Growing old is a natural part of life, but that hasn’t stopped people from turning to anti-aging skin treatments, specialized diets and other tricks to try to reverse the effects of aging.
A new study suggests, however, that these efforts to stop aging may be sorely misplaced: No matter how people try to intervene, it’s mathematically impossible to stop the aging process.
“Aging is mathematically inevitable — like, seriously inevitable,” senior study author Joanna Masel, a professor of ecology and evolutionary biology at the University of Arizona, said in a statement. “There’s logically, theoretically, mathematically no way out.” [Extending Life: 7 Ways to Live Past 100]
The researchers’ conclusion is based on how individual cells in the body function and work together. As a person ages, one of two things happens to individual cells: A cell will either slow down and lose function (such as when a person’s hair cells stop producing pigment and turn gray) or a cell can proliferate uncontrollably, or in other words, become cancerous, according to the study, published Monday (Oct. 30) in the journal Proceedings of the National Academy of Sciences. (As people age, they tend to develop cancer cells in the body, even if these cells don’t cause symptoms, the researchers said.)
In the study, researchers created mathematical models of intercellular competition. The idea of natural selection, or “survival of the fittest,” suggests that weeding out the “sluggish” cells could stop the aging process. However, cutting out these cells leaves room for cancer cells to proliferate. On the other hand, if you get rid of the cancer cells, sluggish cells linked to aging will accumulate and slowly deteriorate, the study found.
“As you age, most of your cells are ratcheting down and losing function, and they stop growing as well,” lead study author Paul Nelson, a postdoctoral researcher at the University of Arizona, said in the statement. “But some of your cells are growing like crazy. What we show is that this forms a double bind — a catch-22.”
And even if selection were perfect — say, for example, if the body got rid of sluggish cells and kept cancer cells in check — multicellular organisms would still age, because cancer cells seem to “cheat” when cells are forced to compete for resource and ultimately outcompete other cells, the researchers said in the study.
“You might be able to slow down aging but you can’t stop it,” Masel said. “You can fix one problem, but you’re stuck with the other one.”
And over time, things will get worse in either one or both of the ways the researchers highlighted. “Either all of your cells will continue to get more sluggish, or you’ll get cancer,” Masel said.
The basic reason for this, Masel added, “is that things break. It doesn’t matter how much you try and stop them from breaking — you can’t.”
Ultimately, aging is “just something you have to deal with if you want to be a multicellular organism,” Nelson said.