In public discourse, the increasing lifespan in Western countries is often linked to longer life in good health. However, studying human aging in modern societies is complex because outcomes are shaped by numerous social, behavioral, and environmental factors, including medical advances, food security, poverty, alcohol use, and civil violence.
Penguins: A Clearer View of Physiological Aging
Penguins serve as an excellent model for understanding aging: they live 20–40 years, providing a reasonable timescale for research relevant to humans. Moreover, penguins have not undergone the same complex socio-economic changes as humans in Western countries over the past centuries.
"We wanted to investigate whether turning these penguins into nonchalant, well-fed, and well-cared-for individuals would alter their aging trajectory. Since this lifestyle already occurs in zoos, the setup was ideal," says Robin Cristofari from the University of Helsinki, first author of the new research paper published in Nature Communications.
The well-fed and sheltered environments for king penguin groups at Zoo Zurich (Switzerland) and Loro Parque (Tenerife/Spain) model conditions that closely resemble the modern human lifestyle. The results are unambiguous: living in a zoo accelerates the aging process in penguins.
"A 15-year-old penguin in the zoo has the body of a 20-year-old penguin in the wild. However, the interesting part is that zoo penguins also live longer, overall. They may be less physically fit, but with no natural predators or Antarctic storms to contend—with and with access to veterinary care—they can survive long past the age at which they would typically die in the Southern Ocean", explains a co-researcher Céline Le Bohec, from the French CNRS, who has studied King penguins in the wild for over two decades.
Researchers linked their findings to mechanisms involved in metabolism, as well as cellular growth, and maintenance. The key finding was that zoo conditions – including free access to food on a regular basis, limited physical activity, and the disruption of life rhythms – ultimately lead to accelerated aging.
How to Live Long and Stay Healthy?
Both penguins and humans live longer in modern environments with advanced health care, but this does not necessarily translate into improved health at older ages. Cristofari and his co‑researchers aim to understand what kind of lifestyle supports not only longer, but also healthier lives for penguins.
"We are currently conducting a study in which we induce penguins to eat less and exercise more. It is important to find a moderate lifestyle in a world of abundance - for us humans as well," concludes research curator Leyla Davis from Zoo Zurich.
The article titled "Lifestyle Change Accelerates Epigenetic Aging in King Penguins" was published in Nature Communications as a result of collaboration among the University of Helsinki, CNRS, the University of Hamburg, and Zoo Zurich.
