It is always pleasant to see more people writing seriously about aging and medicine, even if they omit what I see as some of the important viewpoints, or fail to end up advocating for massive funding of SENS research so as to make best speed towards an end to age-related frailty and disease. Certainly all too few people are willing to make that last leap at the moment. However, that there is more interest these days in treating aging as a medical condition and in the biological details of aging is a sign that the tide of public awareness is rising. In turn this should mean that it will become ever easier to raise funds in the years ahead - certainly I hope so, since I'll be doing my part to try to pull in grassroots funding for some of the more important lines of early-stage research.
At the grand scale this is all about persuasion, as is the case for all bootstrapped advocacy for a cause. You might recall a scientific study published a few years back on the tipping point of inevitability: where is the line that divides an opinion that remains forever fringe from an opinion that will become mainstream? The researchers suggested that the division is somewhere near 10% of the populace. I think we're getting there for important sections of the public when it comes to support for the medical control of aging in the same sense as the presently mainstream support for the medical control of cancer. Progress along this road accelerates rapidly as the tipping point nears, which is certainly a relief after the painfully slow early stages of talking people around to see common sense on medicine and aging, one individual at a time, and with frequent rejection. Certainly these past two years have seen things moving along at a much faster pace than the decade that preceded them.
If you had to guess how you were going to die, you could narrow it down pretty quickly. It takes only a handful of diseases to account for over half of the deaths of Americans each year. Only five in fact - heart disease, cancer, stroke, Alzheimer's disease, and diabetes. Though these disparate diseases affect different organ systems and develop as a result of different mechanisms, they all share a common underlying cause - the aging of the human body. It is aging that is the real killer here - aging kills more people on Earth than anything else. Maybe that's obvious, maybe it's not.
For a condition that kills so many, most of us don't have the slightest understanding of how aging works or why it happens. This series will ask the deceptively simple question, "Why do we age?" To tackle this, we will break this question into three distinct parts: "Why do we age?", "How do we age?", and "Is it possible to live longer?" The first will explore aging from the perspective of evolution, the second will delve into the actual mechanisms within our bodies that cause us to age, and the third will discuss scientific research into lifespan extension.
In general, the biological theories of aging can be split into two types: stochastic and programmed (stochastic just means random). Stochastic theories suggest that damage to our cellular components accumulates over time, leading to functional decline, and ultimately, death. On the other hand, programmed theories propose that aging arises from a set biological timetable, possibly the same one that regulates childhood growth and development.
Though stochastic and program theories are frequently presented as mutually exclusive, in reality they are connected, complementary, and deeply embedded in the interwoven, complex biological network that regulates all of life. To foster a holistic appreciation for the aging process, I will first layout the various theories of aging, and will then connect the pieces to construct a comprehensive map of aging.
Amazingly, the most widely studied method of lifespan extension requires no drugs, no supplements, no organ replacement. All that is required is reducing your caloric intake - just eat less. This practice, known as calorie restriction, has been observed to extend the lifespan of many species, from yeast to mice. Remarkably, initial findings have even shown that it can decrease the onset of age-related diseases in primates as well. To be clear, calorie restriction does not mean starving yourself, just reducing your caloric intake from a baseline level, typically by around 30%.
So why does calorie restriction work? From an evolutionary perspective, it is thought that in times of famine, organisms forgo reproducing, instead holding out for more prosperous times. As a result, it is advantageous to up-regulate genes involved in protection and repair and wait for better days to come. Essentially, we have specific genes that sense the availability of nutrients in the environment, and in times of scarcity, slow the process of aging, so that we may reproduce in more favorable conditions.