Seeing What’s Inside

If you don’t see it, it’s not there, right?

And that’s how most people react when told of the extraordinary speed by which their body remakes itself.  I look at myself in the mirror now as I did four weeks ago.  My gut is approximately as big, my feet, my calves, my elbows.  Yeah, it’s the same me.

Still everything has changed.  Most of the changes are internal – remaking everything from the inside out.  We see our hair grow, our nails grow. But  we don’t see our brain grow – the new cells, the changed connections, the revamped DNA.

To visualize these changes occur, consider the python – not Monty Python, but your standard, everyday Amazonian python.

Double the Size of Your Heart

Pythons can grow pretty fast.  Until recently it was not clear just how fast.

A python can eat an animal as big as itself.  As reported in the New York Times, it grows internal organs in order to digest the latest meal.

How fast?  The heart, lung, spleen and other internal organs can double in size in a day.  Then they shrink, over a period of days to several weeks, back to their previous size.

Do they create new cells to accomplish this feat?  No.  They just make the existing ones bigger.

What kind of information performs this doubling size trick?  A group of three fatty acids.

One won’t succeed; nor two.  All three have to appear together.

Take the 3 fatty acids from a well fed python and give it to a starving one, and the starving python’s heart grows bigger.  Give the same fatty acids to a mouse?  It heart grows bigger, too  – in a healthy way, like that of a human athlete.

So here’s an example of cross-species information flow – change the fatty acids, and get a bigger, more athletic heart.

If  you get the information flow right, you can really change your body.

Human Rules Versus Python Rules

We don’t double the size of our hearts in a day, like pythons do.  But our pace of internal replacement is not slow; according to Professor Alma Cuervo at Einstein, we replace most of our hearts – minus cytoskeletal stuff like heart valves – in about three days.

How many  times have you felt or seen your heart replace itself in three days?

Other internal rearrangements are equally fast if physically unheralded.  The gut lining, faced with 100 trillion rapidly changing bacteria, sloughs itself off and completely replaces itself in a couple of days.  The skin on your face takes about two full weeks to completely reproduce.

Small molecules used for energy and metabolism, like glucose, are used, modified and repackaged within seconds to minutes.  Proteins, the information business end of most cells, don’t last; an Israeli study of the top 100 liver proteins found their chemical half lie – how long it takes for half of them to become completely replaced, not just repaired – ranged from 45 minutes to 22 hours.

Put it all together, and outside of structural stuff – like bones and teeth – and you are functionally remade in a few weeks.

A new view for many – but an old idea.

Change and Changing Changes

Rudolph Schoenheimer was one of the earliest cholesterol researchers who became interested in biochemical turnover with the advent of radioisotopes.  In 1923 Hevesi had noted that cells did not discriminate between radioactive isotopes – they used them indiscriminately.

So isotopes let you track metabolic changes over time.

Up till the 1920s people had felt cells were pretty much immortal.  Beyond using food for energy and building materials, their basic constituents stayed the same.

Schoenheimer, coming from Germany to Columbia to work with the great Harold Urey, demonstrated they were wrong.  He demonstrated cholesterol and other basic cell constituents turned over in periods of days and weeks.

Now we know such changes often take only hours.

Yet even today, people cannot wrap their minds around the velocity of life.  They can’t recognize that they are literally different from day to day – including memories. Partially this is because our brain, with its great gift for narrative, makes us feel that things are consistent far more than they are.

Which causes us to lose the advantages of seeing what really happens.

It’s rather like watching a movie.  Those bunch of stills get shown through a projector, and we see movement, three dimensional space, continuous activity.

Yet when it comes to our own bodies, we just see the  individual stills.

The Advantages of Speed

Possessing a mainly new body within four weeks is a very cool result.  It means that illness is not a failure of the machine but a breakdown of necessary replacement and remaking.

And just as when you’re remaking a new house from within, you get the chance to make it over.

Being healthy is about staying healthy.  If  we can get the replacement cycle to work – giving our body the right information and instructions  – we can avoid a lot of illnesses and find different means to get around the bottlenecks caused by the  ones we have.

If only we can see our bodies as they are – fast movers and rapid adapters.

So take a look at that new face you see each morning.  There’s lot you can do to remake and replace the stuff underneath the skin.

The pleasures that can bring should bring you a  smile.