Legend has it that Marie Antoinette’s hair turned gray during the night just before she was beheaded in 1791.
Although the legend is inaccurate …hair which has already grown from the follicle does not change color; a new study by researchers at Columbia University’s College of Physicians and Surgeons is the first to offer quantitative evidence linking psychological stress to gray hair.
And while it may seem intuitive that stress can speed up gray, researchers were surprised to find out hair color it can be restored when stress is removed, a finding that contrasts with a recent study in mice that suggested that stress-induced gray hairs are permanent.
The study, published on June 22 a eLife, has a broader significance than confirming centuries – old speculations about the effects of stress about hair color, says study author Martin Picard, Ph.D., associate professor of behavioral medicine (in psychiatry and neurology) at Columbia College of Physicians and Surgeons at Vagelos University.
“Understanding the mechanisms that allow old gray hairs to return to their‘ young ’pigmented states could give new clues about the malleability of human aging in general and how it is influenced by stress,” says Picard.
“Our data add to a growing body of evidence that shows that human aging is not a linear and fixed biological process, but that it can at least in part be stopped or even temporarily reversed.”
Study hair as a way to investigate aging
“Just as the rings of a tree trunk contain information about decades spent in the life of a tree, our hair contains information about our biological history,” Picard says. “When hairs are still under the skin like follicles, they are subjected to the influence of stress hormones and other things that happen to our mind and body. Once the hairs grow from the leather hair, these exposures are permanently hardened and crystallized in a stable way. “
Although people have long believed that psychological stress can speed up gray hair, scientists have debated the connection due to the lack of sensitive methods that can accurately correlate stressful moments with hair pigmentation. at a single follicle level.
Dividing hair to document hair pigmentation, Ayelet Rosenberg, the study’s lead author and student at Picard’s lab, developed a new method for capturing highly detailed images of small slices of human hair to quantify the extent of loss. of pigment (thickening) in each of these slices. Each slice, about twenty millimeters wide, represents about an hour of hair growth.
“If you use your eyes to look at a hair, it will look like it has the same color, unless there is a major transition,” Picard says. “Under a high-resolution scanner, you see small, subtle color variations, and that’s what we measure.”
The researchers analyzed individual hairs from 14 volunteers. The results were compared with each volunteer’s stress diary, in which people were asked to review their calendars and assess each week’s stress level.
The researchers immediately noticed that some gray hairs naturally regained their original color, which had never been documented quantitatively, Picard says.
When Shannon Rausser, second author of the paper and a student at Picard’s lab, aligned her hair with stress diaries, striking associations between stress and gray hair and, in some cases, the inversion of gray were revealed. with the lifting of stress.
“There was one person who went on vacation and five hairs on that person’s head went back into the dark during the holidays, synchronized in time,” Picard says.
Blame the mind-mitochondrion connection
To better understand how stress causes gray hair, the researchers also measured the levels of thousands of proteins in the hair and how they changed the protein levels throughout each hair.
Changes in 300 proteins occurred when hair color changed and researchers developed a mathematical model this suggests that stress-induced changes in mitochondria may explain how stress becomes grayish.
“We often feel that mitochondria are the engine of the cell, but that’s not the only role they play,” Picard says. “Mitochondria are actually like small antennae inside the cell that respond to a number of different signals, including psychological stress. “
The connection of mitochondria between stress and hair color differs from the discovery in a recent study in mice, which found that stress-induced grayness was caused by an irreversible loss of stem cells in the follicle. hairy.
“Our data show that greyness is reversible in people, which implies a different mechanism,” says co-author Ralf Paus, PhD, a professor of dermatology at Miller University School of Medicine. “Mice have a very different hair follicle biology and may be a case where findings in mice do not translate well to people.”
Hair pigmentation is only possible for some
Reducing stress in life is a good goal, but it will not necessarily turn hair into a normal color.
“Based on mathematical modeling, we believe that hair has to reach a threshold before it turns gray,” says Picard. “In middle age, when hair is close to this threshold due to biological age and other factors, stress will make it pass above the threshold and turn gray.
“But we don’t think reducing stress in a 70-year-old man who has been gray for years will darken or increase Stress in a ten-year-old boy it will be enough to tilt his hair over the gray threshold. ”
Ayelet M. Rosenberg et al, Quantitative mapping of gray color and inversion of human hair in relation to life stress, eLife (2021). DOI: 10.7554 / eLife.67437
Columbia University Irving Medical Center
Citation: True: stress turns gray (and is reversible) (2021, June 22) recovered on June 22, 2021 at https://medicalxpress.com/news/2021-06-true-stress-hair- gray-reversible.html
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