LECTURER: Thank you all for having me here today. Your professor asked me to come in and talk to you about the research we are doing these days on human longevity. It’s a fascinating topic, and one that I’ve been involved with as a scientist for over twenty years. Recently, we’ve been making a lot of headway in our research, so I’ll just, um, just share some of the key points with you.
Right. So, there’s a lot of popular information out there on longevity. All you have to do is run a simple Internet search, and you’ll find hundreds of thousands of articles by alternative medicine practitioners, independent researchers, or, you know, ordinary folks about how to live a long and healthy life. Some of this information can be helpful, but a lot of it is based on misperceptions. Today I’m going to discuss the scientific research, which goes a bit deeper into the topic, and which, quite honestly, I find more reliable.
We all know about the nature versus nurture debate, right? Well, this debate has been applied to human longevity as well. There’s been a sort of battle amongst scientists over whether genes or environment and behaviour ultimately determine a person’s lifespan. But, as you may have guessed, researchers are finding that it is neither one nor the other, but rather a combination of factors.
First, let’s talk about genetic factors. For a long while, researchers searched for what they called the “longevity gene.” Basically, the prevailing theory has been that longevity is predetermined by, by a person’s genetic makeup. Biologists had even identified a protein, SIRT3, as the possible key to slowing down the ageing process. What they found was that this protein helped aged stem cells cope with stress. When they infused the blood stem cells of mice containing this protein into ageing mice that didn’t test positive for SIRT3, there was evidence of a reversal in the age-related decline in the old stem cells’ function.
Sounds promising, right? But just months after the results of this study were released, another group of researchers published an article revealing several flaws in the study and casting doubt as to whether such a molecular fountain of youth truly exists. Their strongest critique was that the molecular-level response did not translate into longer lives for the mice. And, well, that’s quite an important point. So, it’s too early to jump to any conclusions yet about the implications of the discovery, but we can’t exactly write it off either. Certainly there seems to be a genetic component to longevity.
But most researchers agree that the causes of longevity are much more complex, and that even if there is a gene for longevity, that other factors...both environmental and behavioural...can weigh in just as much. Take, for example, an 80-year longitudinal study called “The Longevity Project” that was carried out by a team of social psychologists in the United States. It followed the lives of 1,500 people from the time they were kids in 1921, and tracked every possible environmental and behavioural factor to determine the character traits, habits, and mindsets that make some people live longer.
What was clear in the study was that personality characteristics and social relations from childhood are predictive of a person’s risk of dying decades later. In other words, there were correlations between certain behavioural or environmental factors and longevity. I’m sure you’re all very curious to hear the results, but I only have time to list a few of them. One is that it is the most prudent and persistent individuals, not the most cheerful and humorous ones, who survived the longest. Another one that may surprise you is that as adults, those who worked hardest and were most committed to their careers lived longer. Counter-intuitive, right? We often associate a relaxed, stress-free attitude with a longer, healthier life. But apparently that’s not, uh, not the case.
Anyway, I think you get the point that there aren’t simple answers to the root causes of longevity. Let me stop for now, and take your questions.