The telomere revolution
The tiny telomeres on our DNA may hold the key to living longer, ageing better and staying healthier. But can we improve our telomere health?
Health Agenda magazine
Found deep in the very centre of our cells, telomeres could be the key to living longer and staying healthier – and may also hold clues to cancer, heart disease and many other diseases.
Protecting our DNA
Within human cells, chromosomes containing our unique genetic code are capped by protective tips – telomeres – which stop critical DNA strands being chopped off each time those cells divide. Chromosomes have a thread-like structure, with molecules of DNA as their core component. DNA contains the genetic instructions that drive the growth, development, functioning and reproduction of all living organisms, including people.
“Telomeres are the DNA version of the canary in the coalmine; they sense when your cell is not happy and can be a signal for various problems,” says molecular biologist Dr Hilda Pickett. “The evidence suggests that short telomeres can mean you’re more likely to have various health impacts like cardiovascular disease or that you may respond differently to drug treatments like chemotherapy.”
Dr Pickett heads the Telomere Length Regulation Unit, within the Children’s Medical Research Institute at Sydney’s Westmead Hospital, involved in exploring different aspects of the structure and functions of telomeres.
Our telomeres are longest at conception and steadily decrease over our lifespan – but we don’t yet know whether they actually cause ageing or this shortening is just a sign of ageing.
Dr Pickett says research into the role and influence of these telomeres is heating up globally, with intriguing new discoveries unlocking information about our potential to influence human health and longevity at a cellular level.
The long and the short of telomeres
Hobart-born scientist Elizabeth Blackburn shot to fame in 2009 when, with 2 colleagues, she was awarded the Nobel Prize in Physiology or Medicine for the discovery of telomerase, the enzyme that replenishes telomeres.
Blackburn has since co-written a book called The Telomere Effect, which documents how the process of telomere shortening can stop our cells replicating so that they age and die, and how we can slow down or even reverse that process.
She says we all have a ‘health span’ – the number of years we’ll remain active and disease-free. Our telomeres shorten as we age, influencing our shift from that health span into the disease span. But research now shows that managing chronic stress, exercising regularly, eating a healthy diet and sleeping well can all have a measurable effect on our bodies at the cellular level.
Telomeres and disease
Within our bodies, cells divide in a process known as mitosis. This natural division allows the human body to generate new cells – a critical step in sustaining itself – and continues throughout our lifetimes. Each time normal human cells divide, their telomeres shorten. Individual cells typically stop growing and die when the telomeres become too short, after about 50 cell divisions.
“But cancer cells are basically immortal cells: they just keep dividing over and over again; they’ve lost all their controls of cell proliferation,” Dr Pickett says. “To do that, they either have to maintain their telomeres or must have super-long telomeres to start with.”
She says about 85% of cancerous cells activate telomerase, an enzyme that lengthens a cell’s telomeres, while a further 15% of cancers use a DNA repair mechanism called alternative lengthening of telomeres, or ALT.
“Because so many cancers use one of these mechanisms, understanding how they work is very promising for anti-cancer therapy,” Dr Pickett says, adding that there are already trials underway for a leukaemia drug that taps into this research.
Change your future
Dr Caroline Bull, a CSIRO research scientist who specialises in nutritional genomics, says understanding telomeres could help us improve our health span. This involves increasing the healthy years of our life and compressing disease into a very short timeframe rather than having people live with chronic disease for decades.
“Health problems associated with poor DNA health include Alzheimer’s disease, numerous cancers, diabetes, reproductive failure and cardiovascular disease,” she says.
1. Focus on nutrition: “Nutritional factors play a really important role in maintaining optimal DNA replication,” she says. Her research encompasses the effects of diet on DNA health – in particular, the role of folate and vitamin B12. Folate is found naturally in avocado, leafy green vegetables, beetroot, asparagus and liver, and B12 is in foods including meat, poultry, seafood, milk, cheese and eggs.
In addition to folate and vitamin B12, plant foods in general, fibre and omega-3 fatty acids are recommended for sound telomere health; telomere shortening has been associated with an increased intake of red and/or processed meat, soft drinks, sodium and white bread.
2. Minimise stress: “We know that good-quality sleep and regular exercise are protective against the effects of stress,” Dr Bull says. “We also know that chronically stressed people tend to have shorter telomeres and lower amounts of the enzyme that protects them.”
“Chronic psychological stress can damage your telomeres. While we may not be able to stop people’s exposure to stress, there are things we can do to mitigate its effects, such as exercise or meditation and relaxation techniques.”
3. Exercise regularly: Dr Josh Denham, who lectures in clinical exercise physiology at the University of New England in Armidale, has been immersed in the link between exercise and telomere health for some years now. In 2011 he compared the DNA of endurance athletes who ran about 70–100km a week with that of a non-exercising control group. He found the telomeres of endurance athletes were about 11% longer – equating to an estimated 16 years of biological longevity.
You don’t have to become a marathon runner to improve your telomere health through exercise; studies of people who have followed exercise programs over a 6-month period have shown telomerase activity increasing over that time, Dr Denham says.
“We’ve known for years that moderate exercise can prevent many age-related diseases,” he says. “My recommendation for improving your cellular health is truly nothing new: exercise regularly. Pick an activity that you enjoy and that you’re going to adhere to.”
He says at least 30 minutes a day of moderate-intensity exercise is likely to be sufficient to boost telomere health.
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