We have so much information about our health at our fingertips these days, it can be hard to keep up. From at-home blood and sexual health tests to the sheer range of metrics measured by our fitness trackers, there are so many ways to keep an eye on what’s going on throughout your body.

But what all this tracking fails to acknowledge is the role our genetics play when it comes to our health. We know lifestyle-based interventions like exercise, nutrition and sleep can make a huge difference to the state of our health and overall longevity (aka, how long we live), but most of us know very little about our genetics and how they influence the impact these habits can have.

Thinking about your genetics can (understandably) be scary. Learning that you’re pre-disposed to a certain disease or health issue can be anxiety-inducing and difficult.

The good news, however, is that health is not black or white. There’s no single factor that decides your fate – it’s a combination of your lifestyle choices, environment and genetics. And knowing more about your genetics can also give you the tools you need to preempt any future issues.

The big question, then, is this: how big a role do our genetics actually play when it comes to our health and longevity, and how can we use this information to protect ourselves? Let’s explore.  

While our genetics can tell us some things about our lifespan (more on that later), you can’t predict how long someone will live based on their genetics alone.

“Recent years have seen incredible advances in our understanding of genetics and the human genome, but I don’t think we are at a point where we can predict someone’s lifespan from their genetic profile,” says Dr Adam Staten, an NHS GP and clinical director at One Day Tests.

“In fact, we are unlikely ever to predict this with any accuracy based on genes alone, as so many other things play a part in how long we live.”

There are lifespan insights to gain from your genetic profile though. According to Sebnem Unluisler, a genetic engineer at the London Regenerative Institute, the combination of genes we get from our parents contribute to around 20% of our lifespan variability (a measure of how much average life expectancy is left at the point of death).  

But the influence doesn’t stop there, because the expression of our genes – aka, the process by which the information in our genes is used to build the protein molecules which make up the human body – can be influenced by environmental factors.

This means certain genes can be switched ‘on’ or ‘off’ or undergo a change in structure due to external factors. – a process known as epigenetic modification. This can have a knock-on effect on the molecules they produce and how they impact health as a result.

However, says Unluisler, it’s important to think about the bigger picture when it comes to overall health. “Non-genetic factors significantly affect lifespan,” he says. “Lifestyle choices such as diet, exercise, smoking and socioeconomic status play crucial roles, as can access to healthcare, environmental conditions, and stress levels. Advancements in medical technology and healthcare practices can also extend lifespans by improving disease management and overall outcomes.” 

Our genetics can influence our lifespan in several ways, the first way being the link between specific gene mutations and life-limiting diseases.

“This is an area where our knowledge is growing all the time,” Dr Staten explains. “For a long time we have known that some specific gene mutations are associated with certain life-threatening diseases like the BRCA genes associated with breast and ovarian cancer, and our knowledge base of other genetic mutations that increase the risk of some cancers is growing all the time.”

DNA methylation (the term used to describe the process by which genes are switched ‘off’), has also been linked to issues including cancer, autoimmune disorders and neurological disorders.

However, DNA methylation isn’t necessarily a bad thing – it’s just a chemical process. Some genes tell a cell to self-destruct if it becomes damaged, which is key in the prevention of cancer. In this case, we want that gene to stay turned on, so if the opposite happens, we have a problem. However, DNA methylation has also been linked to increased longevity, because it can reverse harmful changes, too.

Different lifestyle changes and environmental exposures will also influence different genes, and the outcome depends on what gene has been turned off.

In this way, lifestyle factors like nutrition can influence your genetics and how they impact your health, as well as impact your health directly (for example, through the buildup of cholesterol in the bloodstream). Other lifestyle factors which can influence your epigenetics include stress, exercise, smoking, drinking and exposure to toxins or pollutants.

The world of genetics is incredibly complicated and developing rapidly, so you don’t need to worry too much about getting to grips with all the terminology.

The most important thing to note is that healthy lifestyle choices can have both a direct and indirect impact on your health due to your epigenetics – so eating well, getting enough sleep and moving regularly could be even more powerful than you realise.

In the future, experts also believe widescale genetic testing could help to personalise healthcare, so people who know they’re more at risk of a condition like, say, cardiovascular disease, could pay particular attention to their heart health and get tested more regularly.

“Understanding and modifying the factors which influence gene expression can mitigate genetic predispositions and promote healthier ageing,” Unluisler says.  

“Integrating genetic insights with lifestyle choices is essential for optimising longevity; while genetics contribute to lifespan, it’s crucial to consider the multifaceted interplay of genetic, environmental and lifestyle factors in determining overall longevity.”

Dr Staten agrees, but suggests the widespread use of genetics to inform healthcare could be a while off yet. “Researchers are beginning to identify genes that influence everything from our risk of developing certain skin problems to how we will respond to certain medications. In theory, this will allow healthcare to be tailored to everybody’s individual risk profile, but how, when or if this will translate into everyday medical practice is not clear.”

For now, however, it is possible to get your genes tested if you’re interested – there are plenty of at-home kits you can use to get a general idea of your DNA. People who are worried about their genetic pre-disposition to certain illnesses – for example, breast cancer – can also get their genes tested to see if they have any obvious mutations like BRCA1 and BRCA2.

For more information on these tests and what they can tell you, you can visit the NHS website. 

Images: Getty