A new study from Massachusetts General Hospital (MGH) discovered that redheads could handle pain better than others. This may sound strange, but researchers believe they’ve found why this occurs. In humans and mice with red hair, their skin’s pigment-producing cells lack a specific receptor’s functioning. Without this receptor, changes happen, which cause an imbalance in pain sensitivity and tolerance.
What does hair color have to do with pain?
Researchers believe these findings may help in developing future treatments for pain management. This groundbreaking study finally uncovers why redheads seem to deal with pain better than people with other hair colors. These findings have been published in the magazine Science Advances.
The skin of people who have red hair and other species with red fur have pigment-producing cells called melanocytes. This cell contains a variant form of the melanocortin 1 receptor. The cell surface houses this receptor, and if circulating hormones called melanocortins activate it, pigment changes occur. It triggers the melanocyte to produce brown or black melanin pigment instead of yellow or red.
Previous work by David E. Fisher, MD, Ph.D., uncovered an interesting fact about melanin pigment in redheads. The study found that redheads have trouble getting a tan due to inactive variants of the melanocortin 1 receptor. Fisher is the director of the Mass General Cancer Center’s Melanoma Program and director of MGH’s Cutaneous Biology Research Center.
For this study, Fisher and his colleagues wanted to investigate why redheads have a higher pain tolerance. To do this, they studied a strain of red-haired mice that, along with humans, have inactive melanocortin 1 receptors. These mice also had higher pain tolerances than mice with other hair colors.
Why non-functioning melanocortin 1 receptors increase pain tolerance in redheads
The team discovered why the inactive variant of this receptor resulted in a better capability of managing pain. In the red-haired mice, deactivation of this receptor caused lower levels of POMC (proopiomelanocortin) molecules to be secreted from their melanocytes. This molecule contains various hormones, including one that increases pain sensitivity and one that inhibits pain. These hormones strike a balance between opioid receptors that block pain and melanocortin four receptors, increasing pain sensitivity.
You might conclude that having low levels of both hormones would cancel each other out in red-haired mice and humans. However, the body produces other hormones and chemicals not related to the melanocyte, which activate opioid receptors. Having lower levels of melanocyte-related hormones leads to an increase in opioid signals, which help block pain. Therefore, pain tolerance in redheads goes up as well.
Fisher says this:
“These findings describe the mechanistic basis behind earlier evidence suggesting varied pain thresholds in different pigmentation backgrounds. Understanding this mechanism provides validation of this earlier evidence and a valuable recognition for medical personnel when caring for patients whose pain sensitivities may vary.”
Fisher says that the findings may revolutionize treatments for controlling and managing pain by working with the body’s natural processes. For instance, perhaps new medications will become available that block melanocortin four receptors that send pain signals to the brain. Then, people with other hair colors would benefit from what redheads get to enjoy naturally.
“Our ongoing work is focused on elucidating how additional skin-derived signals regulate pain and opioid signaling,” adds co-lead author Lajos V. Kemény, MD, Ph.D., a research fellow in Dermatology at MGH. “Understanding these pathways in depth may lead to the identification of novel pain-modulating strategies.”
The National Institutes of Health, the Melanoma Research Alliance, and the U.S.-Israel Binational Science Foundation helped fund this research. Dr. Miriam and Sheldon G. Adelson Medical Research Foundation supported the study as well.
In addition to having a higher pain tolerance, redheads have other unique quirks about them. All hair colors are beautiful, but people with red hair benefit more in specific ways.
Other interesting facts about redheads
- A genetic mutation is responsible for red hair. Both parents must carry the modified MC1R, or melanocortin 1 receptor, to produce red-headed children. Interestingly, parents with this gene mutation who don’t have red hair have a 25% chance of having redheads.
- Red hair occurs in less than 2% of people worldwide. Having red hair is extremely rare; in fact, only about 140 million people have it. Scotland has the highest percentage of redheads (13%), and Ireland comes in second at 10% of the population.
- Red hair occurs most frequently in those of European descent. If you have northern or western European ancestry, you have a greater chance of being a redhead. 2-6% of people with this background have red hair; it occurs much less often in people of other ethnicities.
- Dyeing red hair is challenging for those who want an auburn hue. Red hair is more challenging to dye than any other color. This is because it holds pigment tighter than different hair colors. So, before you even bleach your hair, the color must be stripped, which can cause damage.
- Redheads have less hair. On average, redheads have 90,000 strands of hair, while blondes have 110,000. Brunettes have the most, at 140,000. To make up for having less hair, however, redheads tend to have more voluminous hair.
- Blue-eyed redheads are the rarest people on Earth. Most people with red hair have brown eyes; hazel or green eyes are the second most common. Those who have blue eyes are highly uncommon.
- People with red hair have a higher risk of skin cancer. Because they have less melanin, they’re more susceptible to developing skin cancer. According to the International Journal of Cancer, their risk is 2.5 times higher than people with other hair colors.
Final Thoughts: The study reveals why redheads have a higher pain tolerance than others
Redheads don’t have a functional melanocortin 1 receptor, which helps detect pain. Activation of this protein creates brown or black melanin pigment; lack of it causes red or yellow. Lack of this receptor, along with a rise in opioid signals, increases their tolerance to pain. Researchers believe that this finding will improve treatments for pain management in the future by targeting this receptor.