Can the Environment Influence How We Age?
We often think about aging in terms of genetics, nutrition, exercise and lifestyle. But throughout life, our bodies are also continuously interacting with the environment around us.
The air we breathe, substances we encounter at work or at home, and exposure to certain metals, pesticides and other pollutants can all affect our biology.
Research increasingly suggests that these environmental influences may also interact with some of the processes involved in aging.
The environment becomes part of our biology
Scientists use the term exposome to describe the environmental exposures we experience throughout life and the biological effects they may produce.
The exposome is extremely broad. It can include air pollution, chemicals, occupational exposures, tobacco smoke and many other environmental influences.
Unlike our genetic sequence, these exposures can change considerably throughout life.
This makes the environment an important part of understanding why people of the same chronological age may have very different health trajectories.
How can pollution affect our cells?
Different pollutants act in different ways, but research has identified several biological pathways that appear repeatedly.
Air pollution, certain metals, pesticides and other environmental pollutants can increase the production of highly reactive molecules known as reactive oxygen species.
Our cells normally produce these molecules, and at controlled levels they perform useful biological functions.
Problems can develop when their production remains persistently higher than the body’s antioxidant and repair systems can manage. This state is called oxidative stress.
Over time, excessive oxidative stress can damage DNA, proteins and fats and interfere with normal cellular function.
What does this have to do with aging?
Many of the processes affected by persistent oxidative stress are also involved in aging.
These include mitochondrial dysfunction, DNA damage, chronic inflammation, cellular senescence and changes in the systems responsible for cellular repair and maintenance.
This creates a biologically plausible connection between long-term environmental exposure and aging.
Environmental pollutants may therefore contribute to biological conditions that make healthy aging more difficult.
But there is an important limit to what current research can tell us.
We cannot look at a person’s exposure history and reliably say that it has made that person biologically three, five or ten years older.
Can environmental exposure affect how our genes work?
Potentially, yes.
Environmental exposures and oxidative stress have been associated with epigenetic changes — modifications that influence how genes are regulated without changing the underlying DNA sequence.
Studies have found changes in DNA methylation and other forms of gene regulation following exposure to air pollution, heavy metals and other environmental factors.
These findings are important because they provide one possible mechanism through which environmental exposures could leave longer-lasting biological effects.
However, an epigenetic change is not automatically evidence that aging has accelerated. Some changes may reflect exposure, inflammation, adaptation or disease rather than aging itself.
What can we do with this information?
The most useful message is not that we should try to eliminate every environmental exposure. That is neither possible nor supported by evidence.
Instead, avoidable harmful exposures should be considered alongside other established determinants of long-term health.
Reducing tobacco smoke exposure, following occupational safety measures and reducing exposure to harmful pollutants where realistically possible are sensible measures for health protection.
At the same time, claims that a particular supplement, antioxidant or “detox” programme can reverse pollution-related biological aging go well beyond current evidence.
A broader view of healthy aging
Healthy aging is influenced by more than one pathway.
Genetics matter. So do blood pressure, metabolic health, physical activity, nutrition, smoking and other established health factors.
Environmental exposure adds another layer.
Research into the exposome may eventually help us understand more precisely how lifelong environmental influences interact with our individual biology.
For now, the strongest conclusion is more measured: our environment can influence biological processes involved in aging, but science cannot yet translate those exposures into a precise measure of how quickly an individual person is aging.
