A study provides new scientific evidence supporting a link between stress and gray hair. The researchers also identified proteins that appear to drive this process. And according to them, it could even be reversed.
Legend has it that Marie-Antoinette, the last queen of France, saw her hair turn completely white on the night before she ascended the scaffold, on October 16, 1793. This “sudden graying” syndromeas it is called, which is characterized by very rapid whitening of the hair, is also said to have been noted by combatants in the Second World War. This particular phenomenon has not been observed scientifically. On the other hand, growing evidence suggests that stress can actually speed up the process of whitening our hair.
Why does our hair turn white?
The pigmentation of our hair comes from melanin (a term grouping together dark colored biological pigments). These pigments are produced by melanocyte granules in the bulb of the hair follicle, in contact with keratinocytes, which produce hair by multiplying. With time, the number of melanocytes gradually decreases. In other words, there are less and less pigments available, so much so that after a while, our hair turns gray, and finally white.
However, time is not the only factor responsible for the loss of our melanocytes. As part of a study published in January in Nature, a team of researchers noticed that in cases of deep stress, norepinephrine, a neurotransmitter of the sympathetic nervous system which plays a leading role in the stress response. , could be taken up by melanocyte stem cells. Consequently, the melanocytes become activated and the pigment reservoir tends to become exhausted very quickly.
However, this work had been carried out in mice. And what happens in mice does not necessarily translate into humans.
A clearly established link
In another study published a few days ago in the journal eLife, researchers at Columbia University also examined the link between psychological stress and graying hair, this time in humans.
For this work, the scientists recruited fourteen volunteers who were asked to keep “stress diaries”. These people then provided hair samples, which the scientists divided into slices one-twentieth of a millimeter wide. Each slice represented approximately one hour of hair growth. By analyzing them with a high-resolution scanner, the researchers have given themselves the means to map the degree of graying (invisible to the naked eye) on a time scale.
At the end of these analyses, the researchers effectively highlighted “ striking associations » between stressful events reported in the newspapers and graying of hair.
A process… reversible
More surprisingly, they also reported a reversal of this graying process as stress was alleviated. Five hairs on the head of a person going on vacation would thus be “rturned black during his leave, synchronized in time“, reports Ayelet Rosenberg, main author of the study. Such a phenomenon had never been quantitatively documented, according to the researchers.
During this work, the scientists also measured the levels of thousands of different proteins along the length of the hair. They then identified changes in three hundred of them as their hair turned gray. Using a mathematical model, the team then linked these alterations to the changes induced by stress in mitochondria.
While reducing stress could actually reverse the hair loss process, don’t count on it to get your hair back to its former color. Time is a much more formidable factor. On the other hand, subtle changes could occur in middle-aged people.
« Based on our mathematical modeling, we believe that hair must reach a certain threshold before turning gray“, notes the researcher. “ In middle age, when hair is close to this threshold due to biological age and other factors, stress will push it past the threshold and it will turn gray“. If stress is reduced, it could therefore be possible to bring them below this threshold… for a while!
These findings open up fascinating new perspectives for research into aging and stress management. They suggest that the connection between body and mind is even closer than previously thought, offering an avenue for future treatments aimed at slowing or even reversing some of the effects of aging. If hair graying can be influenced by stress, what about other age-related biological processes? This question remains unanswered, but it could well transform our understanding of aging and how to cope with it.
