There is only one certainty in life: everyone will die, from the poorest to the richest. Death is a certainty of life to humans, and we can’t defeat it… or can we?
Humans have been trying to avoid death for as long as we have been alive – from Qin Shihuang, First Emperor of China, to Bryan Johnson, the millionaire who claims he has found a way to cheat death. The latter has been a regular of recent news headlines, from using injections of his son’s blood to supposedly rejuvenate his body, to removing all of the plasma from his own blood in order to replace it with albumin. Most recently, he has appeared in a new documentary to motivate others to follow his example by engaging in diets and treatments to stop or reverse ageing.
With so much time and energy spent trying to develop technological equivalents of the fountain of youth, how close are we to arresting the march of time to cheat death or even significantly extend life?
Telomeres
Perhaps the most complicated category of life-extension technology aims to address telomeres – the DNA ‘caps’ that stop our chromosomes from separating or sticking to each other. Think of them as protectors, like the plastic tips at the ends of shoelaces.
Telomeres get shorter every time a cell divides, although telomerase stops this shortening for cells that divide a lot. This shortening is claimed to be associated with ageing; if so, logically, it is argued by some that if we could stop the from shortening or make telomerase active for all cells, we could have immortal cells. Preventing the shortening might not be impossible – we already have cells with effectively infinite telomeres: cancer cells. Many cancer cells can infinitely replicate, thanks to their telomeres.
However, despite what some theories claim, we don’t yet know the full effects of telomeres in ageing. Cellular ageing involves many factors, so it’s hard to know causality with certainty – we might find that we can arrest telomere shortening, which may not reduce cellular ageing. Even if we could make telomeres eternal, we might improve life expectancy, but we could still be just as far from the desired outcome of an immortal lifespan.
Stem cells
Another technology put forth as a potential cure for ageing involves harnessing stem cells, which are versatile cells capable of becoming other cell types, with the ability to repair and renew themselves. Stem cells are more present in the foetus/infant stages, as they are key to human development. They have a vast potential for research and improving the lives of humans, but the key words here are ‘improving’ and ‘extending’ life; they are not a miracle cure.
Imagine for a moment that we could use stem cells to regenerate all body parts (which, currently, we can’t). If you develop a liver problem, you could use stem cells to restore your liver to its youthful state. But what about the brain? Would we inject something into our brain that would slowly make all the old parts new again? The neuron activations and interactions in our lives form our memories and our personality; start to renew the cells, and you risk losing those features. Would you still be you if all your neurons were replaced with fresh new ones?
Fasting diets
Finally, life-extension claims often centre around intermittent fasting diets, which might involve eating and drinking in huge intervals, or periodically taking on board only water for 12 to 14 hours. This fasting forces the body to release specific substances claimed to help with ageing and health.
Is there any good science to back up those claims? Studies with mice showed some promise, but when it comes to humans, we have some problems. As one paper in the journal Frontiers in Nutrition explains:
Utilization of fasting diets to alter mood continue to have poorly understood effects and treatment options. Currently, it is not fully understood which fasting option provides the most beneficial effects on groups and even less on individuals nor are there consistent trials assessing the effects of fasting diets in a comparable manner.
Few short and long-term studies work within an isocaloric/isonitrogenous framework making it more difficult to assess the effectiveness of various fasting regimes. Similarly, baseline assessments and comparable populations are limited in many dietetic studies.
Even with the best results, researchers still urge caution and more research, especially as one study points out regarding mice studies:
Time-restricted feeding studies suggest this may be case, although caution is warranted in applying these results to humans. In mice, once-per-day CR feeding performed early in the dark cycle or early in the light cycle has equivalent effects on lifespan.
I suggest caution and avoiding fad diets or supposed miraculous solutions; we know that some people find benefit in fasting diets, but they aren’t a silver bullet for all health problems.
In conclusion
There are lots of theories around tech that could extend life, using diet, stem cells, and tech designed to target how our cells age. A lot of it is speculative, and where evidence exists, it’s in its infancy. Importantly, none of this would actually reverse ageing; at most, it could only slow ageing, and allow for longer lifespans.
