Growing old has more variation to it than you might think.

In the past it only happened one way, but the onset of modern medicine has forced us to spread in many different directions in order to keep humans alive.  The process has shed light on how the mechanics of aging actually work.

And what’s surprising is that aging is quite elastic.  And well conserved.  What causes a bacterial cell or fruit fly to deteriorate works basically the same way in humans and elephants.  And if you suppress the genes that express these different growth regulators you can extend lifespan by as much as 50%.

The process of aging comes down to two fundamental truths:

1. Aging is growth.  Growth within the body of practically any sort causes your cells to start accumulating and stop maintaining.  The lack of checks on a growth process causes the body to eventually become polluted and stop functioning.
2. Longevity feeds on destruction.  The other side of the coin is that when your body is put into extreme duress (like during exercise or fasting) it’s forced to reverse the growth process and the “flip” within your body causes it to recalibrate, and it regains its sense of when to store fat and when to burn it, when to secrete insulin and when to suppress it, etc.  This is what allows you to live a long time.

Cancer and obesity are also growth disorders.  And the process of growing old, getting cancer, and getting fat often go hand in hand.  It’s not a coincidence.  The hallmark of obese people are elevated levels of insulin, leptin, and other growth regulators which promote the accumulation of energy, and eventually waste products which prevent your body from functioning.  The hallmark of long-lived people are low levels of insulin, fat, and signaling pathways that promote cellular growth.

It’s why old people are flabby and flabby people die young.

Aging is a particular type of growth disorder that inhibits your body’s ability to regulate itself.  Diabetes, alzheimers, cancer, hypertension, fatty organs, and obesity are all underlying symptoms of the same regulatory mechanisms that have gone awry.

Death Begets Life

If your body isn’t storing energy then it’s looking to burn it.  In order to do this it literally begins to cannibalize itself.  If you remember back to your high school biology class there are parts of your cells called vacuoles and lysosomes who’s primary job is to allow your body to eat itself.  After you eat a meal and your body secretes insulin and activates the mTOR signaling pathway these parts of your cell get turned off so your body can store its food.

However, in the long run your body’s ability to destroy itself is absolutely vital to your well being.  It helps your body get rid of toxins, regenerate new cells, and get rid of old ones that are no longer working.  If it can’t do this your body begins to develop cellular ghettos, which act as breeding grounds for cancer and various metabolic diseases.

The economist Joseph Schumpeter made the observation that market economies operate on a mechanism he termed “Creative Destruction.”  It’s the constant churning of new methods of production, business models and capital that allow innovation and vitality to occur.  The analogy extends to your body.  It’s the distributed mini-deaths of organelles, cells and tissues that’s required for your body as a whole to thrive.

Your Body Is Never in Balance

Lots of health nuts equate the concept of balance with good health.  This is kind of true, but I think they get some important details wrong.  It connotes a vision of harmony that’s not really there.  In your body there really is no such thing as stasis.  Things are either trying to grow or getting destroyed, but never staying the same.  Good health is just making sure the switch is frequently getting switched in both directions.

If your body is dialed towards too much destruction you get atrophy, and the types of deformation that result from nutrient deficiencies and malnourishment.  You die because your organs have basically suffocated and can no longer function.  If your body is dialed towards too much growth you get the metabolic syndrome, and the types of deformation that result from unregulated feedback loop.  You die because your cells have lost the ability to communicate with themselves.

Why Grow Old in the First Place?

An interesting phenomenon is why different animals have different life spans in the first place. The process of growing old is remarkably unchanged throughout every single living organism.  The grim reaper gets high marks for consistency.  So why do some animals naturally live to be a few years old and others hundreds?

To understand why, it’s important to keep in mind why mother nature put you here in the first place.  To pass on your genes.  She really doesn’t care how long you live.  It’s plausible that natural selection doesn’t directly select for lifespan itself.  What it does select for is the ability for you to withstand harsh conditions long enough in order to pass on your genes.

Your body’s destructive state is also its survival state.  This is when it’s cannibalizing itself in order to stay alive.  When it’s in maintenance mode your body activates lots of genes which then promote longevity, since it’s unusually resistant to environmental shock.  Your growth state is your reproductive state.  In most animals growth spurts are associated with high levels of insulin and an increase in fertility.

But the biological assumption is that periods of feast are rare blips on the radar inbetween prolonged famine.  So growth naturally coincides with fertility, which naturally coincides with aging, because once you’ve passed on your genes you’re dead wood.

So it’s time to head on down the road………

References:

1).  Kenyon, Cynthia, et. al. “The Plasticity of Aging: Insights from Long-Lived Mutants”

URL: http://www.sciencedirect.com/science/article/pii/S0092867405001108

2).  Dazert, Eva, et. al. “mTOR signaling in disease”

URL: http://www.sciencedirect.com/science/article/pii/S0955067411001116

3). Zoncu, Roberto, et. al. “mTOR: from growth signal integration to cancer, diabetes and ageing”

URL: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3390257/

4). Cohen, Ehud, et. al. “The insulin paradox: aging, proteotoxicity and neurodegeneration”

URL: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2692886/