We all know people of our own age who look older – and younger – than we do. Each of us ages at our own pace and new research is uncovering how to measure the individual pace of ageing in young adults (Daniel Belsky and others, Proceedings of the National Academy of Sciences, June 2015). Luckily about 80 per cent of the factors that determine ageing are not genetic and we can exercise some control over them.
Humans can live to almost 120 years of age. Currently the world's oldest living person is a 116-year-old woman Susannah Mushatt Jones, who lives in Alabama. Average human lifespan is gradually lengthening, and the world population aged 80 and older will triple to about 400 million by 2050. From the age of 50, the burden of chronic ill-health conditions increases. The best way to reduce this disease burden is to increase the span of years lived free of disease and disability (healthspan) by delaying or reversing progression towards age-related diseases. In order to learn how to do this the ageing process must be studied.
Most studies of human ageing are carried out on older people, many of whom already have age-related diseases. The negative physiological changes that eventually progress to disease accumulate from early life, long before disease diagnosis, and interventions to slow or reverse this process must be made when people are still young. Ageing must therefore be particularly studied in the first half of lifespan before most diseases become established, but good methods to quantify the pace of ageing have not been available. This deficit is now being addressed by Belski and co.
In Belski’s study, 954 people born in 1972 or 1973 in Dunedin, New Zealand, were followed from age 26 to 38. Each was studied using a range of 18 factors known to be linked to ageing, including blood pressure, cardiovascular fitness, body-mass index, cholesterol, inflammation, blood fats, gum health, integrity of DNA and more. These scores were measured at 26, 32 and 38 years of age and were used to calculate a biological age for each person and also to determine the rate at which each person was ageing.
All participants in the study were the same chronological age, but Belski’s results showed that some were biologically older than their chronological age and ageing faster than others. Those who age faster also looked older, as assessed by random people looking at photographs. On the other hand, the good news is that some people were biologically younger than their chronological age and ageing more slowly. The ability to measure the pace of ageing will help to identify the causes of accelerated ageing and to evaluate therapies to slow down ageing.
Given the ageing factors used in this study, the evidence-based future extenders of youth will very likely involve measures such as maintaining a healthy weight, eating a healthy diet, reducing stress, taking regular exercise and boosting the immune system. Some of the world’s populations with the longest lifespans live along the Mediterranean coast and eat a diet rich in fruits, vegetables, olive oil, beans and fish, all washed down with a glass of wine. This diet is rich in antioxidants, which combat ageing triggered by stress and pollution and combat the inflammation associated with many chronic diseases.
How to live for longer
A new new study further bolsters the case for the Mediterranean diet (Marta Crous-Bou and others, British Medical Journal, December 2nd, 2014). This study showed that women who eat a Mediterranean diet have longer telomeres in their cells. Telomeres are bits of DNA located at the ends of chromosomes in our cells, and they shorten every time a cell divides. They shorten by half from infancy to adulthood and again by half among the elderly. Longer telomeres have been linked to longer life and shorter telomeres to shorter life.
Of course, the whole point of being alive in the first place is the opportunity this provides us to grow in wisdom and compassion while doing useful, interesting and enjoyable things. But I suppose we mostly pay far too little attention to this. As novelist Susan Ertz (1894-1985) said, “Millions long for immortality who don’t know what to do with themselves on a rainy Sunday.”
So, do useful and interesting things, eat a Mediterranean-like diet, take plenty of aerobic exercise, reduce your stress levels and look forward to living longer and healthier.
- William Reville is an emeritus professor of biochemistry at UCC, http://understandingscience.ucc.ie