What is epigenetic age and why does it matter?

Welcome to the fascinating world of epigenetics and its role in ageing.

This blog post delves into the epigenetic theory of ageing, a concept that has gained traction through numerous studies showing that our 'epigenetic age'— a measure of ageing based on DNA methylation patterns —can be influenced by factors such as diet, lifestyle, genetics, and disease.

We'll also explore the intriguing question: does our DNA change as we age?

Finally, we'll introduce you to different types of ageing clocks identified in scientific research. Get ready for a journey into the science of ageing, where we'll unravel the complex interactions between our genes, our choices, and the passing of time.

Sensory experiences trigger signals between neurons, prompting them to produce specialised proteins .

These proteins act as messengers, travelling to the gene library and attaching chemical tags that modulate gene expression.

Positive experiences, like rich learning environments, can foster the addition of beneficial tags, while negative influences, such as malnutrition or environmental toxins, can leave different marks. These tags can be temporary or permanent, altering how the brain interprets its genetic blueprint.

This phenomenon, known as epigenetic modification, highlights the profound impact of environment on gene expression.

1.2. What is the theory of epigenetic ageing

Ageing clocks have emerged as a powerful tool in predicting age-related health conditions .

These clocks, which measure our 'epigenetic age' based on patterns of DNA methylation, have been linked to a variety of factors including diet, exercise, and environmental exposures .

Research has shown that modifiable lifestyle factors can influence the global DNA methylation  landscape, thereby affecting our biological ageing process.

For instance, a balanced diet and regular exercise have been associated with a slower epigenetic age. On the flip side, chronic stress and poor diet can accelerate it.

These findings underscore the potential of lifestyle modifications in promoting healthier ageing.

1.3. Does our DNA change as we age?

While our core DNA sequence remains unaltered throughout life, the way our genes are expressed undergoes significant changes as we age.

This phenomenon, known as epigenetics, involves modifications to DNA methylation, histone acetylation, and other factors that influence gene accessibility . What this means is the following:

Imagine your DNA as a recipe book, with each gene a recipe for a specific protein. Epigenetics is like adding notes and highlights to those recipes.

These notes can tell your cells whether to cook a recipe (turn on a gene) or leave it closed (turn off a gene). As we age, these notes build up, affecting how cells use the recipes, which plays a role in why things change as we get older.

Studies have shown that age-related epigenetic changes accumulate in various tissues, which impact the functions of the cells and potentially contributes to ageing .

While these changes haven't been directly linked to changes in the DNA sequence itself, their influence on gene expression is important for understanding and potentially altering the ageing process . 

1.4. Types of ageing clocks

Ageing clocks analyse various aspects of your body, like DNA or blood tests, and predict your "biological age," which can differ from your chronological age. The first clock, created in 2011, used DNA methylation (chemical changes on your DNA) to estimate chronological age. Soon after, scientists built clocks using other sources like blood tests or facial photos. Today, dozens of ageing clocks exist.They don't just measure chronological age. Some, like PhenoAge, consider how healthy you are based on clinical markers. GrimAge looks at your risk of dying. Others, like DunedinPACE, track how quickly your body ages compared to others.

These " second-generation " clocks are more complex than the first, but both types are crucial for developing treatments that slow down ageing (geroprotective) or reverse damage (senolytic). Researchers are investing heavily in this field, but progress is slow. Ageing clocks offer a faster and cheaper way to test these treatments compared to waiting for people to live longer. Even some clocks are patented for wider use and validation.

2.1. Epigenetic programming and its importance and potential

Even though cells in your body have the same DNA, they behave differently because of tiny chemical tags and switches attached to their genes. These "notes" tell the genes which parts to use and which to ignore, essentially composing a unique song for each cell type.

But these melodies aren't written in stone. Early in life, they're more flexible, adapting to your experiences and surroundings ( stress, diet, maybe even pollution ). Over time, some notes become more permanent, potentially influencing your health later on.

Understanding these "notes" holds the key to personalised health. By decoding your unique epigenetic profile, we could create strategies to optimise your health, not just treat the symptoms but the cause.

2.2. How does epigenetic reprogramming work?

Epigenetic reprogramming has the remarkable ability to adapt the epigenome in response to environmental challenges, such as maternal stress. 

This adaptation can make the organism more or less adaptive depending on the future challenges presented.

This dynamic nature of the epigenome allows for a level of plasticity that can be both beneficial and detrimental to the organism. 

For instance, in response to stress, the epigenome can alter gene expression to increase resilience. However, these changes can also lead to maladaptive responses, potentially increasing susceptibility to diseases. 

2.4. Can ADHD be fixed through epigenetic changes?

Epigenetic changes, specifically DNA methylation, have been linked to ADHD symptom scores, suggesting a potential treatment avenue.

This implies that by modifying these methylation levels, we may be able to alleviate ADHD symptoms. This finding is significant as it provides a new perspective on ADHD treatment, moving away from a purely genetic view to a more dynamic, epigenetic approach.

This approach acknowledges that while genes may predispose an individual to ADHD, environmental factors and lifestyle changes can influence gene expression and potentially improve symptoms.