SASKATOON -- Not a fan of your salt and pepper look? Well, there might just be a fix which doesn鈥檛 involve turning to dark shoe polish.
A new small-scale study not only shows strong evidence that psychological stress is linked to the graying of hair but that the process is potentially reversible.
The team from Columbia University Irving Medical Center in New York City, who published their findings in the journal eLife last week, were surprised to discover that hair colour can be restored when stressors are removed.
鈥淯nderstanding 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," the study's senior author Martin Picard told .
"Our data adds 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,鈥� Picard, associate professor of behavioral medicine at Columbia University Vagelos College of Physicians and Surgeons, added.
But authors warned that re-pigmentation of hair was only possible for some.
Most people start noticing their first gray hairs in their 30s or late 20s and the team said this period is when the process is the most reversible. Those who are older who might already have a full head of grey hair are likely be out of luck no matter how much psychological stress they reduce in their lives.
But authors say there鈥檚 some possibility that some hair follicles could be altered by reduced stress.
NEW PROCESS HAS HELPED SHED LIGHT
Contrary to popular belief, hair does not turn grey after it鈥檚 grown out of the follicle -- small, pocket-like holes in our skin on the top of one鈥檚 head. Instead authors explained that when hairs are under the skin, they鈥檙e subject to the influence of internal chemical processes and stress hormones.
And although it鈥檚 been long believed that psychological stress speeds up greying, it鈥檚 been difficult for scientists in general to correlate times of stress with changes to hair pigmentation at a single-follicle level.
But researchers from this latest study say they鈥檙e the first to offer quantitative evidence of the link. And the biggest reason is because of Ayelet Rosenberg, the first author on the study and student in Picard鈥檚 lab.
She developed a new method of capturing highly detailed images of tiny slices of human hairs. Each slice, which is about 1/20th of a millimetre wide, represents about an hour of hair growth, so this precision has greatly bolstered their ability to pinpoint subtle, nearly-imperceptible changes in hair pigmentation.
The team analyzed individual hairs from 14 volunteers and compared the results with entries in stress diaries participants kept for the experiments. Volunteers were asked to catalogue and rate their levels of stress each week.
It鈥檚 through these journals that researchers were able to directly compare hair samples with documented examples of stress in their lives. In the case of one individual for example, Picard said they went on vacation, 鈥渁nd five hairs on that person's head reverted back to dark during the vacation, synchronized in time.鈥�
But one of the issues with the study, which has also been flagged by some experts in , is the need for more data as the sample size was relatively small.
Researchers also looked at the expression levels of thousands of proteins in the hairs and how those values changed as the hair grew out. They discovered when hair colour changed one direction or the other, there was an observable change in about 300 proteins.
The team said their mathematical model suggests stress-induced changes in mitochondria, which act like tiny antennas inside the cell that respond to different signals including stress, helps to explain why grey hairs change.
