Story at a glance
- Life expectancy in the U.S. is about 79 years.
- Aging research suggests that humans can live healthy lives past the age of 100.
- The book “Lifespan” goes into the biology of aging and why some researchers are optimistic that we can live longer and healthier.
The conventional perspective on aging is that it is inevitable or “just the way things go.” We’ve been taught that aging is a natural part of life, that once you hit 30, it’s all downhill from there. Turns out, the research on aging suggests it doesn’t have to be. Researchers are asking what if the “natural” limit does not exist.
The average life expectancy in the U.S. is about 79 years. In the book “Lifespan,” researcher David Sinclair of Harvard Medical School with Matthew LaPlante of Utah State University go into detail about the work that suggests that humans may one day live well past the age of 100, even to the ripe old age of 150. It’s important to distinguish lifespan from “healthspan,” Sinclair writes in the book. Lifespan is the raw number of years a person is alive for, but healthspan is the number years of healthy life.
There’s no unified theory of aging, but what Sinclair thinks is the cause for aging is a loss of information in the epigenome. Epigenetics are the changes in what genes get expressed in response to what’s happening in and to the body like DNA damage or inflammation. In Sinclair’s early research, he focused on a class of proteins called sirtuins and their role in facilitating cell health. The sirtuins regulate which parts of the DNA are exposed and which are tightly wound up, making different genes available to be expressed.
Through many advances in the last few decades in Sinclair’s lab and others, researchers are getting closer and closer to understanding the aging process. There are different molecules like nicotinamide mononucleotide (NMN) that affect sirtuin activity and other parts of the epigenome. They’ve tested a lot of these in animal models like rats and mice and aging is looking more and more like something that is treatable.
Sinclair writes that one of the main issues preventing more progress is that aging is not defined as a disease. If it were, this would for one open up research and funding opportunities, but also could make treatments available to people. As it is now, there aren’t any aging treatments approved by Food and Drug Administration (FDA) on the market, although people may be prescribed metformin for diabetes and it may help. There are supplements that might be beneficial, but they aren’t regulated as thoroughly by the FDA for safety or efficacy. The results aren’t out yet on how they affect people, and that’s only a few studies in the last few years, so more research and trials are necessary.
For now, the only published studies are in animals, although anecdotal evidence may be enough to convince some people to start taking supplements. However, because those costs come out of pocket, there is also the issue of whether access to aging treatments could lead to richer people living longer, healthier lives but lower income people stuck in the medical system we have now that treats one disease at a time.
The authors stress in the book that everyone would benefit from treating aging like a disease. There are several advantages to approaching aging in this way. Because the end of life is currently usually a long and protracted affair, extending the healthspan of people would ease the burden on families caring for their aging relatives. “Spend a day in a nursing home like my wife does every few days,” writes Sinclair. “When you are done, I think you will agree that it would be negligent and cruel for you not to do what you can to combat your own age-related deterioration.” The authors also make the argument that extended healthspans could be good for economic productivity with more people working past the age of retirement.
So what’s happening globally? In 2018, the World Health Organization (WHO) added a code for old age as a reason for death in the 11th edition of the International Classification of Diseases, the system used by governments to report statistics to the WHO. This could be a big deal, opening doors to treat old age like a disease. But these codes won’t be actively used until 2022, and it could take several more years for individual governments to make the paradigm shift to make aging research and clinical trials a priority.
With accessible explanations of biological concepts and beautifully drawn infographics, “Lifespan” is a great read if you are interested in the science behind aging and why researchers are optimistic that we’ll be able to live healthy lives past 100 in the near future. Sinclair goes as far as to say that people may be able to meet their great-grandchildren and great-great-grandchildren, but he also talks about what the major barriers are to getting there research-wise and policy-wise. It’s a good read if you want to learn more about the research into potential ways to extend healthspans and lifespans or what Sinclair does in his own self-care regimen.