On the Secret it's been told that your Body Cell regenerate and even rebuild every organs and whatsoever. That means we have a brand new "Young" body in within a year. How comes we are still getting old, since age has "no matter" for the cells.

Yes, it's true that every cell in your body has been replaced over the period of about 7 years (as long as 10 for some cells in the bones).
The reason why we age is toxins accumulate in our bodies causing imperfections in the cells, so they start to duplicate imperfect copies, which is why 'dis-eases' can continue through that period of time.
The movie 'What The Bleep Do We Know' talks about it, and is great all around anyway.

Personally, this is a big part of the reason you may have heard me say again and again that there is no such thing as an incurable disease or injury; your body really is going to rebuild itself anyway, so it's possible to have it build a new and healthy you.
I did a whole healing program about that very thing:
http://www.peacelovemoney.com/5_Success_Library_B4WT.html

Ask me anything