Humans have been searching for a cure for aging for as long as they have been capable of pondering their own mortality. In recent times, some scientists have even hinted that aging might not be a biological inevitability, that if we could identify the causes of aging, we might be able to stop it from happening or reverse it entirely.
But there's now some bad news for those of us who have been hoping that science will someday save us from getting old. Researchers at the University of Arizona claim to have developed a mathematical proof that shows how it is intractably impossible to halt the aging process, reports Phys.org.
"Aging is mathematically inevitable - like, seriously inevitable. There's logically, theoretically, mathematically no way out," claimed Joanna Masel, one of the study's researchers.
The proof looks at the competitive balance that exists between the cells of our bodies as we age. On the one hand, most of our cells naturally slow down, and their function deteriorates, as we age. For example, most of us inevitably experience gray hair because our hair cells stop making pigment. On the other hand, there are pockets of cells in the body that rebel against this process; they crank up their growth rate. The only problem? These are cancer cells.
You can slow it down, but you can't stop it
As researchers point out, cancer occurs in all of us as we get older, even if it doesn't cause any symptoms. And the main thing that prevents our cancer cells from consuming us is the existence of our normal, sluggish, aging cells. We need a balance between these forces to stay alive, and such a balance is simply impossible to maintain forever.
Lead author on the study, Paul Nelson, explains the logic of this process: "As you age, most of your cells are ratcheting down and losing function, and they stop growing, as well. But some of your cells are growing like crazy. What we show is that this forms a double bind — a catch-22. If you get rid of those poorly functioning, sluggish cells, then that allows cancer cells to proliferate, and if you get rid of, or slow down, those cancer cells, then that allows sluggish cells to accumulate. So you're stuck between allowing these sluggish cells to accumulate or allowing cancer cells to proliferate, and if you do one you can't do the other. You can't do them both at the same time."
Nelson and Masel seem to have shown that aging is a simple biological inevitability that comes from being multicellular, from having a competing network of cells. Evolution has not solved the problem of aging yet because it never can.
"You might be able to slow down aging but you can't stop it," explained Masel. "We have a mathematical demonstration of why it's impossible to fix both problems. You can fix one problem but you're stuck with the other one. Things will get worse over time, in one of these two ways or both: Either all of your cells will continue to get more sluggish, or you'll get cancer. And the basic reason is that things break. It doesn't matter how much you try and stop them from breaking, you can't."
"It's just something you have to deal with if you want to be a multicellular organism," Nelson added.
The research is published in the Proceedings of the National Academy of Sciences.