No matter how well we care for our hair, going gray is an inevitable part of getting older. And whether we choose to rock our salt-and-pepper locks or dye them, here’s an interesting fact: Our bodies may actually be telling us something when our hair starts to turn gray. Research shows that a serious illness can cause our hair to turn gray, or hasten the process, and it’s all due to an immune system response.
How Your Immune System Works
If you pick up a viral or bacterial infection, the innate immune system — the defense system with which you were born — is the first part of your immune system to kick into gear. During this stage, the pathogen (virus or bacteria) infects cells in your body. These cells respond by producing interferons, or proteins that can help fight off the infection. Interferons have many duties in the immune system, but they primarily alert the rest of the immune system that there is an invader in the body. (In fact, interferons are so useful that researchers are studying them as a form of therapy for diseases, tumors, and disorders caused by viral infections.)
The Link Between Your Immune System and Gray Hair
So, what does any of this have to do with gray hair? Researchers at the National Institutes of Health and the University of Alabama, Birmingham were just as surprised as any of us to find the connection. In a 2018 study published in PLOS One, the team set out to study stem cells and how our bodies maintain those cells. Stem cells are unique cells that can develop into many different cell types, from brain cells to muscle cells. Most cells in the body are fixed — a heart cell can’t transform into a liver cell, for instance — so stem cells are precious.
Specifically, the team was studying melanocyte stem cells. Melanocyte stem cells are stem cells in our hair follicles. (To remember what the word melanocyte means, think of the word melanin, which refers to the dark brown or black pigment that gives our skin, hair, and eyes color.) Melanocyte stem cells help generate a variety of melanocyte cells inside the hair follicle, and melanocyte cells are what give our hair pigment, or color. A lack of melanocyte cells leads to a lack of pigment, resulting in gray hair.
The researchers found that melanocyte cells function well when interferons inside the cell are regulated and controlled. (Remember: Cells produce interferons when they’re trying to fight off an infection.) But if the melanocyte cells lose control over the interferons — meaning the interferons start multiplying and signaling messages to the rest of the immune system in response to an infection — melanocyte cells and melanocyte stem cells start to die, which can make hair turn gray. If melanocyte stem cells die, those changes could be permanent.
Interpreting the Results
What does this mean? “This new discovery suggests that genes that control pigment in hair and skin also work to control the innate immune system,” William Pavan, study co-author and chief of the Genetic Disease Research Branch at NIH’s National Human Genome Research Institute (NHGRI), explained in a press release. It also suggests that in times of severe illness, the body considers the immune system response to be far more important than producing hair color.
Are you worried about turning gray in response to an illness or infection? Ongoing research suggests that gray hair caused by stress or illness can be reversed. However, this doesn’t mean that your original color will come back. It might be time to embrace the change. After all, gray hair might mean that your immune system is strong — so flaunt those grays with pride!