may also benefit from targeted probiotic supplements.
Final Thoughts
Ageing is a universal experience, as many of us can see from our wrinkles, but the science behind it is rapidly evolving. While we can’t stop the clock, we can make choices that influence how we age. The 12 hallmarks of ageing offer a framework for understanding the biological shifts that shape our later years - and highlight where interventions might help us live not just longer, but better.
Ultimately 'aging well' is about us as individuals, taking responsibility for our own health and self-care.
Supporting your body through balanced nutrition, physical activity, stress reduction, quality sleep and meaningful social connection (these are known as the Pillars of Health) are some of the most powerful longevity tools we have. As always, it's about progress, not perfection, and even small changes can make a meaningful difference over time.
As always, the best health strategy is one you can stick with - one that fits your personal lifestyle profile. For most people, improving health is about finding motivation and prioritising self-care - with an ultimate goal of taking action. If you want to take effective and targeted steps that fit into your unique lifestyle and circumstances, The Whole Health Practice is here to help.
Whether your interest is healthspan and longevity, to beat chronic illness or to enhance your mental health and well-being, our consultations and programs deliver results that are tailored to your needs.
Our foundational Whole Health Consult identifies and prioritises the key factors - known and unknown - that affect health and wellbeing. It provides targeted recommendations tailored to you, the individual, and your unique lifestyle.
Stay Healthy,
Alastair
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Related Studies
López-Otín C, Blasco MA, Partridge L, Serrano M, Kroemer G. Hallmarks of aging: An expanding universe. Cell. 2023 Jan 19;186(2):243-278. doi: 10.1016/j.cell.2022.11.001. Epub 2023 Jan 3. PMID: 36599349.
Liu Y, Fang M, Tu X, Mo X, Zhang L, Yang B, Wang F, Kim YB, Huang C, Chen L, Fan S. Dietary Polyphenols as Anti-Aging Agents: Targeting the Hallmarks of Aging. Nutrients. 2024 Sep 29;16(19):3305. doi: 10.3390/nu16193305. PMID: 39408272; PMCID: PMC11478989.
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