According to legend, Marie Antoinette’s hair greyed overnight soon before her execution in 1791.
Though the tale is false (hair that has already grown out of the follicle does not change color), a new study from Columbia University’s Vagelos College of Physicians and Surgeons is the first to provide quantifiable evidence associating psychological stress to greying hair in humans.
Grey Hair Due To Stress Might Be Reversible
While it may seem intuitive that stress might hasten greying, the researchers were astonished to learn that hair color can be restored when stress is removed, a result that contradicts a previous study in mice that showed that stressed-induced grey hairs are permanent.
According to the study’s senior author, Martin Picard, Ph.D., associate professor of behavioral medicine (in psychiatry and neurology) at Columbia University Vagelos College of Physicians and Surgeons, the study’s significance extends beyond confirming age-old speculation about the effects of stress on hair color.
Picard believes that understanding the processes that allow elderly grey hairs to revert to their young pigmented states might provide fresh insights into the malleability of human aging in general and how it is impacted by stress.
The findings contribute to a growing body of research indicating that human aging is not a linear, permanent biological process that may be slowed or even reversed in part.
Though people have long thought that psychological stress might cause grey hair to grow faster, scientists have questioned the link due to a lack of sensitive technologies that can accurately correlate periods of stress with hair color at a single-follicle level.
The researchers examined individual hairs from 14 participants. The results were compared to each volunteer’s stress diary, in which they were asked to check their calendars and assess their stress level for each week.
The investigators immediately noticed that some grey hairs naturally regain their original color, which had never been quantitatively documented, Picard says.
When Shannon Rausser, the paper’s second author and a student in Picard’s laboratory, matched hairs with stress diaries, remarkable correlations between stress and hair greying were found, as well as, in some cases, a turnaround of greying with the disperse of stress.
The researchers also analyzed the amounts of hundreds of proteins in the hairs and how protein levels varied along the length of each hair to better understand how stress produces grey hair.
When hair color changed, changes in 300 proteins occurred, and the researchers built a mathematical model that shows stress-induced alterations in mitochondria may explain how stress turns hair grey.
They frequently hear that mitochondria are the powerhouses of the cell, but Picard explains that’s not the only role they play. Mitochondria are tiny antennae inside the cell that respond to a variety of signals, including psychological stress.
The mitochondrial link between stress and hair color varies from what was observed in previous mouse research, which indicated that stress-induced greying was caused by an irreversible loss of stem cells in the hair follicle.
According to co-author Ralf Paus, Ph.D., professor of dermatology at the University of Miami Miller School of Medicine, the results demonstrate that greying is reversible in humans, implying a distinct process. Mice and humans have extremely different hair follicle biology, therefore findings in mice may not transfer well to humans.
Reducing stress in one’s life is a desirable objective, but it won’t necessarily result in normal hair color.
According to Picard, based on their mathematical models, they believe hair must reach a certain point before becoming grey. In middle age, when the hair is close to that barrier due to biological age and other causes, stress pushes it over the threshold and it greys.
However, they don’t believe that lowering stress in a 70-year-old who’s been grey for years will darken their hair, or that raising stress in a 10-year-old will push their hair over the grey barrier.