Gray hair can appear due to stress
And it's reversible
Tatiana Matveeva, "Scientific Russia"
Scientists from Columbia University (USA) have proved that psychological stress is associated with the formation of gray hair in people. At the same time, the hair color can be restored as soon as the stress level decreases. This is a discovery that contrasts with a recent study on mice, which showed that stress-induced gray hair remains that way, the press service of the Columbia University Medical Center reports. The results of the new work are published in the journal eLife (Rosenberg et al., Quantitative mapping of human hair greying and reversal in relation to life stress).
Just as the rings in the trunk contain information about the last decades of the tree's life, our hair contains information about our biological history, the authors note. When the hair is still under the skin in the form of follicles, they are affected by stress hormones and other processes occurring in our mind and body. When the hair grows out of the scalp, they crystallize these effects.
Although for a long time it was believed that psychological stress could accelerate the growth of gray hair, such a conclusion could appear because there were no sensitive methods that could accurately compare the time of stress with hair pigmentation at the level of one follicle.
In this study, scientists from Columbia University have developed a new method for obtaining highly detailed images of tiny sections of human hair in order to quantify the degree of pigment loss (graying) on each section of the hair. Each slice with a width of about 1/20 millimeters corresponds to about an hour of hair growth. Under a high-resolution scanner, scientists see small subtle color variations along the length of the entire hair that the human eye cannot distinguish.
The researchers analyzed individual hairs of 14 volunteers. The results were compared with each person's stress diary: study participants assessed their stress levels each week. Scientists immediately noticed that some gray hair naturally restores its original color. For example, one person's five gray hairs turned dark again during his vacation, synchronized in time.
To better understand how stress causes gray hair, the researchers also measured the levels of thousands of proteins in the hair and their variation along the length of each hair. When the hair color changed, there were changes in 300 proteins, and the researchers developed a mathematical model that suggests that stress-induced changes in mitochondria can explain how stress leads to gray hair.
The authors of the work note that repeated pigmentation of hair is not possible in all people. "Based on our mathematical modeling, we believe that hair should reach the threshold before it turns gray," the press release notes. – In middle age, when the hair is close to this threshold due to biological age and other factors, stress will push them to the threshold value, and they will turn gray." They emphasize that reducing stress in a 70-year-old man who turned gray many years ago will not return his hair to its former color. And more stress in a 10-year-old child is unlikely to interrupt the "gray threshold" of his hair.
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