Well. This is news to me.
Q: I've heard that every seven years, there's a complete turnover of body cells. If we keep getting these cellular 'makeovers,' why do we age?
A: Unfortunately, we don't get a 'cellular makeover' every seven years -- we just get seven years older. Different types of cells "turn over" at different rates. And some cells -- brain cells -- don't turn over at all.
I don't know when I first heard this notion, that the human body fully reproduces itself at the cellular level. When you think about it, it really isn't logical. But still, it's quite a romantic notion, anatomically speaking - the idea of being completely reborn every seven years.
Disappointed!!:( I loved the thought of periodic rebirth. This is worse than debunking Santa.
Posted by: BB | September 17, 2005 at 08:39 AM
Hmmm... I never labored under that impression. But I have always heard that women have a hormonal "shift" every 7 years... and doesn't your skin regenerate every 14? I should ask the 8 year old as he knows *everything*.
Posted by: Wende | September 18, 2005 at 11:53 AM
oh... that should have been "14 days". oops.
Posted by: Wende | September 18, 2005 at 11:54 AM
Cells do renew themselves and now it has been found that adult brain cells regenerate. We age because our cells have developed habits - just as we do and so when they reproduce, the habits are passed on. Why do you think Dolly died?
If we could change our 'thinking' or habit patterns or addictions of our cells, then we would not age, but sadly parts of our genetic coding has been switched off. We will have to learn to switch things on again.
Posted by: alys | January 05, 2006 at 01:37 PM
Don't understand the debunking theory. Skin sheds and reproduces. Cancer cells are "reproducing body cells in mutated form". So what's illogical about all body cells reproducing. Body wounds heal. Whats this if not a reproduction of tissue cells ?
Enlighten me please.
Posted by: graham | August 02, 2007 at 05:45 AM
Yes, they do.
And I can say this with conviction because I have personally experienced the change, twice.
You can laugh all you want, "debunk" me.. whatever.
But I didn't hear about this cell change idea until after I experienced it, years later...and realized it was every 7 years incidentally these changes were happening to me. Coincidence?
To what extent, why or how...I am no scientist. Just another human if you will.
As those that say they "saw the light"... you can believe or not. But you can be damned sure when you as your own person say you have experienced something, no-one can debunk you. They are not you.
Posted by: Christene | August 04, 2007 at 02:02 PM
Neurons - "brain cells" - aren't replaced. That means you don't get a new brain. Unfortunately.
Also, it's not that you spontaneously regenerate yourself every 7 years. You don't go into a cocoon and come out all brand new all of a sudden. It's a constant process and cells regenerate at drastically different rates. You'd never notice it.
So, any change you notice is purely psychological.
Posted by: A Scientist | November 02, 2007 at 03:42 PM
As I understand it, the idea wasn't about cells, it was about atoms.
With the rate of turnover of cells and the constant repair of cells, the longest atoms were supposed to stay in your body was 7 years.
Many atoms, such as those in your lungs are lost every breath, so this “7 years” was a maximum. Also, it would have been a statistical calculation.
You loose x carbons and y hydrogens in n years, therefore your body has used enough carbon and hydrogen to replace itself.
The calculation would have involved all the elements, probably as an average uptake and excretion thing.
If I find a reference for it i will let you know :-)
Posted by: loqk | March 28, 2008 at 04:36 AM
You can go to http://wiki.answers.com/Q/Does_the_human_body_regenerate_every_7_years
for some interesting information on this concept and references for further study
Posted by: JimP | April 11, 2009 at 08:21 AM
It's not at all illogical, cells renew on a daily basis, the epigenome can change in the transcription stage causing mutations which is what causes diseases.
Our body is constantly adapting to it's environment it would make a lot more sense if it did completely regenerate, it would explain aging as dna and protein production becomes weaker each time we re generate, it's like a photocopier it'll eventally break after so many copies have been made.
Posted by: Cinders | April 26, 2010 at 08:30 AM
The photocopier analogy is apt but not, I believe, in quite the way it's been suggested.
I think it's probably more accurate to hypothesise that each copy of the original document will be progressively flawed until it will eventually become illegible.
Posted by: J C | September 22, 2010 at 09:54 AM
This scientific and detailed article (see link below) is useful, and suggests that current evidence can back up, or at least explain the 7-year theory. It seems most of our atoms "turn over" in approximately 7-10 years, while some do take less or more time.
http://www.madsci.org/posts/archives/2005-08/1123273958.Bc.r.html
Posted by: Toria Burrell | September 26, 2010 at 10:25 PM