A new study conducted at Columbia University offers quantitative evidence that psychological stress leads to graying hair in people, per a press statement. Crucially, the findings show that these effects are reversible in some people, providing insight into the wider aging process in humans.
The research adds to a growing field of evidence suggesting that aging is not a linear process, and in the long run, it could help to engineer new methods for slowing or even reversing aging in humans.
What does the study say?
It might seem obvious that stress can lead to gray hairs, as it is something that has been widely accepted by the public for years.
Still, the new paper, published in eLife, puts any doubt about the link between graying hair and stress to rest, and it also reveals the surprising discovery that hair color can be restored when stress is reduced. The new findings contrast with another recent study that suggests gray hairs from stress are permanent, based on studies on mice.
For their study, the researchers analyzed the hair of 14 volunteers under a high-resolution scanner that could show even the subtlest variations in color. They compared their findings with each volunteer's daily stress levels, which were recorded in a journal.
The researchers found that some gray hairs naturally regained their original color, which had never been quantitatively recorded, the study's senior author Martin Picard, Ph.D., explained.
The researchers ultimately found that there was a striking correlation between the volunteers' stress levels and the graying of their hair follicles. In some cases, they observed a reversal of graying correlated with a reduction of stress in the life of a volunteer.
"There was one individual who went on vacation, and five hairs on that person’s head reverted back to dark during the vacation, synchronized in time," Picard explained.
The researchers also studied the levels of thousands of proteins in the human body and developed a mathematical model that points to stress-induced changes in the protein mitochondria leading to gray hairs.
'New clues about the malleability of human aging'
The study also serves a greater purpose than simply confirming the effects of stress on the color of our hair.
"Understanding the mechanisms that allow 'old' gray hairs to return to their 'young' pigmented states could yield new clues about the malleability of human aging in general and how it is influenced by stress," said Martin Picard.
"Our data add to a growing body of evidence demonstrating that human aging is not a linear, fixed biological process but may, at least in part, be halted or even temporarily reversed," Picard continued.
The senior author of the study explained that our hair contains information about our biological history, much in the same way as the rings in tree trunks reveal information about the age of a tree.
When still under the skin of our scalps, hair is exposed to stress hormones and other effects within the body. Once they grow out of our heads, they harden and can be analyzed to provide data about the processes occurring under the human's skin.
Other aging reversal studies
The Columbia University study isn't the first to give early indications that aging might, at least temporarily, be reversible. In April, a study published in Nature, showed that DNA damage plays a central role in the aging process.
In May 2020, meanwhile, scientists injected aged rats with young rat plasma and showed that the method reversed epigenetic changes in the animals, resulting in improved organ functions. The researchers stated that their method reverse-aged the rats by 54 percent.
All of this is far from giving any guarantees that age halting or reversal methods will ever come close to being successful. In fact, a study from an international group of researchers recently countered the most recent findings by suggesting that aging is not reversible.
Still, the latest research is already inspiring a new generation of scientists to strive towards the possibly futile goal of making humans immortal. Watch this space.