I don't know any specific place to point to, but I have heard this from scientists that I know.
None the less the point I was trying to make was more that the body is in flux not simply a static thing.
I am well aware of that, but simply claiming it's an urban myth is not the same as proving it's wrong. I have provided the links I could find, take that for what you want.
It doesn't take a hundred or even 50 years why do you think the body fall apart over time. If the body was static we wouldn't die let a lone grow up to die.
It is a fact that the human body is in flux and not stable it is also a fact that your cells most of them die out pretty fast which is why we have to eat and drink. And that is what matters. The you today isn't the same you as 7 years ago.
http://www.madsci.org/posts/archives/2005-08/1123273958.Bc.r...
The cells in the body do turn over, but not uniformly every 7 years. Some things are as old as you are. The atoms in your skeleton get replaced every 7 tears, but these aren't the most permanent things in your body.
Regrettably, I can't find a good citation on that, although it's widely cited as the origin for the superstition that breaking a mirror causes seven years of bad luck.
Back in the 1500's and up, when mirrors were smoothed silver on glass, they were only for royalty. And as per royalty, there were servants. The "bad luck" was actually punishment of 7 years of indentured servitude to pay for a broken mirror.
Oh what the things you learn by being in the SCA.