Growing old may be an inevitable part of our lives, but can we overcome the wrinkles and debilitating age-related diseases? What is the secret behind why some people spring into old age with energy and good health? According to science, some key answers could lie in your DNA.
New research published in Nature Communications has tackled this interesting genetic aspect of ageing. A team of scientists at the University of Edinburgh and the Max Planck Institute for Biology of Ageing embarked on a mission to scan the genomes of long-lived humans to find out what genes lie at the heart of their good health, even in old age.
Ageing, in the biological sense, is not described by the number of wrinkles. Rather, scientists make use of quantitative traits to measure ageing in humans. These include lifespan – the total number of years lived; healthspan – the number of morbidity-free, healthy years lived; and longevity – the capacity to survive until an exceptionally old age. And according to research estimates, around 10% of these traits have a genetic component.
In most efforts so far, obscure and noisy datasets have made it difficult to understand how these genes influence ageing.
Large sample sizes can provide meaningful, reliable data so the team pooled information from three public datasets using a genome-wide association study, GWAS. This technique enabled them to study the genome of over a million lifespans, with more than 60,000 extremely long-lived individuals.
They identified 10 regions in the genome which influenced ageing, the majority of which were also associated with cardiovascular disease – one of the leading causes of mortality.
Interestingly, the study showed that genes involved in metabolising blood iron correlated to all three measures of ageing – longevity, healthspan and lifespan. The team confirmed this strong link by a statistical approach called Mendalian randomisation.
“We are very excited by these findings as they strongly suggest that high levels of iron in the blood reduces our healthy years of life, and keeping these levels in check could prevent age-related damage”, said Dr Paul Timmers, from the University of Edinburgh.
This revelation shifted the researchers’ focus on blood iron levels as the robust data correlates to a lot of what is known.
This could bring us closer to helping older people live longer, healthier and higher-quality lives.
Blood iron levels, affected by diet, are an important part of our wellbeing. Ironis used to synthesise haem, a key component of haemoglobin – the oxygen carrier of your body. As haem synthesis declines with age, iron accumulates and this build-up decreases the ability of older patients to fight infections. These abnormal blood iron levels have also been associated with premature mortality and are often observed in neurodegenerative conditions like Alzheimer’s and Parkinson’s disease which are most common in patients aged 60 and older.
“We speculate that our findings on iron metabolism might also start to explain why very high levels of iron-rich red meat in the diet has been linked to age-related conditions such as heart disease”, Dr. Timmers added.
Such findings could be of great benefit to researchers trying to slow down ageing. Scientists hope to develop a drug that could mimic the influence of genetic variation on iron metabolism and overcome the morbidities associated with old age.
While experts urge caution about the interpretation of the results, the study is an exciting step in the right direction towards revolutionizing healthcare. With more research and sensitivity analyses, they could bring us closer to helping older people live longer, healthier and higher-quality lives. “Our ultimate aim is to discover how ageing is regulated and find ways to increase health during ageing. The ten regions of the genome we have discovered that are linked to lifespan, healthspan and longevity are all exciting candidates for further studies.” said Dr. Joris Deelen, from the Max Planck Institute for Biology of Ageing.
Written by Simran Kapoor and edited by Ailie McWhinnie.
Simran’s thoughts… Medical science and healthcare services have succeeded in increasing lifespans to an extent. But this can come at a cost, as a long lifespan are not necessarily synonymous with a high quality of life. Cardiovascular diseases, neurodegenerative diseases and frequent infections are just some of the illnesses that hit older age groups quite hard. Even during the COVID-19 pandemic, perhaps unsurprisingly, the virus has disproportionately impacted older people. It has shown us quite clearly that we have not yet succeeded in making the elderly less susceptible. What I find exciting about studies like this is that they can help scientists reach closer towards optimising healthcare for everyone and improve not just the length, but the quality of peoples’ lives.